Respirator

[ElBichoMalo]

I have some simple (one would think) questions about fiberglass and respirators. I use my respirator when using polyester resin, but that's about it. I have been using a dust mask for sanding/grinding cured glass. Lately I have been using the respirator for all just because it is more comfortable.

So, question is, how do you really know what you need the respirator for? The filters I have are for "organic vapors"...but what exactly does that mean? Any and all organic vapors? I find that hard to believe. And what products have vapors that are defined as organic? I have searched online, and nothing seems specific?? Even MSDS sheets don't really seem specific??

Also, what is the real service life of the filters? The package/3M website don't even say. Is it safe as long as you can't smell through it?

One of you experts care to educate me? I'm sure I'm already dead, but maybe you can save someone else...