[Namssorg]

Hi guys-

Some of you know that I'm an industrial designer - and I have a pretty neat design side project I've been working on recently that requires creating a mold that I'll eventually use to create thin-walled reinforced concrete parts. The process is very similar to casting fiberglass.

I'm familiar with making molds and the casting process, but I haven't actually had a lot hands-on time actually doing it. Something I know lots of you HAVE had plenty of practice at!

Just wondering if anyone has some good suggestions on what type of silicone mixtures you've found to be fairly robust and work well for the price. I'll likely mess up a few of these before I get it right- so I'd like to order a pretty big amount of material and want to get the most bang for my buck. Maybe some of you know a good brand to use, or a good place to find this stuff cheaply online.

Any help would be much appreciated- and as soon as I have some progress to show, I can't wait to show you what I've been up to.

[jackdoud]

Silicone and cheap don't go together in the same sentence unless the word "isn't" is between them. The way to pay less for silicone is to work out exactly what you need and how much of it before buying anything so you're not stuck buying more.

Personally I've mostly used Smooth-on products, they have a wide selection, good customer service and are relatively local to my area. I know others here use other company's products.

[CaptCyan]

I agree and disagree with jackdoud.

Smooth-On is the way to go but silicone molds will not hold up. What you want is this....

http://www.smooth-on.com/Urethane-Rubbe ... index.html

It's made for casting concrete. It's about the same price as silicone. Nice thing is they have a calculator so you can estimate how much you will need.

[Demon Vice Commander]

I've also used Smooth-on products before, and they are quite good. Like Jack said, they have excellent customer service and know their products extremely well (with hands-on experience). They even helped me find a distributor to get a slightly better price on the materials I needed.

[Namssorg]

Thanks guys- I think I'll try the Smooth-on stuff - I was assuming silicone was the way to go, but the urethane seems like it might be perfect for what I'm doing. Less delicate, for sure.

Any suggestions for what shore hardness? I guess to a certain degree that depends on my parts...

[ThrowingChicken]

I like 30.