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Building Tips and technical articles. => Paint and finishing => Topic started by: Larry Renger on July 18, 2013, 11:10:57 PM

Title: SLC OVER Polyspan?
Post by: Larry Renger on July 18, 2013, 11:10:57 PM
It seems as though one can apply SLC covering over undoped Polyspan, and get a slick, incredibly light base for painting.  I'm going to try it on a plane I am rebuilding. News as it happens.
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on July 19, 2013, 08:21:51 AM
In my experience that is backwards.   It is SLC first then the Poly-Span to get the silkspan look so many like.  Also doing the SLC first you have to remember to get the scouring pad out and buff it a little.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on July 19, 2013, 09:23:59 AM
Yes, Doc, I know it is backwards. But I don't want a silkspan look finish, I want a super light high gloss paint finish.

By using the SLC instead of dope, it should bond everywhere to the Polyspan and make an extra strong and slick covering job.

My actual question was whether it has been tried!
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on July 21, 2013, 07:11:35 PM
OK, I am trying this type of finish!

See my Baby Clown thread in the 1/2A section for progress.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on July 22, 2013, 04:00:02 PM
It works fantastic!  The weight, by an actual test sample, is 1.46 oz/sq.yard.  The structural rigidity it adds is amazing.  I have some technique to work on as far as flawless tips, but the ones I did aren't horrible.

Now I need to work on how to properly paint it.  I have a sample piece drying. It is Painters' Choice right on the steel wool buffed SLC.
Title: Re: SLC OVER Polyspan?
Post by: Motorman on July 23, 2013, 06:16:41 AM
Could you just paint the polyspan then gloss it with the SLC? If SLC doesn't add strength why would you put it under polyspan then have to paint the polyspan anyway?


MM
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on July 23, 2013, 07:12:25 AM
The point is to not have to fill the Polyspan weave with heavy coats of dope and filler. The SLC does all that, and by bonding to the Polyspan adds tremendous rigidity to the wing structure. The only dope used is enough to bond the Polyspan to the wing structure. No dope on the open bays at all!

I expect that the SLC underneath with Polyspan doped over it gets the same strength gain, and is reputed to save weight compared to filling the weave with dope alone. But SLC on top does it all, lighter.

If one used dyed covering such as silkspan, your finish would be done in one shot. Also, use of some of the ultralight films intended for parkflyers becomes practical for big models. More experimentationto be done!

See the Baby Clown thread in the 1/2A section for a photo of the wing.
Title: Re: SLC OVER Polyspan?
Post by: Lauri Malila on July 23, 2013, 10:38:16 AM
Hi.

It depends on what is your idea of a slick surface. The plastic film will propably mirror all imperfections from the base surface, it means that the paper has to be filled well anyway. Personally I would do it in the opposite way.
But for quick & dirty finish, why not!

Lauri

Ps. People should test the polyester fabric (ripstop) materials, like Icarex, in cl models too. They are extremely strong, stabile and easy to use. They have allready made the Polyspan allmost history in Many free flight categories.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on July 23, 2013, 10:52:25 AM
The imperfections can be filled with primer on the SLC after a quick wet sanding to kill the gloss. There is no reason to fill the paper!
Title: Re: SLC OVER Polyspan?
Post by: Lauri Malila on July 23, 2013, 11:01:24 AM
Sorry, didn't notice that you are going to paint it, too. In that case, why not. Or just forget the Polyspan and cover with slightly thicker Mylar (I guess that's what SLC is, too). It can be painted, that's the standard practise in eastern Europe. L
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on July 23, 2013, 04:24:11 PM
With out doing actual destructive impact tests, I believe the composite of fiber and film is way tougher and more rigid than either alone.
Title: Re: SLC OVER Polyspan?
Post by: Andrew Tinsley on July 26, 2013, 03:39:40 PM
Hello Larry,
I don't have a clue what SLC is, but it sounds as though your system is similar to mine. I cover the airfame with very thin mylar that the FF boys use. Stick it on with balsaloc or thinned down impct adhesive. then cover with dyed silk and one coat of 50/50% thinned dope. Fuel proof to taste. It is incredibly strong and lighter than silk onits own as you don't need to seal the silk.

Andrew.
Title: Re: SLC OVER Polyspan
Post by: Larry Renger on July 26, 2013, 11:15:34 PM
Nope, sorry, you have completely missed the point! The Polyspan, silk, japanese tissue, or silkspan is attached only around the periphery, then the SLC (super light covering, a vey thin Mylar with adhesive coating) is applied OVER it and heat bonded to the fiber underlayer. The fiber layer, whatever it is, is NOT DOPED IN THE OPEN BAYS. The SLC provides both the function of filler, binding film and fuel proofing even if no other finish is applied.

The result is a composite covering that is incredibly light, tough and rigid, but fuel proof or paint ready without multiple layers of dope and filler.

This way of covering is exactly reversed from your standard practice of covering with SLC then applying one of the fiber coverings doped over it. Yes that works, but you still have to then apply dope to fill the fiber and fuelproof it. Putting the SLC on top of the raw fiber gives you the same strength with a LOT less work, time and weight. Also, IMHO a better finish than I have the patience to achieve otherwise.

As mentioned elsewhere, with Polyspan, the result weighs. only 1.4 ounces per sq.yard.
Title: Re: SLC OVER Polyspan?
Post by: Bill Little on July 27, 2013, 01:31:35 PM
With out doing actual destructive impact tests, I believe the composite of fiber and film is way tougher and more rigid than either alone.

Hi Larry,

I agree 100% on your supposition that the two, together, are stronger than either alone.

BIG Bear
RNMM/AMM
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on July 28, 2013, 09:32:58 PM
One day of flying, and so far, no separation.  I will keep everyone posted on how this technique works out on the long term.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on August 03, 2013, 09:47:50 PM
Two weeks later, all is still staying stuck where it is  supposed to.  So far, so good. Give it a try! No dope on the Polyspan, the SLC bonds to it and stabilizes the structure like you wouldn't believe, and then provides a totally smooth surface for painting (after you rough up the outer surface with wet sanded 600 grit) I don't think you even need primer! Maybe for a 20 point finish, a primer coat and blocking coat might be needed, but not for us normal mortals.

Think about it, 1 sq yard will cover just about any model you can imagine, and it only weight 1.5 ounces ready for paint.  What does a dope over tissue or Polyspan surface weigh for that area? or even a Polyspan OVER SLC?  You are totally eliminating the filler coats of dope to achieve a smooth surface, not counting the time and effort required. The bond between the SLC and fiber is really strong. Dope would just get in the way.

My next trick is to try some of the ultra-light park flyer coverings over the Polyspan to get color without paint at all!
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on August 04, 2013, 08:30:01 PM
Anyone else tried this yet?  H^^
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on August 05, 2013, 09:04:49 AM
My next plane.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on August 14, 2013, 10:44:37 PM
So, what brave soul will be the first to try this? It REALLY works.
Title: Re: SLC OVER Polyspan?
Post by: Will Hinton on August 15, 2013, 07:11:54 PM
I'm curious as to whether we even need the polyspan.  After all, the SLC on my speed limit combat ships took a horrible beating and held up.  Can we just use SLC for our covering and save the labor/weight?
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on August 16, 2013, 06:57:56 AM
I dunno, try it and you tell us!  

I think that technique is called Monokoating. except for the painting part. VD~

The point to the laminating technique is that the resulting composite covering seems to be incredibly rigid and tough. It should also not allow spreading tears if punctured. Mind you, I'm not going to crash into a tree or something to prove that!

Time will tell whether it is resistant to wrinkling with temperature changes as film-only coverings do.

People have been using SLC/Polyspan composite covering for years, but in my opinion, backwards, resulting in excess work, extra expense and mostly weight penalty. With the SLC over the Polyspan you automatically have a filled, smooth surface ready for final finish. 

Since the film bonds fully to the fibers, the result is way stronger and more stable than either alone.
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on August 16, 2013, 08:28:45 AM
I have several planes with just SLC covering.  A couple I darkened with magic marker before covering the plane.  One I painted the SLC after using scouring pad.   I want to try Larry's method on the next plane.
Title: Re: SLC OVER Polyspan?
Post by: phil c on August 16, 2013, 06:24:06 PM
Thanks for the interesting experiment Larry.  It's a good idea.  I don't like to build wings with wood, cause they really break in a crash.  So I've ended up with a foam wing, filled with lightweight filler(1 oz), covered with SLC (1.5 oz) on a 700 sq.in. wing plus fuse and tail feathers, one coat of primer sanded off(20 gr), one coat of white enamel(2 oz) and some trim coloring(1 oz).   About 6 oz. from the bare structure.
Title: Re: SLC OVER Polyspan?
Post by: Jim Roselle on August 28, 2013, 07:01:22 AM
Does the poly/slc loosen when exposed to heat and intense sunlight like ultracoat and monokote do?

