For my birthday last year, my kids bought me an Alumilite Casting Kit; the really nice one. I had mentioned that I wanted to give it a try; I admit I was left scratching my head on exactly what to do with it, though. I did want to have a try at casting; I just didn't have anything in mind to cast at the moment. That was 7 months ago. Until a couple of days ago, it sat on my shelf unused.
I was mulling over filler piece ideas for my TEOTWAWKI project. One of the ideas I came up with was dragon's teeth, you know those big concrete anti-vehicle things. Nothing says war zone more than they do, right? So I set out and made a piece with three of them on it. As I was sitting there looking at it, contemplating how to paint it, I was struck with the idea that it made a perfect piece for me to try and cast, so I broke out the kit.
(This next part is going to be old hat for those who have done casting, before. My hopes are that any novices will see how easy it is and give it a try. Plus I like hearing myself talk...or type as the case may be.)
The first thing I did was make a mold. I ended up using all the RTV Rubber supplied in the kit to make the mold. RTV is short for "Room Temperature Vulcanizing"; meaning that the rubber cures at room temp; no special curing processes needed. To actually, make the mold, I made on open top box big enough to hold what was now my master. I sealed the master with clear varnish, and affixed it to the bottom of the box. I then mixed the RTVR per the instructions, and poured. I removed air bubbles that had formed when mixing the rubber, by placing the now filled mold on my table, then taking my jig saw, turning it on and holding it against the bottom of the table. The vibrations caused the bubbles to float to the surface. It would probably be easy to make a vibrating table with an old palm sander.
I was able to remove the box after about 4 hours. I let the mold cure over night. The discoloration in the pic are due to two things. The grey is the clay I used to seal the inside of the box and the white is due to not mixing the RTVR thoroughly. Neither one of which caused an issue. Next time I make a mold, I am going to use something like pink foam to act as a filler, so I don't use as much RTVR.
Below, you can see more detail on the finished master, with a couple of 25mm minis for scale. I am going to put a couple of the casts under the knife and add some battle damage to them. These will definitely work on my PA table. If I did 28mm WWII, they'd work perfectly there, too.