[6pack] brake cleaner and welding warning

[Michael Porter]

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....