Hi Folks,
I had an interesting experience the other night with the Mono Kote covering on the plane (ARF) I'm building. First off, I am brand new to the hobby (6 months) I have a Sig Kadet trainer that I'm learning on and bought a couple of ARF's to build. Got bit by this RC Bug pretty hard. The plane I'm working on, I don't remember the brand (Import), but the name of it is 'Fascination'. It's a 55!QUOT! wing span, mid wing, very colorful aerobatic style plane. Now you know why I have the Kadet. I bought this and a CAP 232 before I learned the flying characteristics of the different style planes.
The problem I ran into was I had a couple of small (what seemed like) air bubbles under the Mono Kote on the fuse by the landing gear on the left side. I broke out the heat gun and started heating the area on low heat while smoothing it out with one of those fleece type gloves. I could see the covering getting softer but it still would not stick back down to the wood even with smoothing it with the glove. When I started this project, I did this heating in a circular motion over the whole plane to get the covering good and stuck with out any air bubbles (from the instructions). This time the bubbles traveled down the length of the fuse. When I pointed the heat gun toward the bubble in a circular motion it started to suck the coating down to the wood and smooth out any bubbles until I got to the edge by the opening for the wing. The covering just came loose from the wood and shrunk up to half it's original size. No way was it going back to size so I kept lightly heating until I removed affected the front lower section. I picked up a roll to recover it but I have no idea what I did to shrink it up. I don't want to have any repeats of what happened.
Any thoughts from any of you with covering experience on what caused the bubbles to travel or the shrinking? I have zero covering experience at all but I'm learning all the time. Any suggestions on what to do or not to do will be greatly appreciated.
Thanks,
Peter

Peter,

Take a very small pin and poke a hole in the bubble, then heat away. The most common reason why a bubble travels is because there is no where for the hot air to escape. Also It is not uncommon the have to go over the edges of the covering with an iron to make sure that it is glued fairly well before using the heat gun.

I do it the other way around. Take your heat gun and heat the monocoat up, since hot air rises, it'll mound up in 1 spot. Go ahead and poke that spot and you'll see the bubble pop and it'll turn out nice and smooth.

byris is more correct. I just didn't explain it as well sorry

Another thing that helps eliminate it from happening is to use a woodpecker on any sheeted areas before covering... That gives the air someplace to escape without poking holes in your convering...

Poke the bubble trick is good. Its my opinion that Monokote bubbles easier cause it requires more heat than some other brands, to shrink. Any air underneath the covering gets heated to a higher temp before the shrinking begins. Another thing to do is make sure that the surface is SMOOTH before covering, and NO dust either. Those two things, along with the proper temp, and technique, and the right covering material make all the difference.

Jim C

after using about 8 brands of covering over the years; monokote is somwhere in the middle heat wise. the reason it bubbles due to trapped air is the type adhesive used. otherbrands , incl ultracote do not form as much gas &have less problems.