As I mentioned before, I am just starting the covering process on my SS7 and I started with the elevator because it is a fairly simple, small, flat item. Now I already have a problem!

I got the fabric glued on all the edges just fine, on both upper and lower surfaces. Then I did the first heat shrink at 250 and find that all the wood ribs that are not up against a metal tube (every alternate one) have buckled a small amount and I have not even done any heating above 250 degrees. The ribs that are against a metal tube have remained straight. The manual did not call for any rib stiffeners on these unsupported ribs, like it does for the rudder and stabilizer. What did I do wrong and what should I do now?

I could just leave alone and not do any more heat shrink above 250; probably the tapes that go over each rib will mostly cover up the snakey ribs underneath. I just bugs me because I know it will show somewhat, and I worry because I was not able to shrink to the recommended 350 degrees.

Help,
Jim