smooth-on silicone question (oomoo 30)


Jr Member
Wasn't sure if this was the correct place to post so forgive me if it is not.

For making a silicone mold, i am going to order Oomoo 25 online since it has a quicker cure time than the 30. However my local Blicks store has 30 in stock and there was a sale, so i got some until i order the 25. Does anyone know of a way to speed up the cure time for the 30? 6 hours is a long time obviously and if there is a way to shorten that I would love to know. Or do ya just gotta wait it out and deal with the 6 hrs?


Mr. Nagata

Sr Member
In the time it takes you to order the additive, your mold will have cured and your 25 will have arrived. :lol


Active Member
You can add more catalyst but overtime they may effect the life of the mould and can make it more brittle. Although as you bought it as a kit you probably have just enough catalyst to do the full kit.

The other thing is to put it in a hot box, e.g. a box with a heater in it. But be careful if it is to warm the silicone can begin to rise in the middle a bit.

But like everyone else is saying, I would just use it like normal and leave it overnight


Master Member
You can heat the mold to try to kick it faster, but why not pour it before going to bed and demold the next morning?
Plus 1 on that. Also I just made some new molds using a slow cure silicone and even after degassing I noticed there were some small bubbles. Because of the slow cure time, these rose to the surface and popped. Now I have solid bubble free molds.


Master Member
Six hours? Impatient much? The stuff I use takes 24 hours, I just let it sit overnight.


Sr Member
my advice: don't use oomoo! it's super super soft... you can damage the cured silicone with your finger nail as you demold the part. unless there's some chemical reason you need tin cure silicone, stay away.

try their moldstar 16. it cures in under an hour, and is very very durable. it's platinum though, so it is sensitive to latex, polyesther resin, phase of the moon and what color shirt you wear while mixing it.


Jr Member
thanks for the responses, much appreciated.

yea I guess i am a bit impatient but I have a lot to get done,

ill look into moldstar ^^

if anyone else has any other silicone suggestions I am totally open to hear them.

Daniel Nelms

Sr Member
I wouldn't try to rush it, in the future you could try something like mold star 20t that stuff cures pretty quick.
If your building a two part mold with WED clay the water in the clay seems to really kick the silicon fast FYI.

We use some stuff that takes 16+ hours to cure, so 6 isn't too bad. Better to be safe than sorry when it comes to a mold, silicon is expensive stuff.


New Member
If you're just starting making molds, slower is better.
You'll be amazed at how quickly the time passes and how often you mess up. :)

I've done a dozen molds with Oomoo 30. I just work on sculpting the next piece while it cures. (Or sleep if it's that time of day...)