September 12, 2018 at 7:20 am #68969
So my buddy that does clay and pewter casting for tabletop miniatures asked me to draw draft up a Karate Kid Cobra Kai drawing and cut a master mold for a belt buckle or coin or whatever, I dunno, he’s an artist type. Here’s the test piece in MDF.
1 user thanked author for this post.September 12, 2018 at 9:30 am #68989
The detail on that thing is great!September 12, 2018 at 2:04 pm #69018
Don’t you want a mirror image of that for a mold?September 12, 2018 at 4:18 pm #69045
I might have to mirror it, I might not. This was just a 3″ diameter test cut for my purposes and it will all depend on what medium he’ll use for his finished items. I don’t know if he is going to make a clay slip casting mold so that he can do coasters or whatever, or if he wants to do a silicon mold for pewter. I might even do some wood and stain or poured and layered color epoxy coasters. I’m certain that he doesn’t want MDF for the master mold.
1 user thanked author for this post.September 13, 2018 at 4:05 pm #69182
Doing a mirroed relief in aluminum block would make a great casting. Especially for miniatures which is something I wondered if the LowRider could do. Ever carve aluminum?September 13, 2018 at 6:28 pm #69188
I’ve never used my MPCNC for aluminum. I have the original version of the machine and it’s not nearly rigid enough to suit me. I work for a small machine and fabrication shop as a drafter and CNC plasma operator so if I need anything metal, I don’t do it at home. My part of this mold will be cut from either graphite or MDF coated in polyurethane and then my friend will take it and make a clay slip cast mold or a silicon epoxy mold.
I don’t think aluminum would be a suitable material for a pewter mold. When casting metals, the mold should ideally be as close to the temperature of the casting metal as possible and insulate as best as possible to make sure that the liquid metal flows into the smallest crevices. If the mold is too cold or dissipates heat like aluminum does, then the liquid metal won’t flow into the smaller outermost parts.
In fact, I would worry that pewter might actually solder itself to aluminum in certain cases. Especially anywhere that the oxide layer is scratched to allow contact with clean, non-oxidized aluminum. Plus, making silicon molds allows for far more detail and far more forgiving relief angles when designing a mold… but I’ve gotten myself going on a tangent 🙂
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