I should also mention that I'd put in a "bleeder layer" of paper towels directly above the bubble, then a layer of builder's plastic (to keep the topsoil bag from sticking), and then weighted the topsoil bag with 70 pounds of gasoline cans. I really thought that would work, but only one of three was anywhere near "close enough", and the other two have now been cut out and patched, with excellent results. It's amazing how quickly little repairs like that go, when you're not talking about doing something as huge as an entire wing or something. Vacuum bagging would be the intelligent way to do this, obviously.
A post mortem of the patches revealed no two part urethane foam, just a fracture of the foam about an eighth of an inch deep, so the glass had a good connection to the foam, but the foam itself broke. The only cure I can think of for that would be to use 4 pound Lastofoam instead of 2 pound urethane, but that's a high price to pay when you're talking about the whole airplane. I am using Lastofoam to build my baggage area behind the seats though. Mark Langford, Huntsville, Alabama see KR2S project N56ML at http://home.hiwaay.net/~langford email to N56ML "at" hiwaay.net