Jim
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on August 28, 2013, 08:59:55 AM
Not so far. It has been hot here, but only been out with it about 4 days.

Update to 6 days with 90 deg temps experienced.
Title: Re: SLC OVER Polyspan?
Post by: Rick Huff on September 25, 2014, 06:45:19 AM
Larry,
Any further reports?  Is there any paint peeling or covering delaminating?
Thanks,
Rick
Title: Re: SLC OVER Polyspan?
Post by: Tom Niebuhr on September 25, 2014, 08:31:04 AM
Lauri,
Icarex is used in kites. Is it heat shrinkable like polyspan?
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on September 28, 2014, 06:47:07 AM
I am not familiar with Icarex, so can't give you an answer.

Larry
Title: Re: SLC OVER Polyspan?
Post by: Lauri Malila on September 28, 2014, 08:26:23 AM
Yes it heat-shrinks. Icarex is OK and many people use it. But now there is a slightly better (lighter) japanese equivalent, made by Daichi Orimono.
Just to make it airtight it does not need dope (unlike Icarex) but I put 2 coats and then wet sand #2000 to make surface better.
You glue it on with thinned contact cement (UHU for soft plastics is best): 3 coats to framework and then iron it on.

L
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on September 28, 2014, 08:35:31 AM
Where can you buy this material?
Title: Re: SLC OVER Polyspan?
Post by: Lauri Malila on September 28, 2014, 08:57:47 AM
You should ask local FF guys..? Not those who do the vintage crap, but real FAI free flight people.
I get mine via friends in Norway or Finland so don't really know about real distributors. L

Ps. I see you live in California. I'll be there in February to fly some FF, in Lost Hills.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on October 28, 2014, 09:10:28 PM
Wow, 1000 + views! And nobody has tried it?  HB~>
Title: Re: SLC OVER Polyspan?
Post by: Akihiro Danjo on October 29, 2014, 12:19:03 AM
Yes it heat-shrinks. Icarex is OK and many people use it. But now there is a slightly better (lighter) japanese equivalent, made by Daichi Orimono.
Just to make it airtight it does not need dope (unlike Icarex) but I put 2 coats and then wet sand #2000 to make surface better.
You glue it on with thinned contact cement (UHU for soft plastics is best): 3 coats to framework and then iron it on.

L

Hi Lauri san,
Isn't it POWER RIP?
Power Rip is produced by Teijin and distributed by Daiichi Orimono.

I have never used the plastic films without heat-adhesive coating.
How do you overlap the films around wing tip? Brush on some glue over the first film before overlapping?
Is it easy to cover the tip? Heat, pull and heat-glue just like other plastic flims?

Aki

PS, I remember that the model of my profile photo is covered with SLC over Silkpan...sorry, not Polyspan
Title: Re: SLC OVER Polyspan?
Post by: Lauri Malila on October 29, 2014, 10:12:36 AM
Hi Aki!

It's very possible. But I am not sure, I will confirm it from my supplier.
I never cover tips or even D-box with it, only open construction. I cover each wing panel (F1A) with one piece, wrapping around t.e. Glue seam in perimeter is 3...5mm wide.
I cover carbon D-box and tips with lightest modellspan paper and then over seams with light Esaki tissue.
Paper-covered D-boxes are slightly lighter, better looking and easier to repair.

Lauri

Title: Re: SLC OVER Polyspan?
Post by: Rick Huff on October 29, 2014, 12:44:09 PM
Larry,

I have covered two planes with your concept of SLC over polyspan.  The first was my brother's RSM Mark 1 trainer.  He didn't want it painted and was very happy with the "look" of the SLC over polyspan.  It's also tough as nails.  The second plane I covered with SLC over polyspan is my new Joe Dill Chipmunk.  I painted the SLC (after scuffing with 2000 grit sandpaper) with auto 2-part acrylic urethane.   It came out beautifully.  Attached is a photo of it (without its canopy).  Of course, I'm hoping that it stays looking that way.  Only time will tell.

Rick
Title: Re: SLC OVER Polyspan?
Post by: Tom Luciano on October 29, 2014, 04:26:57 PM
Looks great Rick!!

Tom
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on October 31, 2014, 08:28:17 AM
Beautiful indeed! Any idea what the weight saving was?  H^^
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on October 31, 2014, 09:42:34 AM
Will try to remember to try this on my next plane.   I didn't think of it or remember when I did the RSM Ringmaster and the Canard Ringmaster.   
Title: Re: SLC OVER Polyspan?
Post by: Rick Huff on October 31, 2014, 01:51:38 PM
Larry,
I don't know for sure, but the entire finish including the weight of the Polyspan and SLC was 7 oz.  I'm pretty sure it would have been heavier with either silkspan or polyspan (by the time I filled the voids).  However, the SLC over Polyspan is so much tougher that I would use it even if there weren't any weight savings.  I guess I'm most concerned about the long term behavior of the SLC over Polyspan.  Will there be any paint delaminations, will there be any wrinkles?  After one month, there are absolutely no problems. 
Thank you for coming up with, and sharing this concept.
Rick
Title: Re: SLC OVER Polyspan?
Post by: Mike Griffin on October 31, 2014, 08:55:52 PM
Larry what heat setting are you using on your iron to iron down the SLC to the Polyspan?

Thank you
Mike
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on November 01, 2014, 03:24:14 PM
I use just enough heat to activate the adhesive until I get to the tips, then enough to allow stretching the film.
Title: Re: SLC OVER Polyspan?
Post by: Mike Griffin on November 01, 2014, 04:23:16 PM
Do you use your heat gun at all.  The reason I am asking is that I am going to try this.

Thanks

Mike
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on November 02, 2014, 06:06:18 AM
I rarelyuse a heat gun as I tend to burn holes. HB~>
Title: Re: SLC OVER Polyspan?
Post by: Akihiro Danjo on November 03, 2014, 11:37:48 AM
Do you use your heat gun at all.  The reason I am asking is that I am going to try this.

Thanks

Mike

Mike san,
Even a 500W hair dryer can burn holes, so you don't have to use a heat gun at all.
I cannot remember why I know about it....

Aki
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on November 21, 2014, 07:14:49 PM
I just checked the date for when I did the first job, and it was early July. So far no problems except abrasions from inverted landings... :-[ Didn't go all the way through, though. That combo is TOUGH!  #^
Title: Re: SLC OVER Polyspan?
Post by: billbyles on November 24, 2014, 04:01:41 PM
Larry,
I don't know for sure, but the entire finish including the weight of the Polyspan and SLC was 7 oz.  I'm pretty sure it would have been heavier with either silkspan or polyspan (by the time I filled the voids).  However, the SLC over Polyspan is so much tougher that I would use it even if there weren't any weight savings.  I guess I'm most concerned about the long term behavior of the SLC over Polyspan.  Will there be any paint delaminations, will there be any wrinkles?  After one month, there are absolutely no problems.  
Thank you for coming up with, and sharing this concept.
Rick

"...but the entire finish including the weight of the Polyspan and SLC was 7 oz."

The weight of the entire cover (silkspan) and dope finish on my Impact (700 in^2) is 8 oz.  Larry has seen the finish; I'd estimate from my last Impact (which had the same cover and finish) that it is an 18 to 19 point finish. My last Impact had over 2,200 flights on it with the same cover & finish and while I will grant that the SLC over Polyspan is a much tougher cover I never did get any holes/tears in the cover including trips to the Nats & many other contests.  The new process might be the way to go if you tend to get holes/tears in your cover, if you are in a situation where you are unable to use a dope finish, or just don't want to do that much work to get the finish.
Title: Re: SLC OVER Polyspan?
Post by: Rick Huff on November 25, 2014, 01:18:13 PM
Bill,
Thanks for the encouragement to a beginner flier.
Rick
Title: Re: SLC OVER Polyspan?
Post by: Avaiojet on November 26, 2014, 01:36:31 PM
Sounds like a great way to cover a model.

What I don't understand is how do you keep the overlap from showing when you paint?

