As some of you may know, I used to work for a prop shop manufacturing magic tricks/illusions for some big time magicians like Doug Henning and Siegfried & Roy. Granted, my main job was to sweep the floor but the boss, Les Smith, soon realized that I had some mechanical skills instilled by my father. My father, the dentist, never shied-away from tackling a difficult project from repairing teeth to customing the interior/exterior of the family van to rebuilding the engine of an MG Midget. Everyday after sweeping the floor I was put to work building props - sawing, soldering, grinding, polishing, and sewing - anything to complete the prop. Well, I've always been fascinated by one prop building technique that I never learned - molding and casting plastic resin.
Inspired by Harrison Krix, an amateur prop builder at http://www.volpinprops.blogspot.com/, I decided to try a relatively easy mold/cast job - a life size Lego Star Wars Blaster. Anyone with a boy under 10 knows how popular this item could be. After scouring the Internet I found that no one had attempted a life size version of the ubiquitous blaster. So why not me?
This was also an excellent project to turn on my new Jet mini lathe. I chose soft, finely grained basswood because it's easy to shape but in the future I might choose maple because basswood tears out whereas maple is easier to machine.
My template was simple - a blown up picture of an actual Lego blaster. I glued up the shaped pieces, applied some car body filler, and sanded the piece over and over.
Using alternating colors of primer I was able to sand, pinpoint any flaws, then fill and sand them out.
I wet-sanded the final black coat of primer to 1000 grit. Then I waxed the master with car wax. Heather was surprised by the smoothness of the master's exterior. It felt like plastic but it was just wood, filler, and paint. Next time I mold an item I'll take the grit even higher because the silicon picked up every minor scratch of the 1000 grit sand paper.
I built a simple mold box, filled it with clay, and embedded the master half way. The dots you see are simply registration keys so that the two halfs of the mold would mate well together.
I filled the mold with Mold Max silicone, nice and slow in the beginning to make certain that no bubbles formed on the surface which might come through in the casting. Then I filled the rest of the mold with more silicon.
After the silicone dried, I flipped the mold over and removed the clay. Leaving the master in the mold, I applied a "release agent" (a must) and then poured the second half of the mold with silicone. After the second half dried, I peeled the mold apart and took out the master. Using white plastic I "slush cast" the first copy. The white resin set up in about 10 minutes.
I bought some black resin which sets up very quickly and molded a black version. The black resin has a shorter "open time" and heats up quickly. My first black copies came out warped. Apparently, the heat initially expands the mold and, as it cools, it sucks the sides of the gun inward. I solved the problem by demolding the copies just after they hardened (still warm to the touch) and drilling a tiny air hole to allow the hot air to escape as it cooled. The pink copy is simply white resin with a little red dye.
Above is a pic of an original Star Wars Mini Fig (Clone Trooper) holding a blaster - tiny, huh? My life size copies usually come out with a little flashing attached. I trim it off with a razor blade and polish the plastic with an electric buffer and jewelry buffing compounds. Voila!
