Welding Galvanized Material

NCMau · Oct 8, 2011

I have a fair amount of galvanized 1/4" angle iron stock that I have been using for years in different projects (arc welding). I guess I am following safe procedures by always welding outside with fans blowing.
My question is: how much of the coating you have grind off for an effective weld?
Also I noticed if I heat the metal with the torch for bending, the coating pops. Should I also grind the area before heating? I suppose that would minimize splashing.

firedave19 · Oct 8, 2011

heating doesn't matter but should grind all coating off before welding and u should think of buying a respirator that smoke from galvanizing is really bad for ya

RoyJackson · Oct 8, 2011

If you get zinc poisoning (from the galvanized burning off...you'll have some difficultly breathing, IIRC), drink milk. That will alleviate it. You may want to go to the hospital...depends on how you feel.
However, grinding it off first is your best best (use a respirator for the dust). Grind about 2" or so from the weld joint. I doubt you'l be able to tell with your welding helmet on, but zinc burns with a green flame.

NCMau · Oct 9, 2011

firedave19 said:
heating doesn't matter but should grind all coating off before welding and u should think of buying a respirator that smoke from galvanizing is really bad for ya

Thanks. Respirator is a great additional precaution. I have one that I use for paint. Can I use the same one or should I get a different one.

jake98 · Oct 9, 2011

NCMau said:
Thanks. Respirator is a great additional precaution. I have one that I use for paint. Can I use the same one or should I get a different one.

Read the fine print, mine uses the same filter for both. I think you can weld right over the galv., just avoid the fumes. I'm not an authority on anything welding related tho.

RoyJackson · Oct 9, 2011

jake98 said:
Read the fine print, mine uses the same filter for both. I think you can weld right over the galv., just avoid the fumes. I'm not an authority on anything welding related tho.

You can weld or (in my experience) braze without grinding the galvanized coating....that's why I know the zinc burns green.
However, then you will get the fumes.

yomax4 · Oct 9, 2011

You can weld over the galvanised but it will be ugly, smokey and spattery. If you can't grind first, maybe use stick instead. Silicon Bronze is a faily good wire to use on galvanized or a gasless wire like NR211. The gases from the galvanized causes problems with the argon mix.

Short Game · Oct 9, 2011

Grinding the zinc produces both particulate and gasses. Hard to get a nice weld without grinding off the zinc. Easy to get a great braze, though. The zinc seems to make a great flux for bronze.

I don't like packing the respirator under my helmet, but it's worth it.

crash325 · Oct 9, 2011

Short Game said:
Grinding the zinc produces both particulate and gasses. Hard to get a nice weld without grinding off the zinc. Easy to get a great braze, though. The zinc seems to make a great flux for bronze.

Right on, zinc & brazing rod love each other.

Welding with stick or ? makes for a poor quality weld, usually week & pitted.

Fumes are poison, if you get enough that you can taste the zinc, drink lots & lots of milk. Work outside and wear a good mask.

Soundguy · Oct 9, 2011

I usually blow off with a torch then wire wheel, or grind off.. whatever I got handy..

that and weld outside with it / fan.. just try not to breathe welding fumes.. any of them.. zinc or not..

soundguy

Short Game · Oct 9, 2011

Soundguy said:
....try not to breathe welding fumes.. any of them.. zinc or not..

soundguy

Sometimes I just try not to breathe.

Shield Arc · Oct 9, 2011

I've welded literal tons of galvanized material. Multi-million dollar marine structures. Been poisoned at least a dozen times! Nothing fun about it, one miserable night, but OK the next day. Other than the lack of sleep!
Best thing I've found to weld galvanized material with is Hobart's Fabshield 21-B wire. Grind off the excess galvanizing, and have at it.

Soundguy · Oct 9, 2011

Short Game said:
Sometimes I just try not to breathe.

bingo!

soundguy

Tractor Seabee · Oct 9, 2011

Back in my younger pipefitter days we welded galvanized pipe a lot. Never ground off the zinc and never had a weld problem except the fumes. The zinc didn't into the root pass and burned off as you built up. We even gas welded smaller pipe. In fact the welded area maintains a lot of the galvanizing cororrison resistance. Fumes!! I breathed that suff so much that after 35 yrs I am still allergic to the stuff. Earlier, I got to the point I had to refuse to weld it even with respirator and sucker. Now that I am older, and I hope smarter, the medical aspects indicate do not do it, bolt it up or if you need the corrosion resistance make it up of bare steel first and send it out for galvanizing after fab. Once you cut or grind the zinc coating the rust will start any way unless you touch up the zinc coating. That spray can stuff only last as long as it takes to put it on. The hot process (that is how it goes on originally) is just as dangerous and requires a heating torch and a little know how. With the painting systems and powder coating available today galvanizing is probably on the way out. Enviornmental and OSHA rules have shut down a lot of the galvanizing shops and it has become a very expensive system.

grsthegreat · Oct 9, 2011

When i have to weld galv pipe, i wear my hobby air respirator unit. It draws fresh air from 50 feet away and the other side of my shop and pipes it thry a 3/4" hose to my 1/2 face mask. I also use it when plasma cuttiong and painting. There not too expensive and my lungs thank me. I modified mine with a 10 foot intake hose that is perminantly mounted outside my shop and has a hepa filter installed.

available online, ebay, etc http://www.clmcenterprises.com/

Soundguy · Oct 9, 2011

got a link to post for that kit?

chopped · Oct 9, 2011

here I think.
Hobby air, pro air, Fresh air respirator, SUPPLIED AIR RESPIRATOR, Axis, Citation, 3M, Bill Hirsch car care.

Short Game · Oct 10, 2011

Soundguy said:
bingo!

soundguy

Welded zinc and made green smoke. Never been sick. I might have turned blue though. I rolled with the punches, ducked the smoke.

If I've got a bunch of galv to grind or weld, I put on the mask.

Soundguy · Oct 10, 2011

chopped said:
here I think.
Hobby air, pro air, Fresh air respirator, SUPPLIED AIR RESPIRATOR, Axis, Citation, 3M, Bill Hirsch car care.

thanks for the link!

not a bad price for the half mask OR the hood.

I may pick one up for my shop.

I am planning to convert one of my garage bays into a paint bay, vs painting outside all the time.. if i do that.. I'll want supplied air..

looks like just the ticket..

soundguy

grsthegreat · Oct 10, 2011

Soundguy said:
thanks for the link!

not a bad price for the half mask OR the hood.

I may pick one up for my shop.

I am planning to convert one of my garage bays into a paint bay, vs painting outside all the time.. if i do that.. I'll want supplied air..

looks like just the ticket..

soundguy

They are a nice unit. I got mine on ebay for even less $$ than some stores sell them for. I especially like the clean fresh air while painting....cant stand to breath spray fumes.