I just finished recovering the right wing of my Paragon glider after a little crash last month. Once done I noticed two things that really bother me. One thing is where the polyhedral break is for thw wing. When I go to cover the outboard panels, I have nothing to tack down the inside of the monokote (side where the polyhedral break is) to except the covering on the inboard panel. I iron it over the other monokote, but then when I go to shrink the wing panel with the heat gun and give heat on or near the joint, it starts to shrivel a bit and nasty bubly looks comes through the transparent monokote as I try to shrink all the wrinkles out of the adjacent covering! The only surface I have to really tack it down to is the ribs @ the polyhedral break, but thats hardly enough area for the monokote to get a good grip. How do you pro glider builders monokote your wings then @ the poly breaks? That nasty bubble effect also seems to happen over the sheated areas of the wing. I try to pull it as tight as I can before I go to heat it, but the wringles just dont wanna go out over the sheeting. The more I heat it, the nastier it looks with the bubles and stuff forming in the monokote.

Maybee my problems are arising from using the transparent stuff but the transparent monokote is so much better for gliders IMHO. I think I am correct in my assumption that I should NOT be ironing over the sheeted areas but just tacking down the edges and heating with the heatgun? Anywyas, just wonderin how you handle the covering @ the poly break. Thanks for any help and I will try to take some pictures tomorrow.

At the top poly-break, I cover the inboard part first, wrapping the coverring around the outboard edge of the break-rib to give the covering a grip. The outer panel is then put on over the inner panel, about a 1/4" overlap. It pays to keep it tight chordwise when doing this.

And a wet rag on the seam will keep it from lifting when heating adjacent areas.

I've taken to insetting a piece of capstrip material (1/16" X 1/4" or so) flush with the top of the rib at the polyhedral break to give a little more surface area to stick to. (do it on both inboard and outboard sides of the rib) I've had a problem with covering lifting from an un-widened rib even if it was stuck down smoothly to start with.

It also might be a good idea to use your iron to shrink the covering in that area rather than a heat gun... it's easier to control where the heat goes with the iron.

One common problem people have with MonoKote is a too-cool iron or heat gun. The temperature of the iron should be just below the melting point of the material. The way I set up my iron is to dial it all the way up. After it's had time to warm up and stabilize, I touch it to a scrap piece. If should be hot enough to immediately put a hole in the material. I then dial it down a bit and wait for it to stabilize. I keep repeating the process until the iron is just cool enough that it doesn't dull the finish with its heat. If the finish dulls, you know the iron's still too hot. This is the proper temperature to get good sealing and shrinkage with an iron.

Many heat guns are also too cool unless you get right down onto the material. Again, with a piece of scrap, you should learn now close you have to get the heat gun to the material before it starts to melt the material. I've seen heat guns that were cool enough that you couldn't get a good shrink even with running the nozzle just off the surface of the material.

With a properly-hot iron and heat gun, getting the material to shrink and stay shrunk is easy and effortless. Of course, the different colors handle a bit differently, with the transparents and chrome needing more heat because they allow the heat right through or reflect it right back.

Where you have an overlap you don't want to come apart, a length of wet, rolled-up paper towel over the joint will prevent it from lifting up, as MinnFlyer mentioned.

(edit) I forgot to add that when the MonoKote ends at a rib, such as at a polyhedral joint, and the rib isn't capstripped, doubling it is a good idea because shrinking one side first will pull the rib and make it hard to get a good, even shrink in the bay immediatly inboard of the poly joint, as mentioned above.

bax