Welding respirator

[jclay]

I've been having some trouble breathing lately after getting back to brazing, and I'm starting to wonder if it's something to do with the fumes. Last summer we had really bad smoke out West, and my lungs didn't seem to be the same afterward, so maybe I'm just more sensitive now. I've used a respirator a bit, but haven't been sure if it's the right one. I think I'll get some of those 60926 ones to see if that helps. Anyone know if there's anything in particular to be looking for with a mask for brazing? My understanding was that the fumes from brass brazing weren't all that bad (though I would notice black soot from the torch after brazing for a while, so that can't be good). Silver flux is supposed to be toxic though, right?

Thanks!

Each respirator mfg will have an application chart for their cartridges that will indicate the proper selection for your service. I prefer a substantial shop exhauster with positioning so that I'm not/little exposed to the fumes. To me that's a mandatory, foundational item. Another option, an addition in my view really, would be a welding fume extractor that's positioned over/near the joint being worked but that can be fiddly unless you have a large hood over the entire brazing area. The position of my exhauster (near ceiling and adjacent to where I braze) is a MOL functional equivalent.

I use high speed rotary tools (burrs, abrasive wheels, cutoff disks) as little as possible but when I do, and aside from the usual PPE (eye and inhalation protection) I use my shop vac to gather/control/exhaust the debris while I'm working (at least when I'm exercising some wisdom); I position the nozzle, sometimes with funnels or other things on hand, to suck the debris directly from the cut and into the canister.

But for simply brazing I've found that letting my whole shop exhauster run, with windows open, takes care of that problem. If it's really cold outside I sometimes throttle it (via a rope attached to the 2'x2' door on the outlet) so the flow is reduced whilst still getting the fumes out adequately. My brazing station is below and a few feet away. You can get an idea with this photo: Flickr

The door is on the outside of the shop and a rope threaded to the inside allows me to cleat it at whatever opening I want.

[jclay]

At the extreme end of respiratory protection are supplied air respirators, like these: Respirators - Respirator Mask | Turbine Products

But if I had to wear one in order to braze I wouldn't be building bicycle frames. I cobbled together a functional equivalent for sandblasting and painting that's powered by my small shop vac. The filter gets removed, the canister, fan and all get washed & cleaned before deploying it for this service, and the hoses get flushed as well: Flickr

If I needed to use it even a few times a year I'd get a dedicated, purpose built unit like the ones at the link.

For non-cad based brazing, and where the situation permits doing so, I think that a well located whole shop exhauster with a substantial flowrate + airflow from open windows/doors at the other end of the shop + a brazing and body location so that the fumes are removed from your breathing zone (and of course the whole shop) expeditiously is probably the most cost effective, 99% solution.

Shoot, if I had to wear even a half face air purifying respirator (the ones with canisters, as opposed to supplied air units) in order to braze I'm not sure I'd find framebuilding to be a worthwhile hobby. I don't know, maybe I'd get used to it, but I prefer just getting the fumes out the door immediately. I have a hard enough time getting myself to wear a particulate mask when using abrasives (roll, sander, whatever); I do it, but I grumble, and I've decades of OSHA HAZWOPER training so there shouldn't be an internal argument.

As an aside, and re abrasives: I've noticed a chimney effect from my body heat! In a calm shop your body heats the air around you and it rises. If you're using, say, abrasive strips the dust gets entrained in the air that's moving up and past your face. Wear a particulate mask (and I hate them). Actually, I use my half face APR nowadays because the location of the exhaust valve doesn't fog my glasses as regular particulate masks do.