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Author Topic: Polyspan fuzzies  (Read 1785 times)

Offline Mike Morrow

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Polyspan fuzzies
« on: March 08, 2020, 01:32:36 PM »
I'm using polyspan on the wings of an RSM Ringmaster. I've used it on several planes now and like it because it's pretty strong stuff. But, no matter what I do I always end up with some of the fiber raising up and popping through the final color coat on the open bays.  HB~> HB~> HB~> I put on 7 or 8 coats of dope, very lightly sanding with 400 grit after I got several coats on. Some showed through the primer and I thought I got all of them. I know I have the correct side out. What is the trick to making this stuff look as smooth as silkspan? Thanks,
Mike

Offline Dan McEntee

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Re: Polyspan fuzzies
« Reply #1 on: March 08, 2020, 02:11:18 PM »
  Hi Mike;
    I don't have too much experience with polyspan and like what I see so far. This has been discussed at length several times on the forum, so you might want to search this out with a couple different key words. Going from memory, if you are sure you have the correct side down, make sure you have enough dope on the frame when applying the covering and sanded well before covering. When doping down the covering, try making the brushing dope a bit thicker, but no so thick that you won't soak up the build up from the frame. Think of coating all the fibers in the material from both sides. Don't sand between the first three coats or so when applying the filler coats, and when you do start sanding, maybe go to a finer paper than what you have been using, and just sand it a bit more. using a block will help keep the surface flat. If when you are doing your final sanding, and you get some fuzzies, I have always wondered what doping down a piece of light silk span on the spot would help, kinda like patching a hole. Tear a round patch, not cut with scissors, and dope in place. The rough edge helps the patch to blend in. Block sand this down and see if you can feather the edges in. The paper will give you something to fill and sand off and hopefully trap the fuzzies. I hope to do more covering in the near future and have a Twister covered with Polyspan that I need to finish up and hope to try some of these ideas. Zinc sterate (spelling?) is used as a filler for dope when doing buildups, and I wonder if a slightly thicker solution of that in clear dope applied to fuzzies would help fill them and make them easy to deal with. But in short, a little more dope and a bit finer paper with more sanding with a block may get you where you want to be.
   Good luck and have fun,
     Dan McEntee
AMA 28784
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AMA 480405 (American Motorcyclist Association)

Offline Mike Morrow

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Re: Polyspan fuzzies
« Reply #2 on: March 08, 2020, 02:43:13 PM »
Thanks Dan. I did the search and read what others did. That's why I used 7 or 8 coats of dope figuring it would seal it all down this time. I'll try 600 grit next time and see how that works.

Mike

Offline Howard Rush

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Re: Polyspan fuzzies
« Reply #3 on: March 08, 2020, 05:15:58 PM »
Thanks Dan. I did the search and read what others did. That's why I used 7 or 8 coats of dope figuring it would seal it all down this time. I'll try 600 grit next time and see how that works.

Your search should have told you what does work.  Sounds like you want to creep up on it.
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Making combat and stunt great again

Offline louie klein

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Re: Polyspan fuzzies
« Reply #4 on: March 08, 2020, 06:52:14 PM »
Steel wool does the job.----Louie

Offline wwwarbird

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Re: Polyspan fuzzies
« Reply #5 on: March 08, 2020, 07:40:02 PM »
 
 As long as the correct side is down I've never had a problem with the fuzzies. Once attached and shrunk I usually only give it 5 or 6 heavy coats of 50/50 clear, dry sanding very judiciously and lightly with 800 in between coats after the third coat, and then go right to color. That's how this one was done...
Narrowly averting disaster since 1964! 

Wayne Willey
Albert Lea, MN U.S.A. IC C/L Aircraft Modeler, Ex AMA member

Offline Mike Morrow

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Re: Polyspan fuzzies
« Reply #6 on: March 09, 2020, 04:14:38 AM »
Thank you for all your responses. From what you guys are saying I think maybe I'm being a little heavy handed when I sand. We'll see if I get right next time.

Mike

Offline Joe Ed Pederson

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Re: Polyspan fuzzies
« Reply #7 on: March 09, 2020, 06:25:56 AM »
I finished my first wing using polyspan/Brodak dope last fall.

