I have been using a product from the local fabric store called Mod Podge.  I think I use the gloss.  Use a foam brush to put on the area that you will put the Poly-Span on.  I brush it on and let it dry as it is heat activated.  If surface is to rough you may have to do a light sanding.  But last couple of planes I did not sand as the heat seemed to level every thing out.  What kind of finish do yo plan on doing over the Poly-Span?  If going with a iron on mylar covering do not seal the open bays of the Poly-Span.  Other wise finish as normal.

But last couple of planes I did not sand as the heat seemed to level every thing out.  What kind of finish do yo plan on doing over the Poly-Span? 

Thanks, I'm using urethane color and clear. 

James

Thanks, I'm using urethane color and clear. 

James

James,

You're using quality finishing paints, a good thing. Keep in mind, Polyspan tears so easy. Why not bridge over to cloth and use silk? You can't tear silk.

Also, if you really want to kick it up a notch, you can apply silk dry with CA as I have on many models. Fast, quick and easy once you get the hang of it. Many say Polyspan and silk span fills with less coats, but I find silk fills with less coats and just about "0" pinholes. The mix depends on the number of coats needed to fill weave. We only have control of our own mix.

I'm just about ready to silk my TEXACO 13. I'm currently prepping the wood. I'll use Deft Wood Lacquer to prepare the wood, couple of coats, then I'll use CA to apply the silk dry and board tight. This technique needs to be explained, however, I've mentioned this in many of my Builds.

I will use clear dope over all open bays, but I'll use Deft on all wood surfaces. I speed dry these coats with a heat gun.

I've also used Minwax because it has less of an odor, but only for layered coats.

A high build primer after this, but most of the primer gets sanded away.

I can't tell you what to do, but this is the process I've used on many models. Photos, texts and Builds are here and there.

Good luck.

I did a search but wasn't finding what I was looking for.  What's a good option for applying Polyspan over open bays without using dope?

Thanks,

James

I have worked with Polyspan and done OK.  It uses about the same amount of dope as silk, silkspan, or tissue. 

I found Polyspan to be rather inflexible and very bad for small compound curves.

The photo is my original Clown racer being retrofitted from a cheap iron-on covering to Polyspan.  The weights allowed me to do an OK job on the wingtips.  Cutting the tip covering into narrow strips avoids the wrinkles that happen without the cuts.

   As usual, as I am sure everyone knows at this point - ignore this nonsense. The hallmark characteristic of Polyspan over Silkspan is toughness - once it is in place and sealed up, it's very durable.  What it has over silk and silkspan is that it *fills very easily*, meaning *light*.  Silk is a decent material, but not tremendously stronger once it is applied, and much more difficult to deal with.

   Bear in mind, Charles does not build flying model airplanes, he builds shiny lumps that can weigh anything, he could mold them from concrete for all the difference it makes. One of his hallmark pointless and intelligence-insulting arguments on SSW was over what constituted "polyspan", so of course, now, any time it comes up, he has to chime in and badmouth it.

     Brett

Brett,

I Post the weight of my models. I have none that went over 55 ounces. At least I Post photos of my work.

Certainly the TEXACO 13 will be a bit heavier, scale always is, but you deal with it. Sometimes it can be an advantage for a more realistic flight. BTW. You never have a kind word to say about me? Or my work?

Finally, we're seeing "two part auto clear" being used more often and I noticed "Krylon" is being mentioned more often also.

As far as "colored dope," well, how I feel about that goes back many years. I knew, eventually, colored dope would be fazed out in place of auto base coat/clear coat.

As far as filling the weave of "any" material, it depends on the mix. Everyone should know this. I'll be silking the TEXACO 13 soon, I'll keep track of the coats before I apply primer.

Silk applied dry using CA is the next thing that will catch on, slowly for sure.

              While it's been noted that Polyspan doesn't conform well over compound curves, the Mod Podge method allows it to do so. You can apply it in the same fashion as Monokote stretching it as you bring it around the tip. The Mod Podge really keeps it in place. On the downside it gets on the iron which isn't easy to remove. I had to really heat it and use Prep Sol on a rag to remove it. I now have a separate iron for this purpose.

Thanks.  Can I fill the "weave" in the covering with Polycrylic?  Will be using urethane color and clear.

James

I've never used anything but dope for that so I cannot advise you there. I would imagine it would be heavy.

Charles,
I'm curious and experiment.
As much as you dislike dope, why are you using it over Deft?

I've used Deft exactly as one would use nitrate right up until using colored butyrate on final top coat with no ill effects to the covering. I would think you could stay away from dope entirely and go from Deft to your favorite paint.

What does the dope do for you that Deft may not? I do recognize I don't build keepers nor large ships...otherwise I wouldn't have room for new planes, so longevity may be my unseen answer.

I ask because I'm thinking of trying Deft under Rust-Oleum with polyurethane as the fuel proofer.

TIA

"Dislike?" It's 2022, there are better products than "color" dope and many guys are gravitating towards them, like the two part auto systems, base coat/clear cote. It's the future.

I don't use "clear dope" over Deft. From Deft I go to primer. I use clear dope over the "open bays" only.

