Solarfilm wing covering: my dubious, bodged experiences
My Sophisticated Lady (seen in my avatar) is covered in Solarfilm (probably similar to Ultracote). I received the glider fully built and covered, and the covering was quite wrinkly in places.
After receiving advice from a member of the Ivinghoe Soaring Assoc. I decided to stretch the film, using heat, to remove the wrinkles. The guy told me to use a standard clothes iron at the lowest heat setting, and just hold it above the film until it shrank into position.
I tried this: it did not work. The iron wasn't even hot enough on max setting.
I then considered using a candle - after all, my (failed) barn owl project had an EPP body covered in tape that I shrunk to fit over the hob. So, I lit the candle.
About an hour or two later, the wrinkles had gone fromt he wings and fuse, but I'd added four small holes... and about 10 degrees of warp!
Right, I thought, how can I fix this... aha, I should stretch the bottom of the warped wing to pull it back into shape!
Bad idea!! The trailing edge is now pulled down slightly, flaps-style, because I stretched the bottom of the wing too much.
Then, and only then, did I have a burst of inspiration: read the instructions! I retreived the Lady instructions, which detailed a sensible way to remove the warp. One problem, though: it involved an iron, one of the modellers' irons that I don't actually have.
So, I bodged one together. I took one handkerchief and folded it into a rudimentary iron shape, and placed the clothes iron upon it. Then, I placed the whole lot onto one fully-unfolded hanky and tied it around the iron, so as to keep the folded hanky under the iron.
I found that on a medium teperature setting (not high enough to burn the hanky!) when run over the film, the iron would cause it to go wrinkly until it was removed, whereupon the film would shrink again. I un-warped the wings and added a bit more washout (there has previously been a tendency for a wing to drop at a low-speed mushing stall.)
I hope it will now work better than it did before... the trailing edge is all I'm worried about now.
Morals:
1. Do NOT use a candle to stretch the film.
2. It can be done without expensive specialist tools!