Working with Silicone

After doing some research, I decided to go with Smooth-On's Rebound 25 brush-on fast setting silicone, however my local supplier did not have any in stock. Instead, he suggested I use Mold Max 30 (which is a slow setting, liquid silicone designed for pouring) with a Thi-Vex thickener to make it more suitable for vertical application. He had plenty of this stuff, and I was too impatient to wait for him to order Rebound 25. So, I bought the Mold Max 30 gallon kit.


Mold Max 30 is the kind of product that requires absolute precision; I had to go out and buy a food preparation scale for measuring amounts when mixing part A with part B. (For information on preparation and usage of Mold Max 30, have a read here).   


Because silicone mold-making is a procedure that can take several days, it is IMPERATIVE that there are NO MISTAKES during any of the steps! And perhaps the most important thing to NOT screw up on is the application of a release agent to whatever it is you are trying to mold prior to siliconing. I've watched a number of videos on YouTube where a guy spends days making a mold, does not apply enough release agent, and ends up destroying not only the silicone skin, but the original mold as well. Epic fail.


So, before I even started mixing my silicone, I sprayed both molds with mold release; I spread it with a brush, waited 5 minutes as per instructions, and sprayed another coat on. 

IMG 1244

The first coat I applied was not thickened with Thi-Vex. I mixed the silicone, poured it onto the molds, and distributed it evenly over the molds with a brush. I let this dry for 24 hours (the recommendation is 14-16 hours, but because of work and other engagements, the waiting time in between coats was usually longer).

IMG 1214

I applied a second coat with a few drops of the thickener, and let it sit for another 24 hours or so. Third and fourth coats had the maximum recommended amounts of thickener, with the waiting time between these coats being 16-ish hours.


The last thing I did was apply globs of silicone in an "X" pattern top of the molds. These would act as "registration keys" for easy insertion into/removal from a fiberglass support shell that would allow the rubbery silicone to maintain shape during slush casting.

IMG 1216
IMG 1217

I am not going to get into the details on how to make a fiberglass support shell; in a nutshell, I put the master object inside the silicone mold, flipped everything over, sprayed the outside with mold release, and applied fiberglass. And after several hours, viola: a hard shell that fits perfectly over the silicone.

I was now ready to cast the new helmet!

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Version 3 Molds

  • Working with Silicone

Rotocasting

Painting

Completed Version Masks

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© mynocksden.com 2014. Disclaimer: I do not claim any right to any of the characters or parts and components thereof which I have recreated and showcased on this website; all articles I have made are "fan made" props only, made for myself as a hobby. I have no affiliation with Lucasfilm, LucasArts, BioWare, and/or any other parties to whom respective intellectual property rights may belong.