New Mold Tutorial: Formlabs Form2 Pattern for Silicone Molds

Hi there, my first post here in the Forum. I wanted to share our new Mold-Making Tutorial Video featuring the Form 2 Printer.
Watch how to turn high quality SLA 3D Prints into Patterns for building short to medium production silicone molds. We then cast high impact polyurethane parts to use in demanding applications like Electric Skateboard equipment. Let me know what you think and please don’t hesitate to ask any questions. We’ve also created several other video tutorials centered around 3D printing in a YouTube Playlist.


I have a new found appreciation for our mold making guys in our warehouse! Thanks for the video, it was very informative!

1 Like

Thank you for your informative video. The instructions were very clear and concise.

On average, roughly how many parts do you get on short to medium run productions?

PS. I also liked your simple but effective curing station.

Thank you for sharing the great video. It helped show me what I have been doing wrong with my 2 part molds.

1 Like

Great question. It depends on a few variables (geometry of part, draft(s), undercuts, quality of surface needed, etc) but we see anything from a couple dozen parts up to 50+ parts if the part is very simple. We also see a difference in mold life depending on if you are casting rigid materials vs soft elastomers. You can also help increase mold life by using a proper mold release.

1 Like

re: Curing station. I should post some detailed pics of what one of our talented Tech Guys did on ours. It works great and is indeed simple. Just some PVC sheets and mirror plexiglass on the inside.


Do you have any tips for creating threaded studs in the mold for securing brass thread inserts in the finished part? I could use pressed in inserts, but molded inserts are much stronger.

1 Like

True. If you haven’t tried these inserts, they work really well for pressed inserts: McMaster-Carr

For molded inserts there are a couple ways you can approach it. The quick/easy method is to simply cut a short length of all-thread rod and sink it into the pattern with a majority of length protruding out. When you mold the silicone around the pattern, you will form a pocket for inserting the all-thread piece later. Apply some mold release to the all thread and insert it into the silicone pocket. Screw the insert onto the all-thread, close the mold, and cast the part. When you demold later, just screw the all-thread stud out and repeat the process.

For a more production oriented method, you’ll need to make/machine or 3d-print some custom stepped plugs that hold the threaded stud and insert once the mold is made. The stepped feature makes a definitive depth gauge and adding a slot on the back allows you to simply unscrew the holding fixture out of the tool prior to demolding. See attached pics for a better idea.

Threaded Insert Tool.stl (448.1 KB)

1 Like

Excellent info, thank you! That was the direction I was going.

Which inserts at McMaster were you referring to? It just linked to a main page of inserts. The helicoils or can you post a part number? I have used those in FDM prints with good results in the past.

It is obvious that much thought needs to be put into the mold design as well as the final part for good casting results.

Sorry: Twist-Resistant Hex-Shaped Inserts

Yes, doing a little more work on the front end of the tool makes it much easier when you are trying to pop out several parts. But also, you can use these little pins and tools on other projects since they don’t really wear out. Sometimes it warrants doing it the quick and easy way if you just need a couple parts, but for repeatability and accuracy it’s good to do it right up front. Sort of our approach with the 2-part mold making techniques instead of 1-piece “cut-molds”. It’s good if you only need a quick part or two, but the amount of flashing clean up around the parting lines will eat up the time saved after a dozen or so parts.

I would say that the fill port and vent placements are the most critical in setting up a tool. A lot of mistakes and misconceptions are made in this area. For example, filling from a low point and venting from high points is key, and then add to that tilting the mold to prevent flat ceilings for bubbles to collect. It sounds so simple but it’s not intuitive if you are new to doing this.

We sell a bunch of these nifty items shown in the videos after everyone kept asking where to get them; LINK. Also, if you need to see any cured samples of materials (silicone or polyurethane) just ask me! Our goal is to show how to expand the use of the 3D printer and do it right so you’re successful the first time. We’ve been around the rapid prototyping business for 40+ years so the average consumer is now getting to benefit from techniques and technologies perfected over the last few decades. :slight_smile:

I realize it has limited applications, but have you tried printing molds for smaller parts directly in the flexible resin? It wouldn’t work well for some things as it is fairly stiff, but it would eliminate some steps. I would imagine mold release would need to be used liberally.

I have not, but only because we haven’t run the flex-resin in our machine yet. Would be a good thing to R&D in the future :wink:
Having said that, in theory all you would need is a good layer of mold release in place to ensure parts release. We did make a video on using 3D Printed molds from FDM printers and much of the same approach applies. Making molds in the rigid Formlabs resins would be similar. Enjoy the info on 3D printed molds, as well as some gratuitous Quad-copter action:

Great video. I make silicone molds from my Form2 masters all the time for my company I love the fact that Form2 masters require very little work before they are ready for molding.

I’ve used BJB products in the past … really good stuff, I recommend them. Your competitor in Pomona (won’t mention any names) is just a little more convenient for me at this time.

1 Like

Thanks, you make some nice looking parts (checked your site). Do you also metal spin cast some of those dainty things? I can imagine how nice it would be to print your parts on the Form 2. I made a Ford Mustang and F-150 Raptor in Z-scale on the F2 from Ford OEM STL files and they were incredible.

Nice video!

Fun detail, to hear a form 2 printer running in the background at several moments in the video :wink:

1 Like

Very nice tutorials! I’ll subscribe…thanks so much for sharing!

We use polyurethane molds for making wax for glass casting. Some of the similar techniques, but interesting to see it put to use in another application.

1 Like

Thanks for the shout-out on todays webinar, Jordan!

You’re welcome, thanks for the great content! :slight_smile: