On 1/3/14 6:13 AM, Patrick Greenlee wrote:
As regards having the wind or a fan at your back to avoid breathing the
fumes. Not a good idea. Not a sound idea aerodynamically speaking. Wind
in your face is not the best either. Take a look at the videos on YOU
TUBE showing welding. Huge plumes of fumes are generated. Wind at your
back generates eddies and vortices on your lee side (face and chest
side) and puts you in the position of breathing in significant
quantities of fumes. It is far better to have the wind or fan produced
breeze blowing sideways left to right or right to left to clear the
fumes. Having the breeze come from several degrees to the rear but I
wouldn't exceed about 15 degrees. The idea is to have the fumes blown
away and not recirculated around your head.
As a practical matter, a fan over your shoulder works. Or having the
wind over your shoulder.
I think the general idea is "position yourself so you don't breath the
fumes".. Fortunately, they are quite obvious.. it's not some stealthy
invisible gas.
Zinc poisoning is not a casual minor thing to be ignored. If you do
breathe some zinc fumes one of the symptoms may be a metallic taste I
your mouth. The non-ferrous foundry workers casting zinc and welders
welding galvanized material that I have observed always drank
significant quantities of milk as a partial cure. I did some Google
searches and saw where milk was recommended too. I am not a medical
doctor and am not advocating a medical procedure, just reporting what I
have observed. YMMV
It sure isn't something to be ignored.. BUT, if you're talking about
someone tack welding half a dozen bolts to some rebar, the amount of
zinc involved is pretty small. And given the speed at which most hacker
welders work, there's going to be some time lag in between the welds to
allow the smoke to clear, if only because the time required to walk
around to the other side of the rebar cage or whatever.
I frequently weld galvanized steel. It has been decades since I had
"that metallic taste" in my mouth from it. I do take precautions to
avoid breathing the fumes.
yeah.. I have an acquaintance who does a fair amount of welding on
galvanized sheet metal ("corrugated metal roof" and "water tank" kinds
of applications).. His approach to these things is decidedly less
casual, but then, he's doing it every week, and for long periods, and in
close spaces. He has a bunch of ventilator fans with flexible ducts on
them.
P.S. auto-darkening hoods ROCK!!!
Truly.. Better living through technology for sure.
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