Many models have no open bays.

I don't recommend Rust-Oleum, Krylon "satin or flat" is a much better product. You need the 2 part auto clear to fuel proof. A good thing.

CB

     He doesn't put dope over deft, he puts Deft over dope. See here:  https://stunthanger.com/smf/scale-models/texaco-13-semi-scale-build!!-real-slow-build/
   He probably gets away with that because they are both lacquer products and there really is no need or good reason to use both. He likes to talk out of both sides of his mouth a lot, if you read and follow his "posts." He likes it one day when it serves his purpose and then says ne never uses dope any more when it serves his purpose , but then crosses himself up with statements like the one above. None of it makes sense or needs to because he never puts his stuff to the ultimate test, which is flying and the stress and rigors of flying the pattern.  The last thing you should ever use to hold down a covering material, what ever it is, is C/A glue!
  Type at you later,
  Dan McEntee

Dan,

Thank you for promoting the TEXACO 13 build! It's appreciated.

Yes, I apply Deft "over" dope. Even Minwax over dope. And dope over dope. Just clear dope though, gotta make this point.

      Well, don't get a bigger head than what you already have! I just look in on your builds like people slow down to look at a car or a train wreck!! You have done some seriously weird stuff and have built some fatal flaws into just about everything you've done. Maybe it's a good thing that you never fly your "creations". I predict that you'll never finish the airplane that is technically called a Travel Air Mystery Ship! And in the rare event that you do, actually attaining successful flight will be another thing! Even though you claim to have "been at this for a long, long time" elsewhere in another thread you can't make a major decision with out begging for some help because you have no experience, regardless of what you claim otherwise. So again, you come into a thread where the original poster asks a specific question, gets some good feedback and suggestions, and you barge in and ruin it with your baseless methods that have never been proven. I think you have been using the Deft for some other purpose!
  Type at you later,
   Dan McEntee

Dan,

You know I appreciate feedback. If I have "flaws" in my construction methods you should point them out instead of the flaws in my personality. Poor or incorrect construction issues should be mentioned immediately in fact. It would be appreciated. Too late now for changes, the model is 100% framed.

BTW. You should put photos of your models up. It would give you more credibility.

Thank you again for promoting the TEXACO 13 build. Thank you for following that Build also.

FYI. The TEXACO 13 out performed the others and won more events. The "Mystery Ship" has been done too many times. I did one back in my R/C days. Remember, I had two kits. Built one and sent the other kit to Australia. Two boxes. Fiberglass fuselage cut in half. One half in one box and the other half in the other.

One box went to Brazil unfortunately, but the USPS straightened it out.

That was a tough three weeks.

Charles

     He doesn't put dope over deft, he puts Deft over dope. See here:  https://stunthanger.com/smf/scale-models/texaco-13-semi-scale-build!!-real-slow-build/
   He probably gets away with that because they are both lacquer products and there really is no need or good reason to use both. He likes to talk out of both sides of his mouth a lot, if you read and follow his "posts." He likes it one day when it serves his purpose and then says ne never uses dope any more when it serves his purpose , but then crosses himself up with statements like the one above. None of it makes sense or needs to because he never puts his stuff to the ultimate test, which is flying and the stress and rigors of flying the pattern.  The last thing you should ever use to hold down a covering material, what ever it is, is C/A glue!
  Type at you later,
  Dan McEntee

Hi Dan!
What is "deft"? I've never heard about this stuff...

Thanks!
Claudio.

    Deft is a clear, plain lacquer, usually found at most hardware stores. It comes in liquid form in a can and in a spray can. It's just a general use clear lacquer. I have heard of guys using it in place of dope of free flight rubber model and gliders. Sometimes it's hard to find depending on the local and state EPA hounds. In my work, when laying out scribed lines on a concrete floor for installing printing presses, we would put down a quick coat to seal the line and help it show up better. Sometimes we would spray down some stencil ink first, then lay out and scribe the line, and then seal both with a coat of lacquer. Wood workers use it as a simple finish also. It dries very quick and can be sanded out for more coats pretty quickly. Not much different than clear finger nail polish I would bet!
  Type at you later,
   Dan McEntee

  Most furniture lacquers also have a lot larger solid content than typical dope, so they fill better. It's not even remotely fuel resistant, but it would not be a bad choice for filling weave on electric airplanes - or display models.

    Brett

I use Deft for sealing the wood, and adhering the tissue, or DocSpan. Then it is used to seal the covering I used.  I use it just as one would use NITRATE dope.

I then top/color coat with butyrate for fuel-proofing. However, I am close to the end of my stash of original Pactra AeroGloss. That low stash count is what lead me to ask Charles why he didn't bypass butyrate after using dope. I got alternatives, but never got a direct answer to the question.

My next model will be covered using Deft, and then topcoated with SLC provided by FredV4, and as described by Mr.Renger in other threads.

Deft in quart PN 010 cost me $12 about two or three years ago, and I'm running low on that too. I can post a picture if it helps anyone.

PS I fly smaller models, and never plan/build to keep them until I die. Otherwise I'd never have room for another. That may be why it works for me...I don't keep them until the covering shrinks and tears just sitting on a wall.