cotman

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Got a couple of questions. 1) noticed a lot of planes with cowls have a hex like wrench coming out of cowl. Is there something that goes on the carb to allow you to do this. 2) Have to alter my cowl to fix muffler. Want to re-glass the part I'm going to change. Can I use wax to make the shape and glass over the wax. I assume the epoxy and glass won't stick to the wax. Thanks for any help or suggestions

khodges

My Feedback: (1)

First question-- the "wrench" sticking out of the cowl is to adjust the high-speed needle valve on the carb. It can be a small allen wrench, or a piece of stiff wire fastened to the adjuster by a set screw. Allows adjustment of the carb to fine tune the top end without having to take off the cowl. You want the engine barely on the rich side at wide open throttle to prevent overheating and seizing.

2nd question-- wax is okay as a mold, but make sure it isn't on any surface you want the epoxy to adhere to, and as the epoxy begins to harden, it will heat up, possibly melting the wax and causing the shape to deform. Using some type of hard foam, such as pink board or florist's foam blocks is better, it can be carved to shape and then cut out easily after the epoxy cures.