I knew not to sand at all until at least 3 coats of clear, but I sanded too much in some places in removing Brodak White Primer (white dope with a lot of talcum or something similar in it) and got some fuzzies.  I used Brodak rejuvenator (dope) on the fuzzies and that seemed to knock them down better than just clear dope.

I got the idea of using rejuvenator on the fuzzies from Windy Urtnowski's videos on using Brodak dope.  He recommends using rejuvenator if you sand through silkspan on the ribs and need to lay down little strips of silkspan to cover where he sanded too much.  He explained that rejuvenator has a lot of plasticizer in it that helps with the patches. 

What I didn't know until I finished the wing was not to use the white primer in the open bay areas.   On one of his videos Sparky says it's a waste of time and effort using primer/dope with talcum in the open bays and also adds needless weight.   Boy did I cause myself a LOT of needless hours sanding.  Ya live and learn.

Joe Ed Pederson
Cuba, MO

Offline Ken Culbertson

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Re: Polyspan fuzzies
« Reply #8 on: March 09, 2020, 06:36:03 AM »
. Don't sand between the first three coats or so when applying the filler coats, and when you do start sanding, maybe go to a finer paper than what you have been using
Ditto's to Dan ...I don't have any problems using 600.  You might consider brushing on the early coats and do not sand the ribs until you are sure it is filled.  Another thing I have used is to gradually tighten it over the bays using non tauting dope and light heat from a monokote gun while it is still drying.  This lifts it up slightly around the ribs and sheeted areas.  Too hot and it makes pin holes so be careful.  I also don't use filler at all any more, just primer.   If you sand through just burn the plane and start over. LL~

Ken
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USAF 1968-1974 TAC

Offline Mike Morrow

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Re: Polyspan fuzzies
« Reply #9 on: March 09, 2020, 07:29:54 AM »
I'll probably crash it anyway. Who'll know then.

Mike

Offline Shorts,David

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Re: Polyspan fuzzies
« Reply #10 on: March 09, 2020, 10:19:24 AM »
Hi Mike, My first polyspan project is in primer right now. I got fuzzies on three of the four wing panels. That is to say, the one panel I put down before I was paying attention has zero fuzzies. The three I put down after I was paying attention, apparently I got wrong. They seemed smoother on one side, but maybe that's not the trick. Maybe you just have to pay attention to which side the little sticker was on. Mine came with a little sticker showing which side to put up.
But now I'm thinking I might order some of that rejuvinator. Yes, I watched the Windy videos too. I could use it on the fuzzies I got around the edges, but I used some CA to smooth most of the edges down.
Verdict is definitely still out on polyspan for me.
David

Offline Dan McEntee

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Re: Polyspan fuzzies
« Reply #11 on: March 09, 2020, 07:35:11 PM »
Hi Mike, My first polyspan project is in primer right now. I got fuzzies on three of the four wing panels. That is to say, the one panel I put down before I was paying attention has zero fuzzies. The three I put down after I was paying attention, apparently I got wrong. They seemed smoother on one side, but maybe that's not the trick. Maybe you just have to pay attention to which side the little sticker was on. Mine came with a little sticker showing which side to put up.
But now I'm thinking I might order some of that rejuvinator. Yes, I watched the Windy videos too. I could use it on the fuzzies I got around the edges, but I used some CA to smooth most of the edges down.
Verdict is definitely still out on polyspan for me.
David

   Hi David;
    What have you ever done in your life that takes skill and done it correctly the very first time you tried it?  You haven't finished this wing yet but you already know some things to do differently next time. That's called learning. You may surprise yourself how well this one will still turn out, and then how much better the second one will. Just pay attention to the little details and the big ones will take care of themselves sometimes.  Good luck and keep trying!
   Type at you later,
    Dan McEntee
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AMA 480405 (American Motorcyclist Association)

Offline Joe Ed Pederson

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Re: Polyspan fuzzies
« Reply #12 on: March 11, 2020, 01:45:49 PM »
I have a fool proof method. After applying the polyspan I give it one coat of Coverite Coverlite park flyer film.


Motorman 8)

Motorman,

In your experience, how well does Coverlite over polyspan prevent exhaust oil from getting under the Coverlite and polyspan?

I'm inclined to fiberglassed/epoxy paint fuselages and polyspan and dope on wings and tail because every monokote/plastic covered model given me has had exhaust oil soakage/damage.  Right now I'm stripping the monokote off a wing that is oil soaked along the last 1/3 of the trailing edge/flap and the rear of the wingtip on the outboard wing.  (I know how to get the oil out.)

