(Hi All, new here from “another” forum)
I’m looking for a material that is very light, strong, hard to puncture, doesn’t stretch and airtight - but without the epoxy applied. Anyone know of such a material? I’ve looked at alluminized Mylar but it’s too prone to puncture.
Any pointers much appreciated.
What is it being used for?
Containing a vacuum!
Well, that’s as clear as mud. 
There are dozens of companies making vacuum bag materials. Most of them stretch, some more than others. Generally the thicker materials have less stretch. Good ones are very puncture resistant. Resins don’t adhere to them. They’re stable at very high temperatures. Solvent resistant. Obviously airtight. Light weight.
Thanks for that! 
Mylar (or generic equivalent) seems to be the most common. I’m wondering if there is a way to make a very light weight kevlar airtight? I suppose I could try covering the kevlar in Mylar… s’pose it’s not an everyday requirement…
Ther is a company just down the hyway from me that makes airbag material, very strong very lightweight, very expensive. If you are doing the same mold over and ver you may want to consider doing a custom silcone “bag” If you have flanges “just” spread out the silicone and let cure, peel it off and voila custom bag. you have to use the proper stuff and the proper thickness but it is reusable.
I’ve been making the reusable bags for about one year now. I ike the reuasable aspect since I am not throwing money away everytime I vac bag a job.
It is still not clear what you are trying to do but you could use latex rubber or Silicone rubber and add layers with Kevlar, fiberglass or woven gaugse as reinforcements.
If you could give us more information on what you are trying to do and the application, then we could help you more.
Where do you get your reusable bags? That’s something I might be interested in. How many uses do you typically get out of a bag?