The original gun. It's a gas blowback BB pistol, so it has a real slide action. Very cool.
Filling in the undercuts. This is to keep the silicone from getting into places that would make it difficult to remove the original object from, but I went a little overboard from what it turned out I actually needed. The silicone is wonderful.
More undercuts. Lots of little places.
Setting the gun in the clay bed. This is the most tedious process, because you want to get a very good separation line, but not something that will show up in the final detail. Lots of adding clay a tiny bit at a time, then using tiny tools to push it into place.
The clay walls built up to hold the silicone. Smoothed with denatured alcohol and a finger or two.
The first pour. Note the air bubbles. I didn't do the vaccuum degassing step, mostly because I don't have a vaccuum chamber handy. Yet.
Another angle. You can see how thick the clay was. I used a lot of clay. I think I bought 15 lbs.
The first silicone has cured, the clay removed. Cleaning the clay was a lot harder than I anticipated.
Building up the dam for the second half of the mold. If you look closely on the back of the gun, you can see the clay actually touches the gun body. This is to allow a "hole" in the final mold that I can pour the casting material into.
The second half of the mold poured.
The two halves after curing. On the right hand side, you can see the pour hole.
Just a bizarre green glowy picture.
Immediately after removing the first cast. Notice the flashing that needed to be trimmed. The material is an A/B CFC-free foam urethane. I decided to try something weird and mixed in some Gorilla Glue. It worked extremely well... I ended up with foam overflowing the mold a whole bunch.
Same thing, other side. Notice the warping. I clamped the mold too tight without full support. Learn for next time.
And the finished product before painting.
I'll get some pictures after painting it later.
The nice thing is now I have a reusable silicone mold, so I can make lots and lots of these if I want to.