Oh, if you use hardener, you NEED a supplied air respirator. The hardener will coat the inside of your lungs and decrease the ability to pass oxygen to the blood. Effects are cumulative and essentially non-reversible. That "tough" coating is just as tough in you as on the outside of the machine. And contrary to what some un-informed people may tell you -- carbon filters WON'T take that stuff out.
that's a huge over simplification, to the point of nearly being wrong even.
while there is no presently supplied cartridge that is 'rated' to filter isocyanates, the actual particulate portion of the vapor will for sure be grabbed by the multi stage respirators.. that leaves the iso gasses.
at that point it's not a coating issue.. it's a concentration / sensitivity issue.
if you are sensitive.. it's a problem. I know guys that have walked around a freshly painted tractor and had bad reactions from the outgassing of the curing hardner. no more vapor in the air.. purely voc's boiling off got them.
if you aren't sensitive.. well.. you aren't. on the flip side.. I know guys that paint with only a vapor and particulate filter and have done so for 40-50 ys.. some people just aren't bothered by it.
kinda like the people that smoke for 80ys and never get sick, then others never smoke and die of lung cancer from limited 2nd hand exposure.
I usually get a high end cartridge rated for hydrogen sulfide, that.. or a NBC rated cartridge from govt surplus.. I'm pretty sure it's hard to beat a current spec NBC cartridge..
I'll also add that I'm apparrently one of those people not sensitive to isocyanate compounds. I've been using them 15 ys and neary a reaction.. first couple years I wore a n95 mask...
soundguy