• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.

Waterproof and paint foam board; easy method. Also reinforcements.

#1
The video you all posted about water proofing foam board with brown paper and polycrylic was way to messy and cumbersome. There is a much simpler solution; oil based varathane (not water based varathane). Simply wipe on a thin coat with a rag or paper towel, wipe off the excess, and when its dried you have a water proofed foam board that is now easy to paint. You can spray paint all you want without worrying about wrinkles. See the photo attached of my wing section of my Simple Storch. I used paint sticks hot glued to the fuselage sides to reinforce the wing saddle and the skewers for the rubber band hold downs. I also used Popsicle sticks to reinforce the servo mount area for a more solid servo mounting and on the elevator to strengthen the elevator halves. From Lewis Howard
 

Attachments

Ketchup

4s mini mustang
#2
That method is usually called minwaxing. The problem though, is that after doing this hot glue will not stick to the foam. So it has to be done after building or it has to be done carefully. The other method is better for flite test though because of their building methods and kits.
 
#3
You are right. I waited till I finished the air frame and then minwaxed. I'll sand off the paint/minwax off my servo mounting areas before gluing in my servos. Thanks for the information. Lewis
 

FDS

Well-known member
#4
You can also cut through the paper in servo mounting points, then peel it off so they stick direct to the foam. That stops them peeling the paper off in flight.
 
#5
Thanks, but I glued the servo reinforcement mounts on before I min-waxed the plane so there shouldn't be a problem. I will sand the paint off the sticks for better adhesion.
 

Headbang

Well-known member
#6
The video you all posted about water proofing foam board with brown paper and polycrylic was way to messy and cumbersome. There is a much simpler solution; oil based varathane (not water based varathane). Simply wipe on a thin coat with a rag or paper towel, wipe off the excess, and when its dried you have a water proofed foam board that is now easy to paint. You can spray paint all you want without worrying about wrinkles. See the photo attached of my wing section of my Simple Storch. I used paint sticks hot glued to the fuselage sides to reinforce the wing saddle and the skewers for the rubber band hold downs. I also used Popsicle sticks to reinforce the servo mount area for a more solid servo mounting and on the elevator to strengthen the elevator halves. From Lewis Howard
Down side to minwaxing is when it soaks into the paper it makes the paper very easy to de-laminate from the foam. Only really an issue if you crush the foam tho. I use this method with every dtfb plane I build
 
#7
Thought I would add in my method. I build the planes like normal with untreated foam board. Then I put some oil based polyurethane in a cheap harbor freight spray gun and coat the entire plane. Once dry a light scuffing then I use any craft paint and detail it up. It adds very little weight this way and the glue and tape stick as they should to the bare foam. Then all electronics are installed. You can also use a spray can of it if you don't own an air compressor large enough, but a quart of poly and a spray gun is a lot cheaper in the long run.
 
#8
Interesting idea using a spray gun, but I just use a paper towel dipped in polyU and wipe it on after the plane is built then wipe off any excess. It's a lot cheaper and less complicated. I've been flying the simple Storch for the last month and it's holding up really well.