dangers of breathing superheated air

Those figures are sure cute. The dry throat might just be due to breathing warm air, but the fluffy white powder says you're burning the zinc coating off of the bolts and possibly breathing some zinc vapor, which is not good for you. I'd look for a way to ventilate better, or try removing the zinc coating (of course, acids and such have hazards of their own). Alternatively, since it looks like you do this a lot, you might consider using uncoated hardware.

-Tom

Depending upon what you are brazing or welding, there are a number of chemicals that are being produced by the flame. Working with brass, there is always the zinc fumes that happens and that is pretty nasty for the lungs. The borax fumes are not nice either. You may want to consider using a mask to keep the gasses out of your face and a fan to blow the gasses that are formed away from your face in addition.

-- Bob May Losing weight is easy! If you ever want to lose weight, eat and drink less. Works evevery time it is tried!

Um... burnt gas from an O/A torch is entirely CO2 and a little H20 vapor (steam), plus whatever shmutz from the work. As it rises it mixes with ambient air, cooling it and gaining some oxygen. With all the CO2 it will feel suffocating to breathe, which is reason (1) why you'd tend to stay out of it. I doubt there's much wind in a garage, so the air will rise straight up. Unless you've got a real akward setup, I doubt you need to stand directly over the work, so you'll be okay. (Reason (2).)

Besides that you aren't breathing the stuff anyway, even if you did it should be cool enough by a few feet above the work, and even if you did breathe in hot air, I suspect it would burn your throat before it would do anything bad to the rest of you.

You mention breathing apparatus... that mean dusk mask, respirator..???

Tim

Little blower motor from hairdryer, thick hosepipe connected to it, to a place with clean air.

A lightweight hose goes to a dust-mask. Blows air over face and keeps your eyes clear, as well as keeping breathing air clean.

Tom

Why thank you :>

I've smartened up since then, I first place the bolts in the wood-pellet stove for a while to burn off the zinc. At least, I'm assuming that coating would be burned off after half an hour or so..?? Anyone disagree?

My goal is to find a source for recycled (read: funky) metal parts to really make something special.

I saw someone wearing a regular dust mask while welding, that's the kind of equipment I was thinking of, low-tech stuff like a bandana or an electric fan placed close by.

Thanks all for the replies. Adriaan Gerber

On 10 Dec 2003 16:59:29 -0800 in rec.crafts.metalworking, snipped-for-privacy@yahoo.com (Joe) was alleged to have written:

A quick dip in hydrochloric acid (muriatic acid from the pool supplies) would get rid of zinc with less chance of changing the heat-treatment of the bolts (if any.)

As long as 'that place' actually has clean air that is a good way to go. A change in the wind could make that air supply into something you don't want to think about. I am a great believer in a filtered-supplied air system. These are not cheap - starting around $600. But one only gets one set of lungs/liver/other stuff so what's economy got to do with it? Ken (who has, and continues to do, stupid things)

Breathing Zinc fumes can get you something known as metal fume fever - fever, dizzyness, flu-y stuff. No fun. I thought you had to actually vaporize the zinc for this to be a danger, something welders had to worry about, but it apparently happened to me when machining a big run of galvanized parts on a turret lathe many years ago (they did get pretty hot...). Stumbled home and when I came back I told the boss I wasn't gonna do that particular job anymore.

mickey

Here's a good rundown on fumes and gases in welding, including zinc fumes, and some info on protecting against them (from 3M in the UK):

Here's the minimum mask that will protect you. I've worn them, they aren't bad:

They sell for around $2/ea in boxes of 10 or 20. If you're not in a rough industrial environment, one of them will last you a while.

You can get several PDF manuals on this mask from 3M in the US.

There are better ones, but I found this one to be fairly comfortable -- and cheap. No more tanking up on milk to cure fume fever.

Ed Huntress

A mask is good. Something like a 3M 3000 half mask is cheap, fits well, and has replacable filters. It's a lot better than a disposable mask. Make sure the filters are the right onews for metal fume, and stick a particle filter over the top to make them last longer.

The real fix though is to get some airflow across your bench, sucking at benchtop level from the back of the bench. Cheap surplus fans and gas stove flexible fluepipe can achieve a lot.

Don't weld zinc either. It's easy to shift and unpleasant to work with. Chrome, some stainless, and especially fluoride silver soldering fluxes are even worse.

-- Die Gotterspammerung - Junkmail of the Gods

I should have made clear that this is only for nuisance dusts and irritants. For nastier stuff, you want to pay more attention to exactly where you take the air from, as well as to preventing interruption of supply.

$600 is a big, big chunk of change for quite a lot of people.

It's quite possible to make a perfectly good system for most cases (it'll be less convenient) for a small fraction of this.

It should of course never be used in cases where the air inlet can be compromised by really nasty stuff, or where malfunctions can generate CO (I'd personally avoid using a compressor, but use a blower), or where if it fails, you can't safely exit the area without it.

For most stuff, like sanding nasty hardwoods, welding galvanised steel, painting, fiberglass, it's just fine.

Thanks for all the suggestions. I sure did not quit smoking only to be poisoned by metal fumes off my bench..

Adriaan Gerber