Patriot

I ran across a thread where a gent who was finishing a cub was adding baby powder to the nitrate dope to fill in the Koverall weave to make it smooth with no texture. This technique works very well, but he stated that after brushing on the dope/powder mix, he could visibly see alot of brush strokes. Everyone that responded said to sand it until there were no strokes visible, as he made a mistake and added too much powder, or too thick a coat, etc.
So, as a reminder to those who use Koverall and want to fill the weave with baby powder, the brush stroke appearance is very normal. As it soaks throught the fabric, it will collect more heavily in some areas than others. The real key is the sanding. Just sand it with 320-400 grit until it feels nice and smooth to the touch, with no rughness.
Believe it or not, when you prime the surface, the primer will usually fill in any left over minute roughness or imperfections prior to painting. Plus, the primer can also be sanded gently to assist in smoothing the surface even further. That's it.
I just got done covering an 80" wing with a powder/dope finish, and had a whole wing covered in brush strokes. After priming, Whalla!!! No more brush strokes.

Patriot

1/4 flyboy

My Feedback: (1)

Patriot

I will be at that step in a couple of days . I heard to mix 1/3 talc 1/3 nitrate 1/3 thinner sound about right? I have used sig products alot but first time I will try this process.

Patriot

Yep, that's about right, and if you get brush stroke pattern after it dries, that's ok, just sand w/400 grit til' smooth to the touch. If you keep sanding to get rid of the lines, you'll go way too far and end up with sanded fabric fuzzies.
Just put my first coat of primer on, using a real dusting method so it goes on very lightly and covers slowly and evenly. Makes for very smooth sanding. And almost all imperfections are filled. Second light primer coat should take care of it all.
I plan on using Rustoleum, and a clear pearl coat two part finish for extra fuel proofing. Should look interesting, but that is still aways off. Still have to finish covering the fuse. I love this stuff, it is sooooo strong compared to monokote.

Patriot

yankee samurai

My Feedback: (175)

I have been using talcum powder and dope for longer than I can remember. I still use it today. If you have access to a sprayer it can be sprayed on with excellent results. No brush strokes to worry about. Just thin it enough to where it will go through the paint strainer, and go for it. You end up with an even layer that sands off and fills beautifully.

Patriot

GREAT IDEA!!!

I always assumed it seemed way too thick to be using in a sprayer. When I mix it, it always comes out pretty thick, similar to unthinned dope after the powder is mixed in.
You have no trouble with spotting? Or Clumping?
I am planning on getting a compressor in my garage, and will have to try that next time.

Patriot

Mike Buckley

Just a tip, if you are worried about weight at all use microballons instead of the talc!

cheers, Mike

Patriot

Never thought of that. I may be wrong, but talc is about as cheap as you can get. I know micro-baloons are not THAT expensive, but talc has always worked best for me. I even use it in epoxy for filling.

Patriot

Mike Buckley

Good point about the price, I just used them to glass and fill the weave on my GWS Mustang. In that application it was worth the extra money to avoid ANY extra weight!

Patriot

I'll have to try mocro balloons sometime. Getting ready to start covering the ufse. Wing is covered, ready for paint.
Engine also showed up testurday, ,Enya 155. This thing is really coming together.

Patriot

kdheath

FWIW, the lightest available filler material may be zinc stearate. Can be obtained from chemical suppy houses or Tom Dixon on the web.