I wanted to be able to make a few of these, so I molded the one I made
out of foam. I used some great stuff from smooth-on for this,
brush-on 40 and plasti-paste. If you're unfamiliar with these
products, you can use many other things. I personally love the
brush-on line for casting anything made of polyester resin, it seems
to let the surface cure tack free, unlike silicone, I'm told it has
something to do with the silicone pulling heat out of the resin.
The mold is rather straight forward. I did a couple things I'd
change, but overall am pleased with my mold. It did have a few
things to watch out for, the first being moisture (read water) in the
clay used to make the dividing wall. Regular old water based clay,
you can use whatever you can find such as WED, for this. After
the wall is built, I sealed it with a couple coats of crystal clear,
which helped smooth the surface of the battery further also. After
that, a coat or two of shellac on the clay to seal it completely. A
spray of mold release over everything and I was ready for the brush-on
40.
Nothing unusual here really, just followed the directions, mixed in
a little pigment so I could be 100 percent sure it was mixed well, and
brushed and spatulated on 3 layers to build up the thickness.
After that was allowed to cure, about 20 hours, it was crystal cleared
again, then mold released. The plasti-paste was mixed and spread
over the mold to form the support shell, after keys were set in place.
The mold was flipped over, the clay removed, and cleaned off of
everything. This half was crystal cleared, shellac on the wall,
and the process repeated for this half.
That wrapped up the mold. Some things I would change, I would
divide the rear half of the support shell into two pieces down the center.
Another thing to be careful of is to make sure you get mold release
over the entire surface of the battery, I had a few spots where paint
and "glowder" stuck to the mold, but it was easy to remove.