Or do you do both top and bottom together?
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on November 27, 2014, 09:34:27 AM
When you are several feet away the overlap does not show.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on November 29, 2014, 05:21:06 AM
A light dusting of primer will hide the seam when sanding the film for painting. That is the only place you really need to prime if you are worried about it.
Title: Re: SLC OVER Polyspan?
Post by: Doug Burright on February 18, 2015, 11:06:12 PM
Larry,

So, just what the heck IS SLC, and where do we get it?
 I know the process for silkspan and dope, etc., but what is the SLC?
I would be more than happy to put a lighter, stronger finish on the airplane, but have no idea what the SLC is.
Please explain.
Thanks,
Doug.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on February 21, 2015, 11:54:01 AM
SLC is a thin film with adhesive backing. It is applied with an iron ant then heat shrunk. I bond it over undoped Polyspan.

It is available from Corehouse Models.
Title: Re: SLC OVER Polyspan?
Post by: phil c on March 29, 2015, 07:22:23 PM
A little background on SLC covering.  As Lauri guessed, it is polyester with a fuel proof, heat seal adhesive on it.  It's less than .001 thick, so if the edges are properly ironed down they will disappear.  You can barely see the line and most people can't feel an edge less than .001 or .002in. thick.  The film edge will get buried under primer and paint.  I'd be more concerned about the polyspan edges showing through.  The film is about 1oz/sq.yd.

Doug Moon used it on his Gieseke Nobler ARF's a few years ago.  He and others put automotive paint and clear directly on the film with good success.

After six or seven years of leaving planes in the car for a week some of them have developed bubbles on flat balsa sheet sides.  They can be ironed back down without hurting the paint.

The website, sadly out of date, has info or send me an email.  home.earthlink.net/~philcartier
A 10-12ft sample is $6, prepaid.  100ft x 15.5in. roll is $35 plus $6 or USPS Priority mail and $1.25 for PayPal if you don't want to prepay by check or MO

I can't take credit cards at the moment.  Visa screwed me out of a goodly sum on a processing error, so I'm looking for alternatives.
Title: Re: SLC OVER Polyspan?
Post by: dennis lipsett on March 29, 2015, 11:45:01 PM
So, what brave soul will be the first to try this? It REALLY works.

Larry this is not a new process. I have covered like that on several occasions for years and yes the film will stick tenaciously to either silkspan or Polyspan. You also get a side benefit in that you can put the film on in pieces to achieve a complex color scheme by doing this method. picture of my walt Umland Edge 540 will show you that it is a completely viable solution. Each piece of the wing/tail design was cut separately and applied. Your also right in that the method gives incredible torsional rigidity to the wing
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on March 30, 2015, 08:21:04 AM
Wow! Very spectacular decor. Thanks for showing it. CLP**
Title: Re: SLC OVER Polyspan?
Post by: Steve Thornton on April 24, 2015, 05:22:43 PM
Thanks for the great thread Larry.  I'm ready to cover my Baby Flite Streak, and need a bullet proof plane to learn to fly inverted, so I am covering with your method and have 2 questions:
1. At what stage should I apply Super-Fil for the fillets...before or after I cover the wing?
2. What size tank should I use for my Norvel Big Mig 061?
I always learn a lot from you guys!
Steve Thornton
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on April 27, 2015, 09:01:42 AM
I would do the fillets after the Polyspan but before the SLC.

A 1 ounce tank should do.
Title: Re: SLC OVER Polyspan?
Post by: Steve Thornton on May 09, 2015, 02:52:56 PM
Larry just one more question, what method did you use to apply the  Polyspan?  Did you use dope or Balsarite or stix-it?  Thanks again for this post it's a great idea.
Steve
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on May 10, 2015, 05:12:10 PM
Go read reply number 6.

Yes, I'm mean and nasty in my old age. VD~ VD~ VD~
Title: Re: SLC OVER Polyspan?
Post by: Steve Thornton on May 11, 2015, 01:57:33 AM
Reply #6  "The only dope used is enough to bond the Polyspan to the wing structure. No dope on the open bays at all!"  Does this mean that the polyspan is not bonded to the ribs?  Sorry if you are getting impatient with these questions, but I don't want to make a mess of a plane I have worked on to be straight and strong.  Doc, I'm not stupid but I'll admit to being ignorant!
Steve
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on May 11, 2015, 11:39:22 AM
I think you don't want the poly-span doped to the ribs.   Might be faster if you send Larry a PM. He is a nice gentleman.


Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on May 13, 2015, 09:27:44 AM
I do dope theribs tomake them smooth, but don't bond the polyspan to them. Some bonding does happen in the heat shrink and SLC overlay process. You want the polyspan to have as much leeway to shrink evenly as possible.

So faras I have experienced, any film covering will work, but you will find major weight and paint adhesion differences.

Hard as it may be to believe, I don't have ALL the answers!   LL~
Title: Re: SLC OVER Polyspan?
Post by: Steve Thornton on May 13, 2015, 11:11:57 PM
Thanks for the work & info Larry.  You have given me a plan & a track to run on.   While you may not have all the answers, you do have a very innovative idea and that's way ahead of me.  I am curious if some Balsarite on the ribs might allow the span to adhere after shrinking & prevent the covering from "floating" while in flight.  It wouldn't add much weight & would add some torsional strength.  I'll give you a report after vacation.
Steve
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on May 28, 2015, 09:13:12 AM
Balsarite should work too.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on June 25, 2015, 11:53:54 PM
Any input from people who have tried this? Enquiring minds want to know, especially if there are issues to be overcome! It works great for me, but I don't do 20 point models.  D>K
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on August 23, 2015, 08:12:05 PM
7000+ viewings, and nobody trying it? Astounding!!! Give it a shot on a junker refit and maybe you will come to love it.  How hard is this?  HB~>
Title: Re: SLC OVER Polyspan?
Post by: Ara Dedekian on August 24, 2015, 07:45:26 AM
A little background on SLC covering.  As Lauri guessed, it is polyester with a fuel proof, heat seal adhesive on it.  It's less than .001 thick, so if the edges are properly ironed down they will disappear.  You can barely see the line and most people can't feel an edge less than .001 or .002in. thick.  The film edge will get buried under primer and paint.  I'd be more concerned about the polyspan edges showing through.  The film is about 1oz/sq.yd.

Doug Moon used it on his Gieseke Nobler ARF's a few years ago.  He and others put automotive paint and clear directly on the film with good success.

After six or seven years of leaving planes in the car for a week some of them have developed bubbles on flat balsa sheet sides.  They can be ironed back down without hurting the paint.


Phil

    Here's what happened to my SLC (???) covered Clown racer built in 2001. The covering is what Steve Sacco used on his combat ships back in the '80's and measures .0015". The paint is System Three Inc.'s line of water based urethane marine paints which was sold by Nelson Aircraft Co. (RC stuff). The Clown spent years in attics subject to extremes of temperatures and over the last couple of years shed its paint. The covering was scuffed with OOO steel wool prior to painting.

    Is the covering a thicker version of SLC? Was the water based paint the problem? I have enough of the material left for one or two more planes and it's so light I'd be tempted to try it again as per Larry's suggestion.

Ara

   

   
Title: Re: SLC OVER Polyspan?
Post by: Rick Huff on August 26, 2015, 05:20:03 AM
My Chipmunk is still looking good after about 1 year.  No problems so far.
Rick
Title: Re: SLC OVER Polyspan?
Post by: Motorman on December 20, 2015, 08:55:54 PM
One thing I don't understand. Do you shrink the polyspan before you apply the SLC or do you shrink them together as you're applying the SLC? How does all that work?

Thanks,
MM
Title: Re: SLC OVER Polyspan?
Post by: Rick Huff on December 21, 2015, 05:06:35 AM
I've done 6 planes with either SLC or Ultracote over polyspan and I've shrunk the polyspan first.  I'm not sure it makes too much difference, though. 
Rick
Title: Re: SLC OVER Polyspan?
Post by: jfv on December 21, 2015, 08:49:18 AM
I tried it out on one of my nostalgia combat designs from the early 60's that I put together for this fall's GSCB meet.  I wanted the doped tissue look but didn't have the time.  Worked out pretty well.  A number of people asked me what I cleared it with.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on December 21, 2015, 09:02:10 AM
I definitely shrink the polyspan first.

That combat job looks great! Imagine what it would weigh and the time and money spent if you tried to get that gloss with dope!  S?P
Title: Re: SLC OVER Polyspan?
Post by: Motorman on December 22, 2015, 12:51:59 PM
Have you tried painting the adhesive side of the SLC?


MM
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on December 22, 2015, 06:33:01 PM
I haven't done it, but the free-flight guys do regularly.
Title: Re: SLC OVER Polyspan?
Post by: Walter Hicks on December 22, 2015, 08:02:08 PM
Larry I am getting ready to cover a Little Jumping Bean wing. I have some Polyspan lite, has anyone tried your method with this?
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on December 23, 2015, 08:26:13 AM
Larry I am getting ready to cover a Little Jumping Bean wing. I have some Polyspan lite, has anyone tried your method with this?

