Spaceballs The Costume Belt Buckle

The buckle was relatively straight forward to make, though it marks my first foray into casting. I first settled on a 3.5" diameter for the buckles. Fortunately I had a spare PVC ring from my Imperial Binders that was just the right diameter. I started by filling in the ring with oil based clay. I later found out that the clay I used (Roma Plastilina) contains sulfur which can retard the curing of silicon, more on that later. After filling in the ring I blocked out the general pattern of the buckle.

Blocked Out

I started with the head for a few reasons. It's in the center of the buckle so I could work from the middle out, it's the hardest part and if I couldn't get it to look right I'd have to scrap the whole thing and figure out something else.

Rough Head

Once I got the head looking good I move on to the wheatstalk/laurels as this would delineate what space I had to work with for the lettering. The words wound up being the biggest pain in the ass. I used a combination of 3-4 tools to hand carve them into the clay. They didn't come out perfect but I think they're good enough.

Finished Master

With the sculpt complete it was time to try casting it. As I mentioned the clay I used contained sulfur which will prevent silicon from curing. This was easily fixed by sealing the sculpt with a coat of spray lacquer. For the mold I bought Oomoo 30 casting silicon from Smooth-on. I would have preferred Oomoo 25 as it has a faster dry time but my local supplier was out of stock and I didn't want to wait for the next shipment. I built a mold box out of foamcore and packing tape and taped it down to a piece of scrap styrene.

Molding Buckle

Six hours later it was time to see if I'd have to sculpt it all again. Fortunately the cast came out perfectly. The PVC ring I used was much higher than the buckle needed to be so I added a tab to the side to give myself a reference when filling the mold.

Finished Mold

To cast the buckle I used Smooth-on's Smoothcast 305 liquid plastic. With a 30 minute cure time I can crank out a couple buckles in an evening and it doesn't require mold release.

Finished Cast

A quick run on a belt sander to smooth down the back and trim off the tab and it's ready for paint. I started with a coat of black then bright aluminum which was then dulled down with a satin clear coat. There are a couple imperfections that could be filled in before painting but I figure if anyone is looking that closely at my crotch I have other problems.

Master, Mold and Cast Finished Buckles

submit to reddit