yet another polycrylic question...

I've heard that PC sticks to nitrate dope but not to butyrate. What is your experience? what about the other way around: does either nitrate or butyrate doe stick to PC?

Have you used PC on silkspan over open bays on wings? How did you do it? and how well did it work? Would you do it that way again?

I didn't have any problem with PC over butyrate dope. Stuck fine. I did some experiments with PC over silkspan on open bays. Best seemed to be putting the silkspan over the open bay with dope. Slopping on 2 or 3 coats to insure shrinkage, then put PC over that.

I was able to use just silksapn and PC and the current plane is done entirely without dope: just PC. But it's a pain. The silkspan will skrink some, but not entirely. Took a lot of time with a heat gun while it was wet to get it to shrink acceptably. Still not as tight as I would like, but OK.

I am in the process of refinishing a large stunter. Once I had the paper etc stripped down to bare balsa, I sanded it and flowed on two thin coats of polycrylic (Min Wax blue can), using the foam type brushes. Sanded and applied three coats of butyrate clear(Brodaks), applied silkspan with thinner and now have two coats of Brodaks clear butyrate over that. No problems. I tried this first on a test strip of 3/32 bare balsa to see if it would work. 8 months later the test strip is like day one of the finished test. For what it's worth.

Hi Ty,

Another note. The current plane has 2 coats of Polycrylic followed by silkspan then 1 coat of PC. I had to use a hair dryer to get the silkspan to stretch. Don't know that I would do this again, but it did work mostly. Then one semi-heavy coat of K-36 catalyzed primer and a second coat over a couple of areas that needed it. Now all this was sanded between coats and the final K-36 coat was sanded almost off. But then I had a brilliant idea. Where I had sanded the primer, there were a couple of spots that looked like almost sand-throughs. Just a little questionable. I ended up spraying a thinned coat of PC over the top of everything and sanding in down with some 400 W/D used dry. The entire process only added about 1 oz.

The final surfacing looks really good. I'll next shoot on the urethane color. I'll let you know if it sticks.