So a few of you have been tuned into the search for Bronco knobs. I had been trying to make a few clones for myself as well as clone some old radio and other knobs for projects. Here are a few of what I made earlier this week. I am pretty pleased. These are drilled, tapped, ready to rock. The one I soaked in a jar of coffee for a few days to see how it would do.
Cool stuff! Not long ago I was interested in figuring out how to cast stuff and spent a bit of time looking into it, but never pursued it. description or pics of the process would be fun to see.
The white is least expensive. The other options are clear and then you tint them with transparent or opaque dyes. I am mostly sticking with Smooth-On stuff. It is known to be best. I built a pressure tank with a 2.5 gal paint pressure tank. I bought a set of canisters for my food saver vacuum sealer. I mix the rubber in solo cups, vacuum out the bubbles in the silicone then pour the mold. Once I have the mold made I cast it under about 50 psi . I also have had much clearer results with the transparent stuff when I warm the molds on a coffee cup warmer.
I thought you only really needed the whole vacuum process when the piece has all sorts of undercuts and fine details. Even then I've only ever used a vibrating table for really complex pieces and they've come out fine.
I had problems with bubbles in molds and casting. The vacuuming the silicone before pouring it helps a lot and pressure in casting is pretty much essential with this resin. It is solid and fine to handle in 30 minutes.
Black looks good so far. I did a transparent red one and a clear with a seed as a marker for a buddy. I'd like to get into polishing the clear stuff. Can't be hard.
If the clear stuff has casting blemishes try painting over the area with gloss acrylic varnish, or even modelmakers water effects (it's basically a pre-mixed transparent resin).
Solid metal castings would be pretty rad with those templates. 
