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Member Since: January 6, 2010

Country: United States


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  • The wax casting wasn’t necessary. You could have done the initial print in PLA and then encased that in the plaster investment. The PLA could then be burned out in the same way that the wax was, although a bit higher temperature would have been required (could be done in the same furnace that you melted the aluminum in).

  • I didn’t see any tire tracks on the wall, but I’m sure SOMEONE is going to try using a bicycle on that speed trap!

  • 6MM != 0.25" You’ve used both to describe the bore of the pulley in the parts description. So which is it? I actually have some NEMA-23 motors that have a ¼" dia shaft, so these might be useful.

  • Well, that may be a bit harder to build than Adafruit’s “cupcade” but it sure looks nicer! http://scharkalvin.weebly.com/about-me.html

  • I made my furnace in a flower pot lined with concrete and perllite. The flower pot was stuffed into a large can that once held popcorn. The lid of the furnace was made in the lid of the can lined with a band of metal and has iron wire re-bar inside to help hold it together, again lined with the same concrete refractory. Haven’t yet tried to fire it up, I have a old hair dryer for the blower. I made two crucibles from empty propane torch cylinders (held them under water and opened the valve with a nail to make sure they were empty!) The hole in the bottom of the pot will allow any aluminum that might spill to drain out the bottom of the furnace rather than into the blow hole. Furnace will be run over a pit of dry sand.

  • You can use the same furnace that you melt the aluminum in as a kiln for melting out the PLA. I’m thinking of trying my own foundry work based on the books by Gingery, using his charcoal fired furnace.

    I do see your point about the silicone mold, but now you have two sources of shrinkage to account for when sizing the original!

  • Why not, if you print it in wax (and add the wick after the fact)?

  • Remember the nut starter tool that came with every Heathkit? That could be 3d printed. (wonder it it’s on thingiverse?)

  • That will actually work someday. 3D printed organs made from stem cells are a very possible technology.

  • That would actually work, and you don’t need to make a silicone mold. Print the object you want to make a mold of in PLA and then encase it investment made of a mix of plaster and foundry sand (I don’t know the right formula). Add sprues made of PLA or wax to provide the input trails for the casting metal. After the investment hardens place it upside down in a kiln to burn out the PLA and the wax. Something like 300C should do it. Now you have a ‘Lost PLA’ mold to pour your molten aluminum in. You’ll have to make the original somewhat over sized to account for the shrinkage of the aluminum after casting. I think it’s a few percent, google for the exact figure.

No public wish lists :(