Recently I’ve had a bunch of people asking about using 3D Printed Molds to make cast parts from polyurethane. It’s still a fairly new technique but it can be very effective in certain applications to make parts quickly. There are some specific things to know about before jumping in to making 3D Printed Molds. We put together a fun video showing the making of a DIY quadcopter/drone which you can download files from our Thingiverse page: http://www.thingiverse.com/thing:1746672
With Formlabs SLA Molds the release procedures are identical. Any rigid mold needs to be treated correctly in order to get a good release. If you are planning on casting Silicones; you may also want to consider that UV cured resins can cause curing issues with Platinum Cure Silicones so an additional sealer like Krylon Crystal Clear might be needed.
Let me know what you think or if you have any questions!
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Saw you mentioned Cure inhibition with the Platinum RTV… Just a quick side note, I have actually experienced some with the tin also… Not as bad or drastic at platinum but was still cause for concern, Just sticky and it went away a day or so later after the part was removed. Just thought I would add that for people who are trying this out for the first time. Just a quick shot of mold release/barrier (I use ease release 200) and no issues after.
Interesting. It’s a good idea to sand and seal the surface regardless. Mold releases don’t really act like a true barrier so priming or clear coating is best on fresh SLA parts. There are so many variables to the process and UV cured resins are hard to pinpoint when they aren’t reactive anymore, so a good filling primer like this makes life really easy: https://bjbenterprises.com/index.php/misc-products/mold-kit-accessories/sem-high-fill-primer/
With so many people experimenting with 3D Printed molds for quick prototyping, this info can help save a lot of headaches. We’re getting a lot of calls after this issue happens so I’d rather get the info out prior to the mold disaster. 
LOL… Yea I discovered that after one of those 2am Pours when you’re brain dead and I forgot to coat it.
I am playing around now with printing my 2 part molds parts already “Clayed” up in the computer then just print both sides so I can just pour both sides at once. I use to machine my parts this way so Printing them should be no issue as long as everything stay accurate
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