Yes, I have, and it is a great use for the light stuff. Coupled with one of the "park flyer" coverings you get a really light weight, fancy finish.  :!

Here is a sample! The model is the Sky Sport, kitted by RSM and designed for .061 power, though a Tee Dee .049 would do the job on shorter lines.
Title: Re: SLC OVER Polyspan?
Post by: Motorman on January 26, 2016, 09:00:23 PM
Is that Coverite Microlite Transparent Yellow? Website says .6oz sq. yd. and already has color.




MM
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on January 28, 2016, 08:11:40 AM
Yup, Microlite it is.  D>K
Title: Re: SLC OVER Polyspan?
Post by: Motorman on January 28, 2016, 07:24:48 PM
Outstanding, I'm going with Microlite over polyspan lite on my next 575 sq in wing. If you google polyspan lite Larry Davidson's name will come up, great guy to deal with. Tower has the gloss white microlite cheaper than the Coverite site but no other colors. Where do you get your Microlite?

MM
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on January 28, 2016, 07:32:37 PM
I just got transparent red and yellow from Tower. I don't think they like you LL~ LL~

Also transparent blue from Smith Brothers in Reseda, CA. I DON't know if they do web sales.
Title: Re: SLC OVER Polyspan?
Post by: Motorman on February 07, 2016, 10:39:03 PM
ha ha very funny. I see they just got a bunch of colors in with more on the way, good for us. You must have timed it just right, showing out of stock already on trans red & yellow.


MM
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on February 09, 2016, 12:47:40 PM
I am just finishing an RSM Ringmaster. The covering is lightweight Polyspan with white Microlite film covering bonded over it.  So far, so good!

The polyspan was ironed down with Mod Podge. I did find the glue soaks through the covering and needs to be cleaned off the iron occasionally. Acetone does the job.

First photo is the polyspan. You can see that it is way lighter than the regular stuff. Second photo is the finished wing. There is a faint texture to the surface, but it sure is shiny!  ;D

Wow! Eleven Thousand hits on this thread, and counting! The only one I found with more is Bob Hunt's electric twin development thread with Forty-nine thousand hits (something to shoot for, guys!) Y %^@
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on February 10, 2016, 10:33:56 AM
That is sure shiny.   I got some Mod Podge  to use.   
Title: Re: SLC OVER Polyspan?
Post by: Mike Griffin on February 12, 2016, 10:45:43 AM
Larry is definitely n to something here.  I did a test panel a couple of days ago using this method and it appears to be almost bulletproof and very light. 

Mike
Title: Re: SLC OVER Polyspan?
Post by: Motorman on February 12, 2016, 11:56:24 AM
Got some Mod Podge. Looks and smells like a thick pasty polycrylic. I'm doing some adhesion testing. Ironing polyspan over Mod Podge doesn't take as much heat as monokote. I was also able to iron on polyspan over polycrylic painted on bare wood. The third test is polyspan put on by brushing through with polycrylic although it is the heaviest/strongest it came out lumpy. I'll let you know what happens when I try to pull them up.

Also if you're doing the edge and you want to wrap it around you have to apply more Mod Podge to the edge because it won't go through 2 layers of polyspan.

Thanks,
MM
Title: Re: SLC OVER Polyspan?
Post by: Motorman on February 13, 2016, 06:02:04 PM
Adhesion tests are done. A 2" strip was tacked down on balsa and left to hang over the edge for something to pull on.

Mod Podge brushed on wood then polyspan ironed on - Pulled off very easy without ripping the cloth

Polycrylic brushed on wood then polyspan ironed on - zero adhesion

Polycrylic brushed through polyspan - Cloth ripped in half, got some of it to pull off at the edge but balsa came with it, had to be removed with 60 grit sandpaper and it was solid all the way down.

In my opinion Mod Podge is an arts & craft glue that's not good enough for model use.

MM
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on February 14, 2016, 04:46:05 PM
You forgot there was SLC over the poly-span.   
Title: Re: SLC OVER Polyspan?
Post by: Motorman on February 14, 2016, 05:36:30 PM
I don't follow. The glue on the film will hold it to the polyspan but the mod podge is the weak link under it all. If you seal the edges with some epoxy or something it might not give you any trouble.

I like the way polycrylic worked but I think it's heavy. I'm going back to good old Sig nitrate.

MM
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on February 14, 2016, 07:16:36 PM
I agree that Mod Podge adhesion seems a bit weak, but it has proven adequate for me so far. My real complaint is that it soaks through the lightweight Polyspan and sticks to the iron, making it draggy on the tissue.

I have a can of water based contact cement I want to experiment with.  Anyone tried that stuff?
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on February 20, 2016, 09:37:15 PM
See the finished model in the main forum.  ;D #^ H^^ CLP** j1 **) (PE**) o2oP DV^^
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on February 21, 2016, 02:28:31 PM
I agree that Mod Podge adhesion seems a bit weak, but it has proven adequate for me so far. My real complaint is that it soaks through the lightweight Polyspan and sticks to the iron, making it draggy on the tissue.

I have a can of water based contact cement I want to experiment with.  Anyone tried that stuff?

Yes, it is just as bad.  Have to clean the iron every so often.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on March 18, 2016, 09:44:32 PM
Lucky me, I flamed out in the four leaf clover and slid in inveted on asphalt. Lots of rework needed on the canop and rudder, but only a barely discernable scuff on the covering! YAY!
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on July 02, 2016, 06:40:57 PM
My Ringmaster has been to hot flying fields for several months now, and the covering is still taut! Nary a wrinkle.   ;D. Looks good as new too. Plus the water slide inkjet decals are still perfect.

You got to try this!
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on July 06, 2016, 10:10:46 AM
Larry, my next plane is going to get this treatment.  Thanks.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on July 06, 2016, 07:06:19 PM
About time!  VD~  mw~  #^ ;D
Title: Re: SLC OVER Polyspan?
Post by: Motorman on July 17, 2016, 10:16:56 PM
Well it works, couldn't believe how light and strong this came out. I want to strip the monokote off my other airplanes.

3 coats of Nitrate thinned 50/50 (could have used 2) then polyspan lite put on with 10% nitrate 90% thinner. Shrink with heat gun then applied Coverite Microlite white. 

Everything went pretty normal, no weird problems and it stays tight in the hot July sun. I did the wing and tail surfaces, the fuselage is just Sig butyrate white on bare wood sparingly.
 
(http://i889.photobucket.com/albums/ac93/giffy6/100_0475.jpg) (http://s889.photobucket.com/user/giffy6/media/100_0475.jpg.html)

MM
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on July 20, 2016, 04:23:45 PM
Looks great! Is that a Pathfinder?  H^^
Title: Re: SLC OVER Polyspan?
Post by: Motorman on July 22, 2016, 10:35:22 AM
It's mostly a TunderGazer.
Title: Re: SLC OVER Polyspan?
Post by: Fredvon4 on July 22, 2016, 11:21:44 AM
Getting ready to put 8mm blue silk on a Pat Johnston S-1 (ish) Ring Master wing for a plane I hope to keep under 26 oz

Does anyone think the SLC ( I have plenty of) is a good idea on top to keep from dope, dope, dope weight adding?

And if so-- should I put ANY dope ( perhaps one cote of tautening) on the silk panels first?

Remember the RM is a polywog rib set
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on July 24, 2016, 08:00:24 AM
one very thin coat of taughtining dope might be good. You do NOT want to fill the weave or you will get bubbles of un-attached film. Definitely be sure the silk is well adhered to the ribs.

Let us know how it comes out, and show photos!  H^^
Title: Re: SLC OVER Polyspan?
Post by: Motorman on July 24, 2016, 10:03:38 AM
Fred check out Coverite Microlite, it comes in colors. If your silk comes out really tight you could coat it dry.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on August 14, 2016, 12:43:50 AM
Today it was over 90 deg. out, and still no hint of slackness or wrinkles in the covering. The plane was left in full sun, not hidden in the tree shade at Whittier Narrows. ;D

That is at least 6 days in the sun, now.

Oh, btw I scored 444.5 in Old Time. That's the good news. The bad news is that was only good enough for fourth.  HB~>
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on September 22, 2016, 05:00:40 PM
Nearly 18,000 views and two guys have tried it? What is so hard? Buid a Brodak 1/2 A ARF Clown and try it out.

