ORIGINAL: MarkGrabowski
OK, I'm laying up a cowl for a pattern plane I'm building. It has cheeks and a deep nose with recesses in it. I've a question on the order of layups...
I'll need to place small piece of cloth in the cheeks and chin and the flat area behind the spinner in order to bend it to the sharp angles I'm faced with....
should I layup these first and then lay down the larger parts (about 4 larger pieces of cloth) or should I lay down the large pieces first and then finish up the smaller parts...
I did a trial run this weekend and wound up with a bunch of air pockets and sharp corners that the cloth lifted away from...
Mark
Let me suggest that after you lay down some reinforced paste in the corners, you then use a heat gun to gently touch the paste. Any air bubbles will heat up and pop, leaving a smoother corner with no bubbles in the finished part.
For really deep or sharp stuff, let the first layer of paste set-up a liitle, then put in a second layer of paste and then proceed with the 0.6 oz cloth in the whole mold. The 0.6 oz stuff minimizes pinholes in the finished part. You should let this layer of epoxy set up before putting in the reinforcing layer of glass.
I also usually spray my mold with KlassKote primer before any lay-up work is started, as speed mentioned. PartAll wax accepts the primer extremely well.
Almost forgot, when waxing the new mold, wax a couple layers and buff them, then wait an hour before applying the last 2-3 coats of wax. The wax works better at releasing the part. Lately I've only used PartAll with no PVA. PartAll releases well on its own, even from plain unprepped wood, believe it or not. I pleasantly surprised me to find that out, since one of my landing gear molds has a little exposed wood on it's flange
For heating smaller molds during the winter months, I have a cardboard box set-up on top of an oil radiator type of electric space heater. Works very well and I have heat control from the radiator's thermostat. Even slow curing epoxy like ProSet 125 with 229 hardener cures in 12 hours as opposed to a couple days