Stuck Epoxy Blank in 3D Printed Mold

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jbgifford

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Cave Creek, AZ
Had a friend print a 4 wide mold. Tried it with epoxy resin and now i can't get the blanks out. Tried drilling hole in the bottom for compressed air. I did apply mold release. And suggestions on how to demold would be appreciated. Thanks.
 

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Unfortunately 3D printed molds are not easy to demold, especially with epoxy because resin gets between the print layers (those little ridges you can feel) and it holds on. You can try putting it in the freezer to see if it releases but most likely you'll have to cut your blanks out and ruin the mold. Printed molds aren't meant to be used like hdpe or silicone molds. They are either one time use molds or you have to take other steps to prepare it for use. When I print 3D molds for resin I leave the bottom off and line the inside of the mold with clear packing tape. Then I hot glue it to a flat piece of wood or plastic also covers with tape. This makes it easier to demold, and resin will pull away from the tape easier to reuse the mold (after it cools off). If you try to demold it while it's still warm, the printed walls will deform.
Best of luck!
 
I have used a torch to soften then the print so I can remove hidden magnets on failed experiments. A few seconds of the torch and the mold will soften, of course this is destructive to the mold.
 
JohnU said:
Unfortunately 3D printed molds are not easy to demold, especially with epoxy because resin gets between the print layers (those little ridges you can feel) and it holds on. You can try putting it in the freezer to see if it releases but most likely you'll have to cut your blanks out and ruin the mold. Printed molds aren't meant to be used like hdpe or silicone molds. They are either one time use molds or you have to take other steps to prepare it for use. When I print 3D molds for resin I leave the bottom off and line the inside of the mold with clear packing tape. Then I hot glue it to a flat piece of wood or plastic also covers with tape. This makes it easier to demold, and resin will pull away from the tape easier to reuse the mold (after it cools off). If you try to demold it while it's still warm, the printed walls will deform.
Best of luck!
Click to expand...
Ugh. Should have done more homework forst. Thank you. Does Alumilite resin fare better than epoxy?
 
jbgifford said:
Ugh. Should have done more homework forst. Thank you. Does Alumilite resin fare better than epoxy?
Click to expand...
I use alumilite urethane in 3d molds often but if I want to demold them instead of turning them off, I coat the inside with clear tape. A heavier tape around 3 mil works best.

Here's a video of my process using 3D molds to cast a small bowl blank. The process is the same no matter how big or small the cast.


When I cast pen blanks, I cast a larger block and cut them to blank sizes. I get more character in them compared to pouring one blank at a time.
 
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JohnU said:
I use alumilite urethane in 3d molds often but if I want to demold them instead of turning them off, I coat the inside with clear tape. A heavier tape around 3 mil works best.

Here's a video of my process using 3D molds to cast a small bowl blank. The process is the same no matter how big or small the cast.


When I cast pen blanks, I cast a larger block and cut them to blank sizes. I get more character in them compared to pouring one blank at a time.
Click to expand...
Well this tells me I've not perused your youtube channel for a while, there are more videos to watch!
 
I feel your pain and frustration. I once froze a drill bit in an acrylic blank by drilling on the drill press at a high speed. I am a quick learner.
 
I tried using my 3D printer for molds and it was an epic fail - the layering of 3D printing is not smooth and it basically becomes little teeth stacked on top of each other holding whatever is cast into the mold. Using epoxy just makes it even worse at it tends to stick to everything even silicone molds. At this point I only consider a 3D mold as being single use, and turn them away in process. Not what I hoped when I invested in a good 3D printer, but it does come in handy for a lot of other stuff.

Kevin
 
In my experience if you want to 3D print any type of reusable mold, definitely go with TPU. Shore hardness of 95A is stiff enough to hold it's shape while still being pliable to bend enough to get the casting out. Plus it stands up to the heat really well. I have a couple single blank molds that I printed in 2022 and they are still holding up great. Just hit it with mold release before casting and it's good to go!
 
ghostshadow said:
In my experience if you want to 3D print any type of reusable mold, definitely go with TPU. Shore hardness of 95A is stiff enough to hold it's shape while still being pliable to bend enough to get the casting out. Plus it stands up to the heat really well. I have a couple single blank molds that I printed in 2022 and they are still holding up great. Just hit it with mold release before casting and it's good to go!
Click to expand...
Can you tell me a bit more on your success with TPU? I have a Bambu P2S with the AMS and I've read lots of issues with this printer and TPU - already know not to put it in the AMS, but the horror stories on feed issues have kept me away from trying TPU. However, being able to use it to make some custom reusable molds has a lot of appeal, as its why I bought my printer originally. Appreciate your thoughts.

Kevin
 
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