A: It is a fun plane to own. ( Cox, Norvel, Brodak and AP Wasp all fit, saw off the nose and add a firewall for Cox reed engines, surely you have ONE of the above?)

B: It is quick and cheap. 35 ft Spiderwire lines and an 1/8" ply handle with 2" line spacing certainly won't break the budget.

C: If it sucks,you can strip it easily and do something else. Not like 6 months doping and polishing for appearance points were at stake.

Come on, where is your sense of adventure?
Title: Re: SLC OVER Polyspan?
Post by: Vincent Judd on October 01, 2016, 08:45:49 AM
I wanted to try this on the fuselage of my new Crossfire.  I'm just wondering, since it's all balsa, no open bays like a wing surface, do I gain anything by using the Polyspan under the SLC covering or can I just use the SLC and then paint it?  Thinking about the weight savings by just going with the SLC.

Thanks
Title: Re: SLC OVER Polyspan?
Post by: jfv on October 01, 2016, 10:11:10 AM
Although I posted a photo of my finished Berekely Lancer in the Build Section, I thought I'd also post it here.  Wing is finished with SLC over polyspan.  It came out beautiful.  I'm really getting to like this method for my sport planes with open bay wings.  Fuse and tail feathers were painted with Duplicolor Paint Shop and cleared with 2 part auto. 
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on October 02, 2016, 07:02:09 AM
WOW! Nice.  y1

I think just SLC alone on solid wood parts is all you need.
Title: Re: SLC OVER Polyspan?
Post by: Vincent Judd on October 02, 2016, 09:59:07 AM
Although I posted a photo of my finished Berekely Lancer in the Build Section, I thought I'd also post it here.  Wing is finished with SLC over polyspan.  It came out beautiful.  I'm really getting to like this method for my sport planes with open bay wings.  Fuse and tail feathers were painted with Duplicolor Paint Shop and cleared with 2 part auto. 

That is a beautiful finish.  Can you give more detail as to how you achieved it?  How did you prep the fuse and tail feathers?  Which 2 part auto clear did you use?

Thanks,

Vince
Title: Re: SLC OVER Polyspan?
Post by: jfv on October 03, 2016, 04:30:27 PM
Vince:

Fuselage and tail feathers were finished with nitrate, carbon veil, then several coats of Eze-kote finishing resin (http://www.horizonhobby.com/eze-kote-finishing-resin--500-ml-dlmbd37) followed by Duplicolor rattle can gray primer.  Color was Dupli-Color Paint Shop lacquer paint then the 2 part auto clear coat.  Clear is ACL-7200-5L by Axis performance coatings.

The Eze-kote is similar to water-based poly but cures much faster and sands very nicely.   
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on November 17, 2016, 11:31:23 PM
 How did you do the decals? That is a great looking model!

What prep did you do for the paint over SLC?  ???
Title: Re: SLC OVER Polyspan?
Post by: Dane Martin on November 18, 2016, 08:34:34 AM
Although I posted a photo of my finished Berekely Lancer in the Build Section, I thought I'd also post it here.  Wing is finished with SLC over polyspan.  It came out beautiful.  I'm really getting to like this method for my sport planes with open bay wings.  Fuse and tail feathers were painted with Duplicolor Paint Shop and cleared with 2 part auto. 

Omg that looks amazing!
Title: Re: SLC OVER Polyspan?
Post by: Fredvon4 on November 18, 2016, 09:10:15 AM
Yes it does...

I usually hate cloth hinges but those blended in very well

Starting to get enough dry air days here to try my hand at a SLC over silk or poly wing

This Lancer inspired me to get things set up
Title: Re: SLC OVER Polyspan?
Post by: jfv on November 18, 2016, 07:08:02 PM
Decal was made on my vinyl cutter.  Scanned the image, traced it in AutoCad, then cut it out with the cutter.  It's all about the tools you know!
Title: Re: SLC OVER Polyspan?
Post by: jfv on November 18, 2016, 07:12:09 PM
Although you can paint directly over the SLC, I didn't want a ridge where the SLC ended so I covered the portion I was going to paint with carbon veil adhered with Eze-Kote.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on November 19, 2016, 08:37:10 PM
Ummmm, did you then sand a taper down to the SLC surface? I am not clear on the exact process. It looks like you have a winner, though. Please detail it out step by step for those of us of feeble brain (see Winnie thr Poo for reference). I want my next one to look that good!  #^
Title: Re: SLC OVER Polyspan?
Post by: jfv on November 21, 2016, 10:48:44 AM
Applied the CF veil, then several coats of Eze-kote, sanding between coats until smooth.  Primed with DC-540 primer with the rest of the parts to be painted, then color coats.  The ridge between the painted surface and the clear SLC film is at the red pinstripe line and not very noticeable.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on December 30, 2016, 01:13:34 PM
What is EZ-Kote? I never heard of it.  ???
Title: Re: SLC OVER Polyspan?
Post by: Brent Williams on December 30, 2016, 05:17:29 PM
What is EZ-Kote? I never heard of it.  ???

https://www.deluxematerials.co.uk/gb/rc-modelling/82-eze-kote-5060243900746.html (https://www.deluxematerials.co.uk/gb/rc-modelling/82-eze-kote-5060243900746.html)

It's a pretty cool water based finishing resin.  It is not like Minwax Polycrylic.  The viscosity is thicker and it dries quite rapidly.  Sands well too.  It smells totally different from polycrylic, also.

There are some good videos of it in use on youtube. 
Title: Re: SLC OVER Polyspan?
Post by: Steve Helmick on January 09, 2017, 03:15:40 PM
I see that Horizon Hobby is a distributor, which implies that virtually any LHS should be able to get this stuff, or we can order direct from HH. So, I assume that Brent has used this stuff already? Has Gordy D. or Norm W. tried it? I noticed that they said "fuel resistant" and that does concern me a bit. I'd prefer "impervious", ya know!  ~> Steve
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on March 27, 2017, 08:22:51 PM
My Ringmaster is now over a year old and still sag free!  :)! No hangar rash or noticeable damage from two (count them, two) inverted landings on asphalt. (Note that I am Designman, not Pilotman)  LL~
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on March 28, 2017, 11:10:12 AM
Well Larry, I haven't had a chance to try out my planes with the dopeless finish. 
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on March 28, 2017, 09:48:22 PM
And you continue to live in a climate like that??? Well, The Peoples' Republic of Califonikstan is crowded enough, but there is lots of room left near Tucson. Trostle left a magnificent house there.  <=
Title: Re: SLC OVER Polyspan?
Post by: Jim Roselle on May 13, 2017, 08:42:49 AM
Larry,

I'm getting ready to try monokote over polyspan. Do you dope the poly to individual ribs or just leading/trailing edge, tips, and center section?

 Jim
Title: Re: SLC OVER Polyspan?
Post by: Fredvon4 on May 13, 2017, 09:55:35 AM
Jim... just a butt inski here...but WHY?

Maybe I am not paying close enough attention

BUT--- I thought the exercise was to do a Fast and very Strong covering method--- USING poly/tissue/silk and then--- one of the super lite plastic coverings Like SLC, or thin FasCal/ mica film

IMO MonoKote---  or similar--- has already all the strength and color needed by it self

That said...I think the initial covering (tissue/poly span/silkspan/silk) is put on traditionally nice and tight on the perimeter and only ever needs stuck down to the ribs on a polywog rid set like a Ringmaster....all other rib types should be left free so the SLC/////ect,...can shrink and stick to the first covering without adding torque to the ribs or balsa wing

I use a lot of Poly span and silk on wings.

I think Larry Renger found a way for US to NOT have to add weight with Dope and Use the Lite coverings  (SLC/Doculam/FadCal) as the shiny top cote and the added benefit ...by accident...was that the composite of the two coverings saved time, looked good...and structurally was tougher than traditional method using dope to fill the paper/tissue/cloth

Bottom line is...IMO MonoKote covering does all this by itself.... But that said--- no MonoKote can look or be as strong as a traditional silk n dope method or Larry Rengers discovery method

EDITED in after sending...Jim I DO NOT intend this to sound as harsh or judgement as it does....

Just curious how you arrived at following this method to think about using MonoKote over something else.... mostly because early on, I GOT the notion Larry was trying to show four things...Light weight, faster, looks good, stronger (an accidental by product IMO)

And BTW
NOT TO take away from Larry-- But I think Bobby Mears, INDEPENDENTLY--- found a very similar method so he could rapidly finish dozens of Nostalgia combat planes for the Combat Museum...IIRK He experimentee with fogging the back side of SLC/FasCal/Doculam with paints to simulate the Silk n Dope finish and found it was just as easy to do a polyspan heat shrunk and then the plastic and looked just like a silk n dope finish
Title: Re: SLC OVER Polyspan?
Post by: Jim Roselle on May 13, 2017, 12:59:56 PM
Fred,

I want to try this for three reasons.

