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Author Topic: Fast Finish  (Read 1567 times)

Offline Ken Culbertson

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Fast Finish
« on: January 16, 2019, 12:30:54 PM »
I need to finish a plane from bare balsa to flying by mid Feb.  Covering will be polyspan and power is electric.  I can wait till later for the clear coat and elbow grease.  I want to use lacquer and Rustoleum but I am concerned that I will not get a good bond through the polyspan.  If I use dope I won't have time for it to degas unless I use the same dope for the color. 

I have tested the lacquer on the carbon vale and it appears to bond just fine.  The dope I have is Randolph nontauting which I have been told is basically lacquer but if that is true, why does it bond better than lacquer?

I could also use z-poxy for part of the process but I have never used it before.

So, to sum it up, how do I get a usable finish in a week that won't prevent me from getting a real finish later and , yes I have considered just Monokoting it and refinishing it later.

Ken
 
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Offline Tim Wescott

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Re: Fast Finish
« Reply #1 on: January 16, 2019, 01:51:06 PM »
I wouldn't get close to it with the Rustoleum.  It needs two weeks to get fuel proof, either it won't paint onto lacquer or you can't paint lacquer on top of it (I can't remember which it is -- I think you can go enamel on top of lacquer, and then you're stuck).  I would only go with Rustoleum as a companion to 'coat, and only if I weren't trying for a 20-point finish.

I'd be really tempted to go with whatever I was going to use for a base coat (clear dope or clear dope mixed with my base color) & vinyl stick-on lettering for the one contest.  Or finish the whole thing out but for the rubbing & clear.  Then clean it up and finish it afterward.
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Offline Paul Wood

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Re: Fast Finish
« Reply #2 on: January 16, 2019, 02:10:20 PM »
Ken,
Since you're using electric power, you can use almost anything for your finish. I would seal with the lacquer or MinnWax Polycrylic (water based and quick drying). I would use DupliColor lacquer from an auto parts store. It dries fast and later you can sand it and apply DupliColor filler/primer to hide the grain. Then color with DupliColor lacquer or enamel.

The spray can enamels would work for a quick finish, but would be difficult to apply anything over later for your final finsh.

Paul

Offline Steve Helmick

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Re: Fast Finish
« Reply #3 on: January 16, 2019, 02:11:56 PM »
You've got me a bit confused. The Randolph "dope" can be either Nitrate or Butyrate and still be non-tautening. So, I don't understand why you're using "lacquer".  Since it's electric, it'll be fine without butyrate dope, but then it's not likely you can get colored lacquer except for Krylon or Dupli-Color. Partly, because Nitrate "dope" is pretty much the same thing as furniture lacquer, and I wouldn't expect a significant difference in off-gassing.

And partly, because I'm less trustful of what paint makers label their products, after seeing "clear coat lacquer" at Tractor Supply. They said to apply it over enamel, which means it better not be lacquer! Probably Chinese stuff, but often product labels only tell you who distributes the product and not where it was made or even canned. Doesn't make it bad, but the labeling was very doubtful, and tells me it's probably not a good place to experiment.

So, I'd suggest making the control surfaces removeable, do the dope part, and leave the Rustoleum and clear coat for later.  :P Steve 
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Offline Ken Culbertson

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Re: Fast Finish
« Reply #4 on: January 16, 2019, 02:51:54 PM »
You've got me a bit confused. The Randolph "dope" can be either Nitrate or Butyrate and still be non-tautening. So, I don't understand why you're using "lacquer".  Since it's electric, it'll be fine without butyrate dope, but then it's not likely you can get colored lacquer except for Krylon or Dupli-Color. Partly, because Nitrate "dope" is pretty much the same thing as furniture lacquer, and I wouldn't expect a significant difference in off-gassing.

And partly, because I'm less trustful of what paint makers label their products, after seeing "clear coat lacquer" at Tractor Supply. They said to apply it over enamel, which means it better not be lacquer! Probably Chinese stuff, but often product labels only tell you who distributes the product and not where it was made or even canned. Doesn't make it bad, but the labeling was very doubtful, and tells me it's probably not a good place to experiment.

So, I'd suggest making the control surfaces removeable, do the dope part, and leave the Rustoleum and clear coat for later.  :P Steve
it is Nitrate and the surfaces are removable already (roberts pockets).  I prefer using dope to stick everything on and seal the polyspan but could use something else.   What do I use for color that I don't have to mail order (no time) and will not screw up the dope's degas?  I am pretty much on a path to Monokote now & refinish later.

Ken
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Offline Tim Wescott

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Re: Fast Finish
« Reply #5 on: January 16, 2019, 03:20:01 PM »
it is Nitrate and the surfaces are removable already (roberts pockets).  I prefer using dope to stick everything on and seal the polyspan but could use something else.   What do I use for color that I don't have to mail order (no time) and will not screw up the dope's degas?  I am pretty much on a path to Monokote now & refinish later.

Ken

It's mid-January now.  If you're in the continental US, you can order colored dope from Brodak and it'll be there in a few days without you having to do anything special.  If you're still in bare balsa you won't lose any time.  If you're in the Portland Oregon area you can get Sig dope from Tammy's, albeit only in 4 ounce bottles -- there may be That One Shop close to you that has some.

I would only use nitrate for the sticking part, and then switch to butyrate -- all the colored dope is butyrate anyway.

