Thorp Air Command - T18.net

Time for a new windshield for 99KK. Last one crazed after about 6 years (I am guessing due to off-gassing of the vinyl dash top). This time I am making my own. I made an oversize mold from old w/s
& will make an oven from insulating board. - It doesn't look too difficult as it it is a flat wrap (what this means is I will probably only have to throw away my first attempt & get it on the second). Any tips or hints on the forming process would greatly be appreciated.

Forming temperature is critical. Too cold and it will craze, too hot and you get mark-off from the mold. Use flannel to cover the mold. Some people grease the flannel. Probably the most important is the type of Plexiglas you use. I don't recommend Lexan; it is gummy and will eventually cloud up. The local plastic shop probably has a wealth of info on optics and forming temps. Let us know how it goes.

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Bob Highley
N711SH
SN 835
KLAL

Check the NL's . Pretty sure there were a couple of articles on how to bend the clear stuff . One even mentioned the use of a local pizza oven ?

Thanks for the info. I will take some pics & keep everyone posted on the results.

Doug I have had a lexan windshield for 15 years, 7 for the present one, no heating just cut it to size and bend it around. Does scratch a little easier then plexi but it works for me an you can get it tinted and there is some available that is scratch resistant . Also better impact resistant.

Lance 38DT

Lance is right - Lexan (polycarbonate) is tougher, more impact resistant & less prone to cracking, and you can cold bend it. You can even bend it with a sheet metal brake if you need a sharp bend. Some of the newer versions do have a much better scratch resistant surface than plain Lexan. I don't think that they are still as good in that regard as Plexiglas (acrylic), but I'm not up on the latest & greatest. One thing you have to be careful of with Lexan is exposing it to fuel or even concentrated fuel vapor, as it attacks it & causes crazing. You'd want to be careful of splattering or dripping when filling a T-18 tank.

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John Evens
Arvada, Colorado
T-18 N71JE (sold)
Kitfox 7 SS N27JE