Re: CASTING Plaster Investments vs. Ceramic Shell?????


Bramblebush ForumsFAQ

Posted by John Stricklin on February 11, 1999 at 21:14:37:

In Reply to: Re: CASTING Plaster Investments vs. Ceramic Shell????? posted by bpfink on February 10, 1999 at 00:28:36:

Bruce --

I appreciate your response. I was afraid my posting would get missed since it showed up so far down in the list. You make several interesting points which may be of more help than you might imagine -- namely that you use wet molds into the kiln, etc. I will want to discuss this more later. I do want to use the mold at 1400-1500F not C. My objective is to infiltrate a high melting point metal powder held within a mold. I want to infiltrate with an alloy which melts in the 1400-1500F range. I have been told that Aluminum & non-ferrous casters get away with plaster molds because of the short duration exposure time during pour at non-ferrous rather than ferrous melt temperatures. Yet USG & others tell me that the mold will disociate at longer term exposure well below my target temperatures. I sence words of wisdom in your remarks as to fillers & reinforcments. If I mix fused silica into my plaster will I approximate the #262 R&R product which is a plaster-silica mix sold for Aluminum and similar casting?? If so, can this mix tolerate a 1hr heat-up cycle, 1hr hold and 1hr cool down?? (as contrasted to the shorter exposure during conventional Aluminum casting "into plaster"). I do like your comment of starting the heat cycle with a wet mold. I can tolerate a single use for any individual mold since I plan 1-off type processing. Your note seems encouraging if I add sand or other material to the plaster. Am I reading too much into your comments?? (or should I just switch to investment materials to shell my parttern?? I really prefer plaster if it will work). Thanks for your interest in my non-conventional process objectives, John Stricklin

Follow Ups:

Bramblebush ForumsFAQ