Hi Y'all
Finally something I actually know anything about!
A couple of general points. The fumes given off when welding galvanised
will not do you any good whatsoever. The fumes are toxic. Drinking milk
to line your stomach before welding galvanised will not give you immunity!
The inclusion of zinc (galvanising) in your weld will do nothing to improve
its physical properties and using filler to cover up dodgy welding is not
really the answer when working on structural body work.
As an ex welder, I speak from bitter experience that the effects of
inhaling fumes when welding galvanised. At technical college when I was
doing my training we referred to the resultant illnes as metal fever or
fume fever. The symptoms are similar to flu. The worst flu you have ever
had. You go hot and cold, you shake, you have a blinding headache. The
symptoms once they begin can come on very quickly and with considerable
vengence. You could go through the above in half an hour. Its not like
the kind of flu where you can still manage to sit through watching the
footie on the tv. If you have 'properly' you just want to die and if you
dont realise what the cause is may suspect you are dying! One of the
endearing features of 'fume fever' is that it has an accumulative effect.
After you have had it once, next time the exposure level required to bring
on an attack will be lower. Not that you will know when to stop as the
attack can, in my experience, follow anywhere between four and twelve hours
after exposure. As students we were told that the zinc absorbed by your
body concentrates in your major organs and takes years to disperse. How
true that is I dont know, but it seems to have a ring of truth when you
consider how the heavier metals build up in the body.
Some people say that they only work in well ventilated areas. In my humble
opinion, the level of ventilation you require to be 'safe?' would also blow
away mig shielding gas. Oxy acetylene or stick may be a better route.
Other people say they have been doing this for years and its never done
them any harm at all. It is worth remembering that kids used to play with
mercury because it was fun and it didnt seem to do any harm.
Are there any advantages to using galvanised sheet to make repair panels?
Probably not as many as you may hope for. When you weld the galvanised it
will burn off the protective coating any way. So you will need to clean
back the heat affected areas and prime, paint (and underseal) them. If
your preparation and painting are effective will the galvanising do that
much good any way?
One final point. It is not just galvanising that is harmful. Welding
painted components, especially powder dipped or coated ones can be equally
dangerous. Just about any form of electroplating can lead to fume fever -
chrome, nickel, bright zinc, cadmium.
I have no doubt that by now there will be a whole load of people reaching
for their flame throwers. It is just possible that they are also the
people we have all seen at one time or another, doing a bit of a welding
job in the summer with no overalls on, not even a tee shirt - just standard
issue shorts and trainers, frying their delicate lilley white skin with the
intense uv radiation from their arc welders. Ask any wleders you may know
about the joy of 'arc burn' and how quick you can get it.
Time to get off of my high horse and don my flame proof welders overalls!
Bye y'all
Dudley
ps please excuse typos etc
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