I don't desecrate my coffee with creamer or sugar.   I don't want my balsa desecrated with exhaust oil.  That's the bottom line for me.

Joe Ed Pederson
Cuba, MO


Offline Mike Griffin

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Re: Polyspan fuzzies
« Reply #13 on: April 04, 2020, 07:49:42 PM »
Mike, I do not know if this will help or not but I once put the polyspan on with the Wrong side up and got a bad case of the fuzzies.  I put several coats of dope on it then wet sanded it with 1000 grit sandpaper and it completely got rid of it.   I never had a problem when  put the correct side up.

Mike

Offline Larry Renger

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Re: Polyspan fuzzies
« Reply #14 on: April 05, 2020, 05:58:09 AM »
My Ringmaster with Coverlite over Polyspan never had any oil problems.
Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Offline FLOYD CARTER

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Re: Polyspan fuzzies
« Reply #15 on: April 05, 2020, 04:01:22 PM »
My Polyspan always came on a cardboard roll.  When cutting pieces, it stayed slightly curved.  I got used to applying the curved side up because that was the smooth side. However, the last roll actually had the "fuzzy" side out on the roll.  My habit of using the curved side up failed!  Fortunately, I caught the problem after just one panel was applied.  Now, I very carefully check each piece, although the difference in "smoothness" is slight.
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Offline Shorts,David

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Re: Polyspan fuzzies
« Reply #16 on: April 06, 2020, 05:13:31 PM »
So, I've done my first polyspan paint job now. I had great trouble around the edges with them lifting a bit and wingtips were impossible for me. I also got a certain degree of fuzzies regardless of which side I put down, but one side was definitely better than the other. Also, i barely bump the polyspan and get a hole. Well, two holes appeared on the polyspan and I don't even recall bumping either of them.

So, why not use silk? Real silk. I ask because my one model done in silk (wet method) went together like a dream (compared with polyspan). But, there has to be a reason very few (Charles swears by it) use silk. I do have a few more rolls of polyspan, but I'm about ready to start my PA plane and thinking about placing another silk order. I love ultracote too, but not this time.

I don't like the idea of using two materials, maybe silk for wingtips and polyspan for the rest, but perhaps that is a good solution.

David

Offline Larry Renger

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Re: Polyspan fuzzies
« Reply #17 on: April 06, 2020, 10:14:53 PM »
Lightly applied, wet sanded 2000 grit paper will kill the fuzzies and not cut the paper. End of problem.
Think S.M.A.L.L. y'all and, it's all good, CL, FF and RC!

DesignMan
 BTW, Dracula Sucks!  A closed mouth gathers no feet!

Offline Ken Culbertson

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Re: Polyspan fuzzies
« Reply #18 on: April 07, 2020, 12:11:29 PM »
Lightly applied, wet sanded 2000 grit paper will kill the fuzzies and not cut the paper. End of problem.
I use 1000 with the same results. Another trick I use is to lightly reheat the bay areas after a coat of dope while it is still wet.  All but eliminates the capstrips pulling the covernig down.

Personally I like polyspan after I learned how and where to use it.

Ken
AMA 15382
If it is not broke you are not trying hard enough.
USAF 1968-1974 TAC

Offline Shorts,David

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Re: Polyspan fuzzies
« Reply #19 on: April 07, 2020, 02:46:19 PM »
Does everyone put their polyspan over solid areas, or only Bay areas?
Thanks

Offline Howard Rush

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Re: Polyspan fuzzies
« Reply #20 on: April 07, 2020, 03:11:04 PM »
I put Polyspan on the whole wing. I use black stuff on the rest of the plane.
The Jive Combat Team
Making combat and stunt great again

Offline bob whitney

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Re: Polyspan fuzzies
« Reply #21 on: April 07, 2020, 05:35:37 PM »
sparky has a video  using polyspan on a wing and using a Heat gun to do the tips.got my first diecent tip after watching it
rad racer

Offline Shorts,David

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Re: Polyspan fuzzies
« Reply #22 on: April 08, 2020, 10:56:37 AM »
I'll have to check that out. I probably watched it years ago before ever touching the stuff.


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