At 06:30 PM 5/2/04 -0600, you wrote: >Right, Harry, I understand. But just because he hasn't heard of it doesn't mean it couldn't be done. I know it can be done because my caster has done it. I would call the fellow back
Vance, You'll have to accept for the moment that I thoroughly investigated this man's ability and willingness to do what I need done and have determined that he CANNOT do the job I need done and is unwilling to attempt it. When presented with a foam pattern he said he would remake the pattern in wood, make a matching conventional core box, and sand cast it conventionally. At that point I saw no point in continuing the conversation. He did recommend and alloy which was neither coppery red (which I didn't want) nor a pee-yellow (which I SURE don't want), but of course I promptly mislaid my note where I wrote down the alloy. >You invest it, burn it out and cast it just like any other meltable pattern. Partly so. As you know, the basic process of investment casting preparation creates a master and mold which is reusable and repeatable. Unless you have enough demand to warrant a female blowmold, into which urethane beads are expanded, lost foam does not. It's one whittled pattern at a time, which makes it viable for live steam work only if you have a one-off, or a number of very simple (ie quickly carved) patterns. That's a substatial potential difference in the labor required to produce multiple parts. If I want a backup casting, or the first pour is bad, I'll have to whittle another pattern from scratch. Regards, Harry