I didn't know where to put this so I'll put it here.

We folks that weld often put heat to metal without thinking about what we've been cleaning with. Brake cleaner is in my shop, so is carb cleaner, and other solvents. Here's a guy who got badly injured by a little puff of gas that was generated when he was mig welding. Didn't know this, so I'm telling everyone I know. It's pretty chilling!

http://www.brewracingframes.com/id75.htm

It has been posted before (the article was from 2009), but it is good information to share again.

hard to find brake cleaner with chlorine nowadays.

Wow, thanks for posting that!

Being a new welder, I could see myself making that mistake very easily. You may have just saved my life...

Thank you from my wife, 11 month old daughter and myself...

AL

I don't weld, but I know a couple of young welders I will pass this info onto. Good stuff to know!

quote hard to find brake cleaner with chlorine nowadays.

So is it chlorine that causes the gas? Not brake cleaners w/o chlorine?

[This message has been edited by 1fatcat (edited 02-14-2011).]

Edited: Using brake clean or other chlorinated cleaners prior to welding or other process that generates excessive heat should be avoided.

[This message has been edited by fieroguru (edited 02-16-2011).]

quote Originally posted by fieroguru: The issue is exposing Tetrachloroethylene (from the brake clean) to Argon at elevated temperatures (like welding). Argon is one of the more common gasses for mig/tig welding ...

Argon doesn't have anything to do with it. In fact, Argon is an inert gas ... which means that it doesn't react chemically with anything. That's why inert gases like Argon and Helium are used as shielding gases for some types of welding.

The problem is chlorinated hydrocarbons decomposing upon exposure to intense heat and/or ultraviolet radiation of welding. Phosgene can even be formed when chlorinated hydrocarbon vapor is entrained into an open flame, as from a propane or acetylene torch. Even when inhaled in small quantities, Phosgene gas can irreversibly damage sensitive lung tissue.


Edit: to remove references to incorrect information since deleted

quote Originally posted by 1fatcat: So is it chlorine that causes the gas? Not brake cleaners w/o chlorine?

No Chlorine => no Phosgene.

That said, any hydrocarbon solvent can form hundreds of compounds when exposed to the heat of welding, and some of them may be harmful if inhaled. Parts should always be dry of solvents before welding. Good ventilation is a must. Welding under an exhaust hood is recommended whenever possible, and it's often required by law in an industrial or commercial setting.

[This message has been edited by Marvin McInnis (edited 02-16-2011).]

quote Originally posted by Marvin McInnis: Argon doesn't have anything to do with it. In fact, Argon is an inert gas ... which means that it doesn't react chemically with anything. That's why inert gases like Argon and Helium are used as shielding gases for some types of welding.

Take it up with the author of the article:
"The active chemical in the brake cleaner is tetrachloroethylene. When this chemical is exposed to excessive heat and the gas argon, which is used in MIG and TIG welding, it produces phosgene."

quote Originally posted by fieroguru: Take it up with the author of the article ...

Indeed. The only references to argon participating in the formation of phosgene that I can find in an Internet search all trace back to the biker magazine article originally cited above. As best I can tell, the argon myth started with that article. I stand by my statement: Argon is an inert gas ... which means that it doesn't react chemically with anything. Anyone who passed high school chemistry should know that. And as far as I can find, argon cannot act as a catalyst for other reactions either. Just because argon is present DOES NOT mean that it plays any part in the phosgene-generating reaction.

For a more scientific investigation of the dangers of phosgene due to welding, see this link. Note that this report was written in 1971.

The most important thing to know is that Phosgene can be generated by heating chlorinated hydrocarbon solvents while brazing or welding, gas or electric, whether Argon is present or not. Just because you're not using Argon doesn't mean you're safe.


Edit: to remove references to incorrect information since deleted

[This message has been edited by Marvin McInnis (edited 02-16-2011).]

The reason the Argon helps is it prevents oxidation of the brake-clean while the chemicals form. It doesn't react itself, just prevents the brake-clean from burning (oxidizing).

quote Originally posted by aaronkoch: The reason the Argon helps is it prevents oxidation of the brake-clean while the chemicals form. It doesn't react itself, just prevents the brake-clean from burning (oxidizing).

Phosgene will form with equal efficiency whether argon is present or absent.

[This message has been edited by Marvin McInnis (edited 02-15-2011).]

Does it really matter how it forms!

Avoid using the cleaner when welding (.)

[This message has been edited by ALJR (edited 02-15-2011).]

quote Originally posted by ALJR: Does it really matter how it forms!

Yes it matters, when there are people who mistakenly believe that chlorinated solvents are safe as long as Argon isn't present, as when you're welding with flux-core wire or using CO₂ as the shielding gas. Misinformation like that can kill or injure people.

quote Avoid using the cleaner when welding (.)

I agree. Avoid chlorinated solvents when welding or around open flames, under all circumstances.


Edit: to remove references to incorrect information since deleted

[This message has been edited by Marvin McInnis (edited 02-16-2011).]

https://www.fiero.nl/forum/F...1/HTML/084456-2.html

I revised my post to remove the inaccurate information. But it is still present in the thread because it was quoted...

[This message has been edited by fieroguru (edited 02-16-2011).]

quote Originally posted by fieroguru: I revised my post to remove the inaccurate information.

My sincere thanks for doing that. I have also edited my posts to remove references to that information.


FWIW, I consulted with an old friend who is a chemical engineer, recently retired after a career as a high-level chemist and plant manager in the pharmaceutical industry. Here are his comments:

"My first thought was that this was absurd since argon is normally considered chemically inert.
...
I looked at a few industrial safety websites and found no mention of argon being involved in such a reaction.
...
I looked into this a little more and I am convinced that the argon part is complete bullshit. I think ["Brew Dude"] read that phosgene could be formed from TCE while arc welding with argon and mistook that to mean the argon was involved. According to one source [synthesis of Phosgene] can take place at relatively low temperatures, certainly attained even with gas welding."

[This message has been edited by Marvin McInnis (edited 02-17-2011).]