Parts Casting Materials and Supplies?

Dan,
I just recently did my first molds in resin and here is what I discovered. I bought from Micro-Mark their "Complete Starter Kit." $65 US. It included their One-to-One rubber mold liquids, their Cr-600 casting resin, mold release, Kleen Klay, and mixing set with brushes, mixing containers. I mixed up too much resin the first time and had to waste it. But I was very happy with the M4 road wheels (two of them) that I molded. No air bubbles or other problems except that I tore the mold trying to get one wheel out. No big deal though as I think I just needed to cover the area better with casting release spray. Here is the link: http://www.micromark.com. Use part number 82698. The silicone mold material is an A & B liquid that you mix in equal parts, stir and pour into your mold box or mold holder (no heating or anything-very simple). I used a bass wood box and had some leakage but no big deal. I left it over night to cure, but the directions say a 4-6 hour cure time. Note: I did not make a full mold (both top and bottom) as the wheels were going to be attached to the tank and backside detail would not be seen. So I just embedded the wheels a little deeper into the silicone. The casting resin is a 7-minute pot life (it stays liquid for that long) so you have time to mix, pour, etc. It is an A/B liquid as well, mix and pour. Also, their were no real fumes from the resin, as stated on the bottle. I let the mold sit for about 45 minutes (the directions say they are ready in 30 minutes) and pulled off both sides of my silicone rubber and the parts looked good.
Now their are a number of other types of resins and silicone molding materials, but I cannot speak to their use. I used the same technique (mold making and process) that Shepard Paine outlines in his book, How to Build Dioramas. One type that I'm thinking about trying, as it is less work than building a box, etc. is to use a RTV Silicone putty that Micro-Mark sells (part# 81853). It's a mold putty that you "press the putty around your pattern. After 5 minutes, remove your pattern and your mold is ready to use. Fill mold with resin, plaster, wax...anything." This sounds great, and for wheels and generally small parts this might be a great way to do it. I also disovered that if you are molding parts with deep undercuts, micro-mark recommends their Ten-to-One High Tear-strength rubber (#82663). It is more durable and last longer with repeated castings. I hope this helps and please share as to your success as I would love to expand this process as I am very pleased as how easy it is to complete a mold and casting.
Dmod

Micromark... Alumilite and Bare Metal Foils All have starter sets available. I've been using Alumilite for most of my castings........as i can get it at the LHS

I started doing this a few months ago it took a couple of tries to get anything worth keeping but it's not bad once you get the idea down, my first batch I tried to do one part molds, once I changed to two part molds it worked fine. I use a 10-1 RTV silicone for the molds that does not require a mold release, it costs a bit more but the guy at the shop pointed out how much the mold release costs so it really isn't any more expensive plus no worries about mold release. I'm using a polyurethane resin to cast with. I've used it to make some wheels and sirens, I've fininhed making some clay rolled hose sections which will be my first casting of something original (the others were casts of model parts).

I got my stuff from TAP Plastics, I have a store nearby and the manager is a modeler so he was very helpful. The cost was about the same as what I saw online but I can get quantities up to 5 gallon buckets if I really get ambitious which does result in a rather significant cost reduction.

It really isn't that hard to do but be open minded and expect your first couple of tries to fail, then if you get some thing nice your first try great, but don't get discouraged if it takes a few attempts. Alot of the material can be recycled, you can grind up the silicone to use as filler on the outside of molds and you can use misformed or excess resin to fill in larger castings so failed tries are not a total waste. I've got a box I started of bad castings I might use for a junk pile at some point, lots of 1/2 cast wheels etc that wouldn't look bad sticking out from underneath something.

Thanks guy's. I'll go with either Alumilite or the Micro-Mark kit. Can't wait, should be fun.

I've also made a "pressure pot" to help prevent the bad castings...... working great so far!!!

Aaronw, I never really thought about what to do with the excess "waste" of my resin. That is a great idea in regards to using it to fill larger castings. I've never done anything bigger than wheels, but I will give this a try.
Dmod

I have heard that you can use "PAM" cooking oil spray as a mould release - haven't tried it myself as I am still trying to figure out this stuff

wibhi2:
I wonder about using PAM, not because it wouldn't work, but the the propellant in PAM might dry out and hurt the silicone rubber mold (it causes discoloring on some surfaces). If the mold is a once use, then probably not a bad deal. Let use know if you try this or someone else has any experience with this.