Sally or Dick Taylor wrote:
> Grego--Very interesting! I'm wondering if this would also be the case if
>using (MIG) welding wire that is flux impregnated, rather than using the Argon
>gas as the deoxidizer? I've also submitted this question and story to
>"SNOPES" to see if it's myth or has substance. My cynicism lies in brake
>cleaners almost instant evaporation, yet apparantly stayed around during the
>heat and air of the welding process.
> Old enough to doubt, young enough to learn!
>
>
Yes, brake cleaner does evaporate quickly, and has a very low vapor
pressure. However, many items have microscopic or larger pores where the
liquid can be retained due to surface tension, and if you've looked
carefully, most brake cleaners leave a very light film on the surface,
composed of less volatile components.
So, yes, it's a problem. Compounding this problem is a long-known
phenomenon of welding byproducts collecting and concentrating under the
welding hood, because of its shape and lack of ventilation. Many a case
of welders coming down with early emphysema due to breathing in burned
flux products, not to mention the odd instance of welders coming down
with cadmium and zinc poisoning after welding galvanized and
cadmium-plated parts.
As for your question about flux wire being safer than argon, nope, I
doubt it. It's the heat of the arc that is the principal cause of the
chemical effects. Argon is not a deoxidizer, strictly speaking. It's
an inert shielding gas, and doesn't contribute to the chemical
processes--flooding the area with inert gas simply keeps oxygen in the
atmosphere away from weld area (and provides for a slightly more stable
arc when the gas is turned into a plasma by the heat of the arc). Flux
wire does the same thing, but in a more localized and less effective
fashion. Generally, if I had my druthers, no matter what was being
welded, I'd prefer inert gas to fluxes, the byproducts of which are
often not good for one.
As for preventive measures, a scrub with warm water and a simple
detergent should remove enough of the remaining traces of brake cleaner
to make welding safe. In any event, the most serious cases almost
always have as a component lack of adequate ventilation, so it's always
safer to have some forced ventilation available. I did this even when
using tig on virgin metal, simply because the electrodes in use then had
small percentages of thorium added, the isotopes of which are all
radioactive. Since cadmium is toxic, the same would be true today for
tungsten-cadmium electrodes.
Cheers.
--
Michael Porter
Roswell, NM
Never let anyone drive you crazy when you know it's within walking distance....
_______________________________________________
Support Team.Net http://www.team.net/donate.html
6pack@autox.team.net
http://autox.team.net/mailman/listinfo/6pack
http://www.team.net/archive
|