A good reason to hesitate to Monocoat now & refinish later is that it's really easy to melt Monocoat (or any 'coat) glue into the wood, at which point it'll never come out.  Then you need something that really really covers well (= heavy).
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The problem with electric is that once you get the smoke generator and sound system installed, the plane is too heavy.

Offline Ken Culbertson

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Re: Fast Finish
« Reply #6 on: January 16, 2019, 03:50:53 PM »
It's mid-January now.  If you're in the continental US, you can order colored dope from Brodak and it'll be there in a few days without you having to do anything special.  If you're still in bare balsa you won't lose any time.  If you're in the Portland Oregon area you can get Sig dope from Tammy's, albeit only in 4 ounce bottles -- there may be That One Shop close to you that has some.

I would only use nitrate for the sticking part, and then switch to butyrate -- all the colored dope is butyrate anyway.

A good reason to hesitate to Monocoat now & refinish later is that it's really easy to melt Monocoat (or any 'coat) glue into the wood, at which point it'll never come out.  Then you need something that really really covers well (= heavy).
Good points. I am going to split the baby.  Carbon and about 2 coats clear proper sanding no sealer.  One coat clear light 600 grit sanding.  Monokote should stick but not deep.  (I normally don't put anything other than balsarite on it if it is to stay monokote.).  Should come off easily with a heat gun and a little tugging.  Then sand, filler, recover with polyspan etc..  Maybe I will just do the wings or maybe I will listen to you and just do it right except for the final clear coats.

Ken
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Offline john e. holliday

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Re: Fast Finish
« Reply #7 on: January 17, 2019, 11:27:03 AM »
Best bet and even though you want it done by mid February do your finish that will give best results.   If you have another plane use it for what ever event you are shooting for.  I used to do this for VSC each year and wind up with plane that didn't get flown until I got to Tuscon.   Needless to say I had some bad results.   That is why the last few years I was able to make VSC I had planes I had some confidence in how they would fly.   Tuscon is a different atmosphere than Kansas City.


By the way why the rush???? ???
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Offline Ken Culbertson

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Re: Fast Finish
« Reply #8 on: February 05, 2019, 01:41:01 PM »
As with most projects, making a timeline is just a way to waste a few minutes you could otherwise use building.  The Feb. deadline is just not going to happen so I will take the advice given here and fly something else. That takes MonoKote off of the table so I just need to know if a Polyspan covering with a Nitrate (Randolph non-tauting from Aircraft Spruce) base and Rustoleum 2x (From the Walmart paint section)  for the color is still comparable.  I read everything I could find on search and It appears it will be just fine but most of the posts were 5-10 years old and formulas change so ... any recent advice?

Ken
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Offline Dan McEntee

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Re: Fast Finish
« Reply #9 on: February 05, 2019, 08:30:41 PM »
    If you are going with polyspan, even though it will heat shrink some, I would still put at least a couple of coats of tautening dope on to fill and finish up with non-tautening. All nitrate might be OK if going over it with Rustoleum. I just don't know if those two are compatible at all in any form.
   I still contend that there is no such thing as a "fast finish."  Guys have been trying to find it for as long as there has been silk span and dope. The quickest finish I have found has been Allen Brickhaus' finish methos that involves iron on covering, spackle compound, finish cure epoxy and rustoleum or x-o-rust paint. The short version is a layer of watered down spackling compound, sand when dry, and then another coat and sanding. Then a layer of thinned finish cured epoxy, scraped and blotted off, then sanded. Apply a little more to hit light spots. Then primer and paint. Wings are covered with iron on covering first, then wrapped in foil for protection through the other process. The epoxy coats overlap over the iron on coverings. The iron on coverings is failr fast but still a lot of work to do well. He covered the whole process in detail ina couple of his construction articles, one being his semi scale Beguine P-51. It is worth checking out. I have done a few this way with decent results and I didn't do it exactly correct either.
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Offline Dave Hull

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Re: Fast Finish
« Reply #10 on: February 05, 2019, 10:14:33 PM »
Using Rustoleum as a topcoat over polyspan or silkspan will give a more "rubbery" finish than straight dope. I have two Fancy Pantses right here: one with SIG dope, and one with Rustoleum. If you tap on the wing covering in the same place on each, the SIG model goes "tink, tink, tink."  The Rustoleum model goes "tunk, tunk, tunk." Less shrinkage, not as taut. I wouldn't worry about it unless you are building an I-beam wing, or something lightweighted to the point that you need the torsional stiffness from the doped covering.

On the other hand, the fillets on the Rustoleum model have not pulled up, whereas the SIG model has superlight (air-filled) fillets.

Dave

Online Dennis Toth

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Re: Fast Finish
« Reply #11 on: March 03, 2019, 01:07:22 PM »
Ken,
Since it is electric the lightest finish is good old Sig or Brodak butyrate dope (look on YouTube for WindyU finishing videos). The only reason we use the auto finish is to keep the finish fuel proof. B dope will rub out to a very high luster and stay as long as you don't spatter fuel on it. The Rustoleum is usually used with MonoKote on the flying surfaces for those sensitive dope fumes, if you use it on the whole ship it is very heavy. You could also use rattle can Krylon or Dupli-Color, they are dope like and should be similar in weight to dope but you have to watch the humidity. If you are in a high humidity area you can use some retarder in the dope to keep the haze off but you will need use a stand alone spray system (could be as simple as the Preval sprayers, at home depot. lowes, etc. about $4.50 per unit).

Best,   DennisT


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