3D printed molds for concrete pots

[dlqfpv]

Thought about this and should’ve asked about the hardness vs pH as water in Florida can be pretty hard.

Cheers
DSD sends

My water in SoCal is also very hard. Calcium spots on everything.

 

[Weta]

Nice work. Been wanting to try myself for some original pieces.
I line my concrete pots with Bitumen, a few watered down layers first soaks in then few undiluted ones. I normally give a recoat when repot.

 

[Orion_metalhead]

Wrong post lol...

 

[oranjeaap]

Ah yes. The pH and hardness debate. Basically on every plant / bonsai / aquarium forum I've read for the past 10 years people are always eager to bring that up when concrete is but mentioned. You could easily settle this by running some cheap and easy tests using aquarium testing kits or urine dipsticks etc. But I don't recall anyone ever actually doing it.

 

[dlqfpv]

You can try a concrete releasing agent or vaseline or something similar to get better release from the molds.

I used vegetable oil, Several videos on concrete molds from 3d prints used this, my molds are clean, the concrete didn't stick to the inner surface, just the outside where i didn't use any oil. Its just some of the contours need some better designed draft angles, something I am learning more about

 

[mountaindr3wz]

This is great there's a podcast talking about 3D printing and pot making somewhere. I think it was the black pondo podcast. How about using TPU for as its a little flexible to remove the mold to prevent areas of concern from cracking?I use TPU on my 3D printed drone parts for some give when i have an oh shit moment lol. Also a vibrating plate to remove the bubbles while you're filling it up.

 

[dlqfpv]

This is great there's a podcast talking about 3D printing and pot making somewhere. I think it was the black pondo podcast. How about using TPU for as its a little flexible to remove the mold to prevent areas of concern from cracking?I use TPU on my 3D printed drone parts for some give when i have an oh shit moment lol. Also a vibrating plate to remove the bubbles while you're filling it up.

I do a lot of printing in TPU as well. I have a drone business my own drone frames and 3d parts for them. I thought about TPU, but I was worried when the mold was full it would bow out. I guess you could make them 2 parts a TPU inner mold and an Stiff outer mold. But the molds were not that hard to remove, just in a few spots. I think most of the failure was concrete related. I had not worked with concrete before so I am not very familiar with it.

 

[htownbonsai]

Hello all, just wanted to share my journey (so far) into making concrete bonsai pots, using 3D printed molds. I am showing the results of my first two attempts. I have a lot to learn still. These almost ended in disaster, but I was able to save them. So your thoughts and suggestions are appreciated.

I started of in Fusion360 designing a few bonsai pots. I went with one very simple rectangular pot and one with a little bit more curves and edges.
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After I had some pot designs I liked, I designed a mold around the pot to be later 3D printed. As I designed the molds I went back and adjusted the pot designs to account for draft angles, printer bed size, and how I was going to fill the mold with concrete. The larger pot needed to be broken into more pieces for printing, and it actually made it easier to de-mold in the end. the smaller pot i may go back into the file and break the side into 4 pieces for easier de-molding
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Here are the 3d printed molds after being used, they ended up holding up very well. only one little piece came off of the smaller pot, it was a post to make a hole for a wire tie down.
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I used cheap Quik-crete brand concrete from the hardware store and i sifted out the large aggregate and large sand.

Below are my results of this experiment. These pots almost didn't get this far, but I didn't want to give up on them, and they ended up working out, at least for now.
This first pot, my mix was a little too thick, I left more sand in than with the second pot, and I used less water. When it came out of the mold it fell apart into 5 pieces, I used some epoxy to temporarily hold the pot together, then filled in the crack with more concrete. The base of the pot was very thin, so I used more concrete to build up the inside which is why it looks rough. I did use a random orbital sander to help get bubbles out, but with the concrete being so thick, it didn't work as well as intended. I am planning on doing a little touch up with sand paper on this and possibly a little paint or wash.
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This second pot i added some finely sifted concrete to the mix to remove some of the heavy sand grit, I also added more water to make it easier to poor the mix into the mold. The mold came out better but still cracked into a few pieces, i used some adhesive and more concrete to repair it. I added a brown wash as a little test, but wiped most of it off. I also lightly sanded the sides of the pot.
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Some things I am thinking about:
Using glass fibers or wire to strengthen the pot.
Using a cement specific for molds, or mix my own cement, sand mixture instead of sifting
Modifying the molds to to make de-molding easier the large pot was easy, the small pot because i used two sides instead of four was harder.
I don't have to worry about frost in SoCal, well maybe one night a year, every decade or so.

I am open to suggestions, thoughts, etc. Sorry I don't have pictures in progress, I just have before and end as things got a little messy in the middle and didn't have anyone to help me take photos

This is awesome, i have done this once, but was unsuccessful. my pot crumbled, i still need to figure out the right mixture. maybe i'll try with a smaller pot.