 1. Primarily I'm hoping that by creating a composite covering that bonds together as it shrinks I can avoid the dreaded monokote sag that happens in the Arizona sun.

 2. It seems like a great way to add strength with minimal weight gain and minimal additional time.

 3. I'm always up for experimenting with new techniques.

Jim
Title: Re: SLC OVER Polyspan?
Post by: Fredvon4 on May 13, 2017, 01:55:06 PM
Fully understand Jim....you are trading strength and durability for tightness and accepting the weight gain...

I might recommend Move on to Ultra kote as I think it holds it's tension better long term...I am in Texas with 130~150F on a 104F OAT day in the car is typical and the loosening of my films....all of them...is always an issue


OTOH I have read here that some think UltrKote is looser over time....not my personal experience but I only have 5 years experience/history to go by
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on May 14, 2017, 08:50:38 PM
Jim, if you want color go browse the posts I have made using poly-ester cloth(from Jo-Anns Frabrics) and the clear mylar(SLC). 
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on May 17, 2017, 12:30:30 PM
Doping the ribs to smooth them out is good. Bonding the Polyspan to the ribs (when first covering) is bad because you want the material to slide around as it shrinks. Once shrunk, if you seal to the ribs using thinner would probably be OK and might improve torsional strength.  Do NOT dope the entire fabric covering as it adds weight and creates bubble areas in the top covering.

Old free-flighters may remember double covering large models. Silkspan lightly doped with an overlay of Japanese tissue bonded down to it. Easy to get a slick finish and remarkably strong.

For large models, Monokote over Polyspan would still be lighter than a conventional dope finish, easier, quicker, slicker (than I can do, anyway) and way stronger.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on July 03, 2017, 03:07:48 AM
I finally completed the re-build of my Sky Sport 1/2A (well, .061) stunter. The wing is the original, everything else is new.

Covering is lightweight Polyspan with park flyer type film applied over it. The Polyspan was attached with Mod Podge adhesive and the film has its own heat activated adhesive, so no dope was harmed in covering the wings.

Fuselage and tail are Klasskote epoxy.
Title: Re: SLC OVER Polyspan?
Post by: jfv on July 03, 2017, 07:59:21 AM
Very nice.  I like the transparent color.
Title: Re: SLC OVER Polyspan?
Post by: PaulGibeault on August 08, 2017, 12:05:08 AM
Following along Larry Renger's simple instructions I covered 2 old Vintage kits. I haven't covered an open bay model for over 25 years. Piece of cake!(http://)
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on August 08, 2017, 10:33:21 AM
I am finishing up two more models per Larry's method.  Have also flown the ones I have finished.   Makes for quick finishes that shine.   Also easy to wipe clean.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on August 16, 2017, 09:04:46 PM
Paul G. built those models for his wife to learn on. So far the covering has proven more durable than other parts of the models.  LL~
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on November 02, 2017, 11:53:46 AM
Hoooee! 32,000 + views!  ;D

 There aren't that many CL fliers, are there?  ???
Title: Re: SLC OVER Polyspan?
Post by: Fredvon4 on November 02, 2017, 12:33:12 PM
Crap Larry.. I bet I am about 500 of those 32000 views....grin

I found i interesting in another thread on MonoKote that the very early instructions suggested/recommended the $Kote film OVER silk-span


Title: Re: SLC OVER Polyspan?
Post by: MikeyPratt on November 02, 2017, 08:56:39 PM
It works fantastic!  The weight, by an actual test sample, is 1.46 oz/sq.yard.  The structural rigidity it adds is amazing.  I have some technique to work on as far as flawless tips, but the ones I did aren't horrible.

Now I need to work on how to properly paint it.  I have a sample piece drying. It is Painters' Choice right on the steel wool buffed SLC.

Larry,
Works like a champ doesn't it?  Next time add some trim to the plyspan before covering it with SLC.  Use a spray adhesive and very lightly spray the back of the trim.  Stay away from the trim 3 feet and spray above it and allow the adhesive to lightly fall onto the trim.  Place the trim on the plyspan and lightly rub the trim in place (do not apply dope to the trim).  The SLC will hold the trim in place when ironed on.

Later,
Mikey
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on November 02, 2017, 10:14:38 PM
Great idea on the trim! Thanks Mike. Probably could do trim Moneykote, vinyl, or just about anything. Magic markers, anyone?
Title: Re: SLC OVER Polyspan?
Post by: Ara Dedekian on February 25, 2018, 10:41:35 PM


        Rebuilt an old silkspan covered Scorpion fast combat and covered it with SLC over Dacron. I used John Holiday's Mod Podge system to iron down the Dacron then used it to recoat the leading, trailing and tip edges for a belt and suspenders approach to ironing the SLC on. The yellow paint is an anxient can of Formula-U over sprayed with green RC car paint. The urethane stuck to the SLC quite well but don't have much hope for the  'candy' accent.

        Ara
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on February 26, 2018, 11:06:35 AM
Just don't let the raw fuel sit on the graphics too long.   Plane looks great. H^^
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on August 11, 2018, 04:59:53 PM
Several years and a couple of trips to Tucson later, the Ringmaster still looks pretty good. Anyone else have information on how well this technique stands up to the ravages of time?
Title: Re: SLC OVER Polyspan?
Post by: Motorman on August 11, 2018, 05:12:21 PM
My white Thundergazer is still perfect.
Title: Re: SLC OVER Polyspan?
Post by: Fredvon4 on August 12, 2018, 11:53:59 AM
Larry I basically no longe fly so my Fleet are all now you basic hanger queens hoping my progeny will some day fly again

I have several RST foam wing with SLC....flown and castor slime many times...cleaned and in flyable condition

I have two balsa wings, Ring master, and a Magician Poly-span adhered with dope then heat shrink, then SLC from Phil...NO fill in dope...strong, no sag, look pretty good for my 5 meter stand off grading......grin...

I bet when I crap out ...my son, just for pure nostalgia will de gum the engine..and fly the sucker into a perfect Figure Nine....Just as I did reliving the adventures of my father and me for 1958
Title: Re: SLC OVER Polyspan?
Post by: MikeyPratt on September 13, 2018, 11:25:42 AM
Hi Guy's,
I had a real problem covering my new P-Force XL.  I applied the red plyspan tissue to the model, then covered the model with the SLC and it looked AWESOME.  I manage to stick the end of the inboard wing into a running overhead ceiling fan and destroyed the wing tip, leading edge sheeting, and three of the wing ribs.  When I was inspecting the damage I noticed the tissue under the SCL wasn't attached to the cap strips.  It may have been good enough but I wasn't happy with it at all. 

After stripping the wing and repairing the damage area, I opted for UltraCoat covering to finish up the model.  On my next model I'll apply a few coats of Stix-it to the capstrips and cover it using plyspan tissue and after applying the SLC, I'll rub the SLC to each of the wing cap strips with an iron.  This should attach the plyspan and the SCL to each of the wing ribs and greatly increase the strength of the wing covering.

Later,
Mikey
Title: Re: SLC OVER Polyspan?
Post by: jfv on September 13, 2018, 11:43:28 AM
I use Baslarite on the rib edges when I cover with the Polyspan just for the reason you mentioned.  No issues doing it that way.
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on September 13, 2018, 08:38:12 PM
I don't recommend doping the poly-span/silk span to the ribs.   I do shrink it before putting the clear mylar/SLC on.   so far the covering has stayed tight and several places it looked like some thing tried to poke holes in it.  A pass with the iron and all is good.  Latest plane still looks good and is the one I'm building a stooge for.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on September 25, 2018, 04:22:26 PM
I have recently been experimenting with turbulators (or vortex generators). I find that I must sand the film with 600 grit then clean it with lacquer thinner or acetone before bonding the generators in place. Otherwise, they eventually pop off.  HB~>

Sand carefully, that film is THIN!  n1
Title: Re: SLC OVER Polyspan?
Post by: jfv on September 26, 2018, 07:39:49 AM
Here's my latest build using SLC over Polyspan.  I really like using this method for these type planes.  Saves tons of time and looks great.  The "Able" is one of my original designs from 1960 when I was in high school.  Flew it at the Vintage Combat Festival last Sunday.
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on September 26, 2018, 10:26:13 AM
Looks great.  Do you have plans.  Also you should do an article and publish it. H^^
Title: Re: SLC OVER Polyspan?
Post by: jfv on September 26, 2018, 10:53:57 AM
Thanks, Doc.  It flies great.  Yes, I have the plans.  Here's a copy.
Title: Re: SLC OVER Polyspan?
Post by: Frank Imbriaco on September 26, 2018, 05:32:06 PM
Jim's ship is really very, very nice.
I especially like the tail feathers.
Saw it fly at the Vintage Combat Festival and it was very impressive.
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on September 27, 2018, 09:38:25 AM
Thanks, now to head for Staples. H^^
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on October 18, 2018, 09:26:51 PM
My Ringmaster is 5 years old. It has a couple of slit punctures and tip abrasions. I am thinking of a complete recovering job. Same routine as originally done. Lightweight Polyspan with parkflyer film overlay. Maybe Japanese tissue? Or ďDoctor PaperĒ. Any thoughts out there on the choices?

