concrete pot mold

by kokabog Apr 30, 2019
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Here are a few things I've learned wrestling with casting concrete out of PLA/PETG over the past year...

I use silicone-based mold release, you can find it on Amazon, but PAM, petroleum jelly, or vegetable oil could probably yield similar results.

Depending on the concrete, the curing process may get too hot for your PLA, PETG will warp less.

If you design a thin sleeve that fits over the inner insert (similar to a condom) and print it in TPU you'll have a much easier time de-molding the middle piece, the hard scaffolding insert pops right out and you can peel the TPU away from the walls and wiggle it free. If you can't print TPU easily try 3D Solutech's Flexible Filament, it's not quite TPU but it's flexible enough and does the job and is much easier to print than a brand with a lower shore rating.

Check out CSA cement (Cement-All at Homedepot), it pours wonderfully and cures in under an hour (but puts off tons of heat). I much prefer it and it's finish to the portland-based cements and mortars. It's also lighter in color therefore giving you more tinting options when using dyes. (BTW, liquid RIT Dye for clothing works about as good as the Quikrete branded pigments, which are limited)

Using a good mold release and cleaning the molds after each use I've been able to reuse PLA/PETG/TPU molds many many times over, 20-30 castings at least. A wire brush will remove any buildup of concrete, wipe it down with a rag to dry, and spray it again with a release agent and it's ready for another pour!

Good job here, I like your designs, especially this one! Keep up the good work :)