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Making a Carbon Gear for my Vector 40

I first made a mold using Windy Urnowski's method which can be found on one of his many instructional DVD's.


Materials: 1" Carbon Tape (~.20/inch), 12K Unidirection Carbon Tow(~.10/ft), Mold Release Paste ($5.25), PVA Mold Release Liquid 8oz ($7.25), Epoxy Resin A 32oz ($23.70), Medium B-Side Hardener 8 oz ($12.50)

Additional Material: Breather/Bleeder Cloth, Release Film, Kevlar or Figerglass Tape

Source for Carbon Fiber and Resin


Before doing any lay-up, cut up all of the lengths of carbon tow and tape you are going to use. I used about 32 segments on this gear.


Wax and buff the mold with a good car wax or Tap's Mold Release Paste. Then prep the mold with 3 coats of PVA mold release agent. Allow it to dry between coats.


Secure you mold to the workbench. I use an old gas can to give some working height. This will allow the excess tow the drap down freely. You are now ready to start mixing your epoxy resin for the lay-up.


Paint a layer of epoxy on the mold. Lay-up one segment of tow at a time.


Work the epoxy resin for top outward on both sides.

Make sure all the tow strands of fiber become saturated. If resin becomes too thick, you can use a heat gun to thin it.

Work out excess epoxy as much as possible.

Carbon Tape on the last lay-up. If is benificial to lay some woven carbon or kevlar fabric in high stress areas to prevent splitting, especially where it attached to the fuselage and wheel hub.


Poor-mans release film: Wax Paper Let is cook over night.

 





Hope it comes out of the mold.

Some finishing may be required. If surface has major defects or not to your staandard, you can alway add more epoxy resin to it. Use release flim to get a better finish. A poor-man method is to use packing tape as a release film. This will give you a nice shiny finish.


Here is the result of my second gear. I added Carbon Tape to only the high stress areas, the mount and hub area. Added one layer of 1" woven kevlar tape. This gear came to to .9 oz, and its is lighter and stiff that the Bolly 40 gear. It's is ready to install!