The rest of the plane is Klass Kote epoxy, and no fuel soaking noticeable. Of course it may be a soggy mess under the Epoxy and no way to know it until the engine departs for the hinterlands.

Current power is an ABC L&J Fox 35. Just perfect power for the 29 ounce model. 10x5 Brodak Prop. 3 ounces for the OT pattern with laps to spare. .012 x 50í lines and my EXPO, low overhang, hardpoint handle. Took 2nd behind John Wright (Gee, what a shock!) at the Hy Johnson meet last week. 2nd flight run was beautiful 2-4 break with no Fox burp.

Donít need no stinkiní modern engines! (Actually, my FP 20 seems to be a better choice, but one must be loyal to the Duke!)

Plenty of kits for the handle left (blatant commercial inserted).  ;D
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on November 15, 2018, 09:36:13 PM
Dang, after 5 years of mistreatment there are some scrapes and holes in the Ringmasterís covering. I may strip it and redo, or put clear tape over the breaks.

The fuselage has been broken behind the wing courtesy of three different people stepping on then kicking my lines at VSC this year. (Hmmm, enemy action? Canít believe I am good enough to warrant it.) Plus a couple of inverted landings. It ainít a virgin no more.

My ABC Fox 35 gives a great 2/4 performance. 2 3/4 ounces of fuel for the OT pattern. 10x5 Brodak prop, 10/22 fuel. Currently flying 50x.012 lines, but may try longer lines with a higher pitch prop. Then pick up the nitro as needed to keep up the lap time.

Still weighs under 30 ounces even with an ounce of tail weight. Epoxy basecoat on the fuselage nose and Klasskote finish, so no oil soaking. Carbon fiber veil on the fuselage and horizontal tail. Pinned hinges aligned with a single wire. At rest the elevator just flops right down. No apparent friction in the system.

Sadly, my Ceramic Fox crankshaft broke the crankpin off, so it needs a rebuild. Ty Marcucci sent me a complete engine, but it is so cherry that I canít bear to strip it for the crank! A good machine needs the respect it deserves!

Thanks to Andy Borgogna, I have an even lighter Ringmaster with an OS20 fp to fly. So I can strip mine and rework it at my leisure.

Sadly, Andy has Rotaror Cuff problems that will keep him from CL flying in the future. A sad state of affairs, but he will still be with us flying (gasp) RC. And he will still be a resource as the West Coast electric power guru. I still think he could fly 1/2A models without pain, but no luck so far.

The SkySport covering is still in great shape. This technique seems to be really durable.

Anyone done a painted finish on SLC over Polyspan and how did it come out and last?
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on December 01, 2018, 08:56:29 PM
Wow, pushing 38K hits! Whoíd a thunk it! Now, how many are using this system other than Doc Holliday and me?

Multiple models show that the system works great. Donít just read about it, use it and tell of your experience and especially any improved techniques.

So far, Mpd Podge for initial fiber covering adhesion, followed by SLC or Park Flyer film is great for most models. I havenít tried it, but for a larger model, Silk and Monokote ought to be pretty bulletproof,

The key to this system is that the film bonds to the fiber making a strong composite structure that is stronger and lighter than a conventional dope filed  finish. If you plan to paint, it eliminates all the filler coats. One light roughing with steel wool and ready for primer or silver under base.
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on December 02, 2018, 07:31:13 PM
For get the steel wool, use a scouring foam pad.  At least that is what I'm using now. D>K

Just wanted to show my latest finish on sport planes.   Did use epoxy around the engine compartment.   No dope,  doctor paper under the laminate clear.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on December 04, 2018, 06:32:28 PM
i have some Doctor paper, but havenít used it except for dry balsa covering, never open bay. It does have wet strength, but does it wet shrink? How good it is a replacement for old silkspan?

Your wing tips look perfect, does it conform wet or do you use separate tip strips? Tell all!
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on December 04, 2018, 08:49:15 PM
Larry, I tried to apply doctor paper slightly damp the first time I had it.  What a mess.  Using the Mod Podge I put it on dry and it does shrink some after applied. D>K
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on December 08, 2018, 05:58:59 PM
I have a Ringmaster and a SkySport both covered in film over Polyspan. Both years old and still in great shap despite abuse!  #^
Title: Re: SLC OVER Polyspan?
Post by: Target on January 05, 2019, 12:18:05 PM
Hi, Larry-
Thinking ahead towards finishing a Magician for a buddy I am building, I am wondering about getting trim colors onto the finished product without painting. Essentially, I want it between the polyspan and the SLC layer.
I am thinking two ideas-

1. Polyspan covering, then colored tissue in my trim color areas, then SLC.

2. Polyspan covering, then transparent or opaque film covering in my trim covering areas, the SLC over.

Any commentary for either of these ideas? Have you done this before? I would love to use the tissue, but I am concerned about the dope or other material needed for attachment causing bubbles under the SLC when heated.

Thanks,
Target
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on January 05, 2019, 02:31:27 PM
How about a light spray of spray adhesive on the back of the tissue? No dope, just enough to keep it in place while doing the SLC.
Title: Re: SLC OVER Polyspan?
Post by: Target on January 05, 2019, 03:30:36 PM
Ok, i hadn't thought of that, thanks. Would the Modge Podge work as well?
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on January 05, 2019, 05:09:04 PM
Being water based, I think it would distort the tissue decorations.
Title: Re: SLC OVER Polyspan?
Post by: Target on January 05, 2019, 08:14:35 PM
Ah ha....
OK thank you Larry!!
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on March 05, 2019, 07:49:16 AM
[quote

Hi, Larry-
Thinking ahead towards finishing a Magician for a buddy I am building, I am wondering about getting trim colors onto the finished product without painting. Essentially, I want it between the polyspan and the SLC layer.
.

Thanks,
Target
[/quote]

You are building a buddy?  LL~
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on April 14, 2019, 08:55:24 PM
I have done colored parkflyer film over Polyspan with great, long lasting results.  ;D

I was wondering if anyone went the next step and applied a paint finish over the laminate? With proper scuffing of SLC, it is supposed to take paint just fine. I think I read of someone painting directly over the film without the fiber underlayer.

Input? Anyone?  ???
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on April 15, 2019, 10:22:18 AM
Yes, buff the SLC surface to a dull texture.   No sheen anywhere you want paint. D>K
Title: Re: SLC OVER Polyspan?
Post by: phil c on April 17, 2019, 11:57:15 AM
Sounds like a great way to cover a model.

What I don't understand is how do you keep the overlap from showing when you paint?

Or do you do both top and bottom together?

If you take the time, seal the edges by sliding/rolling the iron across the top layer edge to really seal it down.  The covering is less than 1 mil thick.  very few people can reliably feel that, and only with soft, clean fingertips.  Seal the edges with primer and sand the edges smooth  before finishing the prime.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on April 22, 2019, 07:31:38 AM
The upshot of,this,is that SLC over polyspan is lighter, tougher and quicker than a dope finish. No pre doping the framework, if you use Mod Podge. Wrinkles eliminated with a hot iron.

The whole process is water based, indoor, no smell. Also, probably less expensive and way less time consuming than multiple coats of dope with proper drying time.

Color can be dyed into the tissue, or sprayed onto the back of iron on film, or the film can be the color.

If you want a conventional finish, roughen the SLC  with a Scotchbrite pad before application, cover as usual (with SLC over tissue) And go directly to your base color or blocking color.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on August 03, 2019, 08:21:07 PM
My goodness! Over 41,000 hits on this string.

So who else besides Doc Holiday and I are actually using this process?

