Smooth-On Cast 305 Urethane Resin (Trial Unit)

I’ve used a lot of casting resins and urethanes and this is one of the best Smooth-On has to offer. I like it better than 300 (2 min pot life and 10 minute cure), as 305 has a manageable pot life of 8 minutes and a cure time of 30. These characteristics make it an ideal material if you need to produce several casts in a day, while providing adequate time to mix and pour into your molds. The plastic is bright white as advertised when cured and durable. I’m producing very small castings (4-6 grams of material at a time) and the 1-1 volume ratio is very easy to mix and follow.

This resin worked very well for my project. The resin itself is quite sturdy after casting and was easy to measure out before casting. I highly recommend!

It works quite well if you use both a vacuum to de-gas and pressure-pot to pressurize. I still have a few bubbles float to the top or get stuck on mold features, but otherwise this is the best option I have found available on amazon. The working time is short, I only have about 3 minutes (of the 7 minutes) to get it mixed and in the mold, but not as short as the 300 version, where I only feel like I have one minute (of the 3 minutes). I did eventually switch from this to the Task 9 version to mix it with color.

Smooth-On is the leader of that pack when it comes to mold making and plastic casting, it really is the best, the only problem is they make expensive stuff! But you get what you pay for, as always. That said, you don't get a lot of product for 30 bucks, you get 2 medium sized bottles of part A and part B, you can get a lot of little castings, or a few medium sized castings, and only 1-2 slightly bigger castings. I think it's a real crock that they can't offer a medium sized option...you can either buy this stuff in a trial size that is $30, or a giant gallon size that is $150 dollars...that's unfair to me, there should be an option for $50-60 bucks that would be a bigger, more valuable step up. As for the people that complain about smell? There is none, this stuff does not smell that bad at all, regular Elmer's glue smells worse than this. If you are precise, careful and just take your time, this stuff will work beautifully and cast what you want. If you are hasty, sloppy and impatient, you'll probably screw up, don't take it on the product because of user error. Apply yourself, experiment with tiny casts before you cast big ones, and you'll have great results. If you have any holes from bubbles, just get some epoxy filler and fill the holes in manually, it's not the end of the world. I casted a zombie head and he had a hole from a bubble right under his chin, I filled it in with epoxy clay and smoothed it out and you'd never know it was there. Be creative! Good product, but kind of a rip off for how you can only get little bottles for an affordable price, but once again, you get what you pay for, good stuff is expensive, crap is cheap.

Very easy to work with great results, don't let it get old