Okay, so that finishes up the sculpting part, but our helmet is still not finished. Even with all the smoothing we've done, there are still a lot of flaws and surface textures that we need to get rid of to have a finished piece. Plus we need to create mounting points for the visor to attach to.
And that means we have to do a waste mold. Why's it called a "waste mold"? Because you use it just one time and then throw it away. So obviously we want to do this as cheaply as possible while still getting a good casting. The method I'm about to show you can be done with a single $30 sample kit from Smooth-On, or any comparable product.
So, here are our materials.
I'm using Dragon Skin 10 for it's elasticity, but most any platinum silicone will do. It's possible to do this with tin cure silicones as well, but they tend tear rather than stretch, so I prefer to stick to the platinums.
The little 3oz Dixie cups are our primary measuring tool and we will be pouring up each layer using only these. The 'Silc-Pig' adds color to the otherwise transparent silicone (more on this later). The last element not pictured is 'Thi-Vex' or comparable thixotropic additive.
For the first layer I poured out equal amounts of parts A and B of the silicone into our Dixie cups about 3/4 full (or about 2 oz each). I add a small drop of blue pigment to part B and mix thoroughly. The silicone is then brushed onto the sculpt and then "dabbed" all over to pop bubbles and push the material into the cracks and crevices.
It's then hosed off with compressed air repeatedly to further pop bubbles and any drip off is scooped back up and ladled back on top. After it settles down and smooths out this is what you get, a thin but pristine coat of silicone on your part.
Gotta get back to work, but I'll be back with more.
