






⚡ Cast like a pro, fast and flawless every time!
Smooth Cast® 300 is a premium liquid urethane resin designed for quick, bubble-free casting with a convenient 1:1 mix ratio. It cures in just 15 minutes into a tough, bright white plastic that’s easy to machine, sand, and paint. Ideal for professional prototypes, sculptures, and special effects, it resists moisture and mild solvents, delivering reliable, high-quality results with minimal prep.










| ASIN | B004BN7G0E |
| Best Sellers Rank | 642,318 in Home & Kitchen ( See Top 100 in Home & Kitchen ) 2,062 in Sculpting Moulding & Casting |
| Brand | Smooth-On |
| Compatible Material | Plastic |
| Customer Reviews | 4.7 4.7 out of 5 stars (1,121) |
| Grit Material Type | Plastic |
| Grit Number | 300 |
| Grit Type | Fine |
| Item Dimensions | 18.8 x 15.2 x 7.9 centimetres |
| Item Weight | 907 g |
| Manufacturer | Smooth-On, Inc. |
| Material | Urethane |
| UPC | 751635476417 |
| Unit Count | 1.0 Count |
S**N
Awesome
Very good bought lots of this and will buy lots more easy to work with and great results all round
C**G
Pefect casr first time
I had tried another brand of resin and had lots of issues with it not setting or only working with one type of silicone. There is no problem with this product; I mixed, pored and after 10 minutes had a perfect copy. Will use again.
A**R
Five Stars
Good buy. A little expensive. But works as moulds .u have to work fast and accurate
J**N
very good
very good
A**T
Very sensitive to the mixing ratio, but great when you get it right
This comes as two liquids which you mix together 1:1, and then pour into a mould. It hardens to a bright white plastic over the next few minutes. When you manage to achieve the correct mixing ratio, you get a smooth, hard plastic, indistinguishable from what you might get from injection moulding or similar. It's really good as long as you get that mixture right. Where it's not so good is when it's difficult to get that mixture right. I'm working with really small quantities, which means that any error in the measurements is a much larger fraction of the overall amount, which in turn means I'm less likely to get good results. It's very difficult to tell what you're going to end up with just from the liquid mixture alone. I've had a couple of pieces come out absolutely perfect, but I've had a lot of weird, sticky messes too, and the odd hollow shell. Another thing to bear in mind is bubbles. It's very easy to introduce bubbles to the mixture, which will ruin your piece if you don't get them out. The mixture is also viscous enough that it doesn't easily fill small holes in the mould, so you've got to be careful about making sure you get it in all the little pockets without trapping any air in there. Anyone experienced with this sort of thing will doubtless be fine, but as a beginner I found it difficult to get a consistent result. I think, if you can, it's probably best to work in larger quantities and do a lot of pieces at once, that way you reduce the risk of getting the mixing ratio wrong. It's a lot easier to get exactly 30ml of one liquid and 30ml of the other than it is to get exactly 5ml of each... Does depend on you having sufficient things that you want to cast though, and as a beginner, just starting to experiment with this stuff, I've only got a few things I'm interested in casting at this point. Next time, if I only have a few things to cast, I'll try to mix the liquids by weight instead of volume, and see how that works out.
M**E
I like that this cures really fast. Worked great for my mask project.
S**E
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
M**O
Perfect
J**A
The item is as discribed and it’s way above the expectations
J**F
Takes only minutes to cure.
Trustpilot
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