Smooth-On Smooth-Cast 300 Liquid Plastic Compound Smooth-Cast 300 by Smooth-On, Inc.

This product is so easy to use, doesn't have a bad smell so can be used indoors. You do have to be quick so be well prepared with moulds to use

Perfect

Worked perfectly for my needs. Very little bubbling even when pouring it directly into a two-part thin walled cast squish mold with very little venting built into the mold. Even though my casted part is probably 1/8 of an inch thick at its thickest point, and probably half that at it's thinnest, this product is still very durable. Surprisingly. I was expecting I may needed to get the Smooth Cast Task series product over the Smooth Cast 300 to get what I needed for such a thin cast. First attempt at a cast I tried degassing the mixed resin. Spent one minute mixing. And one minute or so degassing. Which should have left me with one final minute of potlife. Nope, within a 3 second period between having my eyes on the resin in the chamber, I look back and see a very hot eruption of resin that instant cured into a soft foam in the shape of magma pouring out of the cup like a volcano lol. Lesson #1 learned. No degassing. First cast I used release (really just cooking spray) and black pigment powder. And it came out horrible. Finish was rough and textured, and the color was grey although I used a ton of black pigment. And ultimately it made the cast extremely brittle and it broke in two places while sanding/trimming. Lesson #2 learned. No additives, and avoid release agents (or at least particularly non-cast specific release agents). Without any additives or any release (still released perfectly fine without any chemical release) it came out very smooth and very durable. It also sands amazingly well. Doesn't clog up sanding paper, sands down powdery and easily. Also the cast was a motorcycle helmet spoiler that isn't sold separately anywhere. Was a very expensive handmade Portuguese carbon fiber racing helmet. I decided to learn about molding and casting and made myself a new one using a spoiler to the same model I bought for my girlfriend as a gift. Think of, two birds one stone lol. Gift + master for my own spoiler. For my very first cast, being so complex as it was, and being such an amazing success.. I am completely happy with myself and the results of the various products I've used. Will say though, silicone mold making is definitely much more difficult than the resin casting process haha. Especially two part molds making with non-flat masters.

I used it to mold HO train parts. I mixed powdered pigment in one part and then mixed the two parts for a minute and poured. I had very few bubbles and I was able to reproduce some very fine details. The parts were ready to de-mold in about 10 to 15 minutes. I used a squeeze mold for some parts and an open mold for others. Both methods worked well. The product cures opaque white and adding black powder pigment gave me a finished product that was grey. I made about 200 small parts with this size. I used two separate syringes to accurately measure parts A and B then mixed them in a medicine cup.

Very good bought lots of this and will buy lots more easy to work with and great results all round