Relist: I still need help.
I sent an e-mail to Chris, but did not receive a reply. This being my first vist to your site and being unfamiliar with it I may have not responded properly to get the message sent to him. My message was essentially that in trying to be brief I didn't give enough information in my initial question. I have quite a bit of experience in making and using silicone rubber "blanket" molds supported inside fiberglass/epoxy shells (mother molds), which has been OK for prototypes, casting RTV urethane elastomers. I now need to make limited production molds for test markets, casting a more durable urethane which must be heated to 212 degrees (F) and cast into a mold which has been heated to 180 degrees. The fiberlass/epoxy shells which I am now using are insuitable, becoming soft and distorting at around 150-160 degrees, so I am gearing up to cast the shell molds in aluminum, still using a silicone rubber banket (liner). A further problem is that urethane chemically degrades the silicone rubber, necesitating that the rubber has to be re-poured after every 30-35 (prox.) urethane casts. I have heard from a source which I consider to be reliable that a swim fin manufacturer (Force Fins) was using Bondo to construct its production molds, and would like more information (preferably books, written publications or other in-depth treatsies dealing with using Bondo for gavity cast molds. Eventially I will need to progress into using all aluminum molds without the silicone rubber liner, but if it works, Bondo could be another option to expensive machined aluminum cavity molds. I didn't get any help from the Bondo people, but they did acknowledge being aware of some use of their product for molds and casting by taxidermists.

The links which Chris sent were new to me and may be of future value, but I really need techical help on the question of Bondo as a mold material. Any help you can provide will be greatly appreciated.

Thanks