Speak up!
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on August 04, 2019, 04:24:11 PM
I too am surprised not more people have tried this.   Even Sandy the poodle likes the shop not having the dope smell as well as the thinners and cleaners. D>K
Title: Re: SLC OVER Polyspan?
Post by: Motorman on August 04, 2019, 09:31:38 PM
As in post 95, I do my own version with Microlite over polyspan lite. It's lighter and I don't have to paint it. Just did a Twister wing in transparent blue. Over lapped the open bays 1" using minimal nitrate dope as glue.


Motorman 8)
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on August 05, 2019, 07:35:46 AM
Nice job!

I also used Microlite on my Ringmaster an SkySport models.
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on November 02, 2019, 07:57:43 PM
At the AMA EXPO, the guy in the free-flight booth was covering his model with wet tissue. It turns out to be Esaki tissue. Amazingly, it is about as light as Japanese tissue!

I plan to try it instead of Polyspan on my next model under SLC! Lighter is good!  ;D
Title: Re: SLC OVER Polyspan?
Post by: Motorman on November 02, 2019, 08:43:15 PM
I didn't know what Esaki was but, I found this info.

Esaki tissue has its drawbacks as well. This tissue fades quickly in the sun and can shrink a great deal. Usually the shrinkage occurs in one direction and the results can often be extreme.


Motorman 8)
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on February 17, 2020, 07:50:45 PM
I blush to admit that the Klaus Kote epoxy is not adhering to the park flyer film near the fuselage of my Sky Sport. Mind you, this is after several years of flying it.

What results have the rest of you gotten painting over film?
Title: Re: SLC OVER Polyspan?
Post by: Dave Hull on February 18, 2020, 01:27:52 AM
Larry,

When I use MonoKote over the flying surfaces and KlassKote on the fuselage, I generally try to overlap with the paint at least a 1/4". Often, I paint further over the plastic for a scallop paint job. I have not noticed any adhesion or separation problems yet. (Maybe I'd better go look closer?)  Some of these paint jobs are 10+ years old now.  I do prep the plastic for paint by masking my paint line, then scuffing up to it with gray Scotchbrite followed by a wipe down with alcohol. This truly gets it clean, and gives more tooth for the paint. I prefer not to use KK primer over the plastic.

Dave

PS--We were all impressed by your flight on the 1/2A on Sunday. The vertical eights had three or four of us talking....
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on July 11, 2020, 08:37:04 PM
Anybody new trYing this? And how is it working out for you?

A local flyer has silkspan over SLC and it it OK, but not as nice as if he Had done the other way. Rough surface, and of course subject to fuel damage.
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on July 12, 2020, 12:37:35 PM
I've finished several planes now with the new process.   As an exoeriment I put super Monkote over the doc paper..  Good on wings but won't do it again on the fuse. D>K
Title: Re: SLC OVER Polyspan?
Post by: L0U CRANE on July 12, 2020, 05:50:33 PM
Just an odd -tangential - thought...

About 40 years ago, I did an All American, Sr., as follows. Stock wing structure (C-TUBE. plenty strong.)  Clear Monokote on the wings. May have buffed the surface lightly with green Scotch-Brite (3 days old to reduce the 'cutting' surface.) Thorough wipe with straight Acetone, and care to NOT touch the surface with oily fingers before a light dusting with clear (btw, classic, i.e., pre-EPA,  AeroGloss, which I miss very much!)

Wipe with isopropyl alcohol and 'no-touch' care before color coats, 'plasticized' of course - a few drops of castor per ounce. Seemed to last, not compromise the Monokote strength, and needed nothing more to make a durable, NICE finish. No edge seeping, no separations. Seemed light! No numbers on that, but back then, few if any troubled to do that.

Not so much on that AA, Sr., but noticeable on a few later planes - masking the trim was a gamble. Adhesion against normal wear and tear was fine, but lifting  the masking tape off was chancy. (I learned that 'breaking' the sticking power of even low-tack mask by laying the sticky side along my forearm before applying it to the mode, helped. Did not cure it. No hair on the 'bottom' of my arms, so no pain. H^^ )

Anyway, that AA, Sr., lasted several years, and even survived quite a bit of experimentation. E.g., tried a  left-hand shaft Fox 35 (factory shaft, -then.) LH - or "pusher" props were available in many sizes, again, - then.

FYI - engine flew identically as with stock RH shaft, and was converted after many hours as stock. Only difference noted, other than punching the pavement during starting, was MUCH easier takeoffs (it didn't turn in, or droop the left wing from torque.) If tipweight were adjustable, I could have removed most, or all, of it. (Favorable torque...)
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on September 15, 2020, 05:33:42 PM
Has anyone used this technique on a (shudder, gasp) RC model? Dare we let the DARK SIDE know? ???
Title: Re: SLC OVER Polyspan?
Post by: Ara Dedekian on September 15, 2020, 07:24:48 PM
Has anyone used this technique on a (shudder, gasp) RC model? Dare we let the DARK SIDE know? ???

     RC assist 1942 Michael LaTorre Alert. Rear Fuselage is SLC over dress shop Dacron/Rayon.

     Ara
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on September 16, 2020, 08:29:29 AM
Nice! I love the exhaust routing! No mess!    H^^
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on November 04, 2020, 05:47:51 PM
OK, we have had a number of success stories, has anyone encountered problems and can offer solutions?

My only difficulty was inadequate prep in painting over the film and having the paint peel off. An easy fix with an Acetone wipe, proper abrasion and repaint.

Actually, also, adhesion problems for my turbo generators, they tend to pop off and get lost. (cheap, short sections of HO GAGUE plastic extrusion, so no big deal)

I have found the covering extremely resistant to damage from mistreatment (inverted landings under power on asphalt)  :-[

Also, pretty good at resisting temperature changes, though not perfect.

What is your experience?

Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on November 05, 2020, 10:45:56 AM
Only problem really is keeping APC props from poking holes.  I do have one that needs refinishing as the paint(Rustoleum) is peeling off.  I think the NAPA Primer is the problem. D>K
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on January 08, 2021, 08:49:40 PM
We are getting a lot of hits on this thread recently! I love it. But is anyone actually using the technique? And would they please show and tell here if they are?
Title: Re: SLC OVER Polyspan?
Post by: 944_Jim on January 08, 2021, 09:06:00 PM
Good on wings but won't do it again on the fuse. D>K

I'm intrigued by this process.
Why not the fuse please?
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on January 09, 2021, 11:44:04 AM
Yes, I have done fuselage.  Go read the posts in the finishing section. D>K
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on January 10, 2021, 08:42:40 AM
Which post Doc? There are an awful lot of them.
Title: Re: SLC OVER Polyspan?
Post by: Tom Luciano on January 10, 2021, 03:59:27 PM
Larry,
  Is there a new source for SLC?
I didnt think Phil was getting anymore.

Tom
Title: Re: SLC OVER Polyspan?
Post by: john e. holliday on January 10, 2021, 04:36:05 PM
Which post Doc? There are an awful lot of them.

As lazy as I am and you want me to go look.  It would have to be last year or late 2019. D>K
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on January 10, 2021, 05:59:09 PM
I looked at the last four pages for your posts and missed seeing anything. It would have to be imbedded in another thread.

So, what was the problem with doing fuselages?  We would love to know.
Title: Re: SLC OVER Polyspan?
Post by: 944_Jim on January 11, 2021, 06:03:45 AM
Gents,
I've never seen SLC. Is this a micro-thin plastic like DocLam? I ask because I am a dope and tissue guy willing to try new things. But in Mississippi, there are no resources for stuff like we use.
Thanks much!
Title: Re: SLC OVER Polyspan?
Post by: Fredvon4 on January 11, 2021, 09:59:17 AM
Jim with exception of Hobby Lobby EVERY thing to Lampasas is mail order

Super Lite Covering was so very thin but strong clear covering heat shrink the Phil Cartier supplied with his foam wing kits and sold by the 100 foot or smaller sample length
2 or so years ago his supplier of SLC crapped out and the all the replacements he found are not quite the same,  and he isn't getting any cuz the min order is way to many miles of film from what I understand

Doculam, FasCal and other heat shrink and glue film with or without backings are available from many sources...I will send you some SLC as a teaser
Title: Re: SLC OVER Polyspan?
Post by: Larry Renger on January 11, 2021, 05:54:56 PM
Also I use the park fLyer weight iron on coverings. They come in just about any color you want. For a large model the weight penalty of standard Monokote or SOLARFILM would not be a problem, still less than a full paint finish.

We have a member in our club who is an executive in a sign/printing shop. They use two weights of laminating film for signs and documents. You could probably beg or buy some from a local shop.