The Thirteenth Hour Podcast #279: Working on a Thirteenth Hour Custom Action Figure Part 4: Making a Silicone Mold and Shrinking with Mineral Spirits

This week, I’m making a silicone mold for the guitar I finished last week.  While the mold for the synthesizer is quite easy, this one is a bit more complex since I’m going to be trying a trick I learned on youtube with a video (below) made by Crafsman, who I support on Patreon.  (He has a lot of great resin casting and toy making videos; check him out!).  The trick here involves the use of mineral spirits mixed into the silicone with the idea that over time, the mold will shrink as the mineral spirits dissolves out, leaving you a smaller mold.  This effectively gives you the ability to shrink objects (in theory – I’ve never tried this before).


Since the guitar I made was a bit too big for Logan’s hands, hopefully, the technique will allow me to shrink it down by about 25%.   Here’s the video in more detail described by the Crafsman:

By the way, the one piece mold for the synth I finished recently.  Now it’s time to pour in the resin!


And the setup for the guitar mold seen from the top down. I ended up using a thin plastic box as an exoskeleton for the mold.  It was what I had lying around, though it didn’t have a flat bottom and the flexible sides meant it had to be supported from both sides, as shown below, where the body and most of the neck of the guitar are already submerged in silicone.  The toothpicks are meant as air vents.


The bottles on the sides are supporting the mold as it dries, so it cures straight (a consequence of me suing a somewhat flexible container).  Now, it’s a matter of waiting a few days for the mineral spirits to diffuse out of the mold to see if this actually worked.


Last week, a friend of the show and frequent guest / collaborator, AC of ACToyDesign needed some help for funding a surgery for his dog, Mooge.  In the span of the past week, Adam and Mooge actually exceeded their finding goal (click above for more info from Adam), so thank you to all that helped!

If you still have a cassette player, take advantage of the following deal and be transported to another world!  SALE!  While supplies last, grab Long Ago Not So Far Away on cassette!  Just $1/tape!




There are now Thirteenth Hour toys!  If you’d like to pick up one of these glow in the dark figures for yourself, feel free to email me or go to the Etsy store I set up ( and get them there.

If the past few months have got you needing a break, you may want to chill out to this 80s synth throwback track for a upcoming LP with the accompanying music video:

Empty Hands, the synth EP soundtrack to the novella, Empty Hands, is now out for streaming on Bandcamp.  

empty hands ep cover_edited-2.jpg

Stay tuned.  Follow along on Spotify!  There is also a growing extended Thirteenth Hour playlist on Spotify with a growing number of retro 80s songs.

Check it out!

As always, thanks for listening!


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