Did you give latex a try?

Yo. Sorry, I haven't posted here in a while. Haven't posted anywhere in a while really, because I've been busy working my ass off.

I tried latex, it's not going to work. It sticks, it smells bad, it off-gasses inconsistently in the same way latex paint behaves.

I've had mixed successes with platinum cure silicone. First off, the stuff is expensive no matter from whom you buy it. It's also subject to cure inhibition, where it doesn't set up in the when coming into contact with certain materials, such as other types of rubber.

However, there are blends that are stretchy and durable. My record so far is making seven bicycle handlebars from a single pressure bladder before it finally ruptured. The behavior to avoid is what I call "tunneling", where your carbon preform deforms unexpectedly under pressure, and allows the bladder to expand too far in an isolated zone. This expansion can be held for about two hours.

The point is, if you're doing pressure molding with a bladder, and you're new to it, it can be super frustrating to identify ways that a well made bladder might get killed simply by asking it to do too-hard of a job.

I haven't needed to do it for vacuum bags myself yet, but I could totally see how the material would indeed make a fine vacuum bag. Something similar was a set of gaskets I made for some custom, very-small-size vacuum catch pots. Something you'll have to keep in mind with vacuum bag use is that this silicone has mixed behavior in terms of its abrasion and tackiness with other materials. For instance, mastic / tacky vacuum tape doesn't stick to this stuff at all. Might as well bounce off.

You can see the kinda parts I'm able to make with silicone bladders at the site I put up recently, http://www.regular.bike/