Thread: TIG Welding Galvanized Steel

hey guys as some may know im building a trailer in my other thread im using a mix of galvanized and painted steel, i have read about grinding off the galvanizing which i plan on doing i will also be welding outdoors but the thing is i have been searching and searching the internet and so many people are saying the fumes are really bad for your health now i just found this web site

http://www.gaa.com.au/index.php?page=welding

scroll down to this bit

"Arc and oxyacetylene welding
In the arc welding or oxyacetylene welding of galvanized steel, provision must be made for control of welding fumes when planning procedures. Due to the relatively low melting point of zinc a proportion of the coating is volatilised and given off as a white zinc oxide fume. The presence of any fume evolved is obvious and this permits simple observation of the efficiency of the ventilation or extraction system. When welding is carried out in accordance with normal industrial practice with provision for adequate ventilation and air circulation, the non-toxic zinc fumes will cause no inconvenience. If adequate ventilation is not available, supplementary ventilation using air extraction equipment or forced air circulating equipment, should be provided. Although welding fumes from galvanized steel are not toxic, operators welding in a confined space should always be provided with suitable respirators to minimize possible discomfort. Fume development and consequent coating damage may often be minimized with certain joint designs in flat sheet by the use of copper chill bars. The chill bars are used as a backing strip or clamped on the weld side of the joint to absorb some of the heat generated during welding."

is this correct? so i wont harm myself welding this stuff? i have never tried welding gal steel so i dont know how much smoke is produced but ill need to be close while TIG welding it and i cant fit my respirator under the helmet, any ideas on which respirator i can use?

Fumes from welding Gal are extremely hazardous.

Suggest you read this and do a bit more research.

http://en.wikipedia.org/wiki/Metal_fume_fever

Highly recommend that you use Mig or Arc for Gal

Originally Posted by gazza2009au

hey guys as some may know im building a trailer in my other thread im using a mix of galvanized and painted steel, i have read about grinding off the galvanizing which i plan on doing i will also be welding outdoors but the thing is i have been searching and searching the internet and so many people are saying the fumes are really bad for your health now i just found this web site

http://www.gaa.com.au/index.php?page=welding

scroll down to this bit

"Arc and oxyacetylene welding
In the arc welding or oxyacetylene welding of galvanized steel, provision must be made for control of welding fumes when planning procedures. Due to the relatively low melting point of zinc a proportion of the coating is volatilised and given off as a white zinc oxide fume. The presence of any fume evolved is obvious and this permits simple observation of the efficiency of the ventilation or extraction system. When welding is carried out in accordance with normal industrial practice with provision for adequate ventilation and air circulation, the non-toxic zinc fumes will cause no inconvenience. If adequate ventilation is not available, supplementary ventilation using air extraction equipment or forced air circulating equipment, should be provided. Although welding fumes from galvanized steel are not toxic, operators welding in a confined space should always be provided with suitable respirators to minimize possible discomfort. Fume development and consequent coating damage may often be minimized with certain joint designs in flat sheet by the use of copper chill bars. The chill bars are used as a backing strip or clamped on the weld side of the joint to absorb some of the heat generated during welding."

is this correct? so i wont harm myself welding this stuff? i have never tried welding gal steel so i dont know how much smoke is produced but ill need to be close while TIG welding it and i cant fit my respirator under the helmet, any ideas on which respirator i can use?

LIKE HELL IT'S NOT TOXIC!!!!!
As Acco pointed out inhalation of Zinc fumes leads to metal fume fever. It is not pleasant at all. Trust me, I know this first hand.
The worst case I ever had was while welding up picnic table frames out of 50X25X1.6 galvanised RHS, 83 of them to be exact. All pre cut, a jig set up and away I went. Exposure time was well under 10 hours from memory. Having finished the job, I shut everything down and locked up the workshop. I was coughing by then, so much so that I actually vomited before I had gotten in my car. The drive home, roughly 45 minutes was an ordeal, as apart from coughing, I was shivering uncontrollably, despite having the heater turned full on and being dressed in combination overalls with jeans and shirt underneath. Unpleasant eh? The best was yet to come. I spent the entire night shivering in bed with the electric blanket on maximum while coughing my insides up, before going to work the next day still coughing a lot.
I am the first to admit that welding up 83 picnic tables in one hit in an enclosed workshop, (30MX18M with a 7M+ roof), will produce more fumes than welding a trailer frame outdoors, but Galvanised is most definitely toxic. Obviously the Galvaniser's Association has a vested interest in downplaying the risk.
What to do? Weld in a well ventilated area, use a fan if indoors. Try and stay upwind of the fumes. Use a respirator, particularly if you are asthmatic or prone to respiratory issues. You can buy respirators that will fit under your visor, both disposable and with replaceable filters that are designed for welding use. Clean shaven is the only way for a proper seal. Don't buy into the old wives tale of drinking milk to prevent metal fume fever - it's your lungs we worry about, not your stomach.
Grinding the galvanising off is only a partial fix as the internal galvanising is still present. I only grind off material that has been hot dipped as the coating is usually much thicker.
I understand that you like TIG welding due to your vision issues, but TIG absolutely hates galvanising and I think you will drive yourself crazy trying to weld galvanised product with it as you will be forever grinding contaminated tungstens. Mig or stick really are much better for galv.
I cannot stress that the fumes produced by many metals, lead, zinc, cadmium and bronze for example, are nasty and can lead to health problems that can kill you with long term exposure.

thanks Acco and Karl post much appreciated, what u have said is what i have read all over the internet including watching youtube videos, u make a good point about the gal contaminating the TIG weld karl i never took that into consideration but it makes clear sense i will have to MIG the job

do u know of any respirators that'll work? i see bunnings sell a disposable respirator for welding fumes but it says not suitable for coated steel so i assume galvanized steel

i went to my local welding supply shop they didnt have any respirators only those that cost a few thousand dollars, i than went to BOC and the guy tried selling me a whole box of disposables for $70-$80

Going from your Car Dolly thread, I take that you'll be welding outside? If so, a fan blowing from behind you is all you'll need, no need for a respirator mask.

Originally Posted by Acco

Going from your Car Dolly thread, I take that you'll be welding outside? If so, a fan blowing from behind you is all you'll need, no need for a respirator mask.

Acco is on the money.
It's all about exposure to a substance. Even water is toxic in large enough doses, but safe in smaller doses. So it is with welding fumes, (except lead and cadmium of course).
If you want to use a respirator due to underlying health issues or working to absolute best practice, then 3M make a twin filter respirator that uses soft filters rather than cartridges that will fit under a shield.
http://solutions.3m.com.au/wps/porta...4361846&rt=rud
Used with the appropriate filters.
http://solutions.3m.com.au/wps/porta...3696297&rt=rud
Or
http://solutions.3m.com.au/wps/porta...3696301&rt=rud
Alternately, there is a disposable model - only supplied in packs of 10 though.
http://solutions.3m.com.au/wps/porta...3686367&rt=rud

thanks guys, looking at the prices of those respirators ill go to BOC and pick up one from there, any ideas on where to position my self when welding the gal? i can only do horizontal welding so the trailer im building will need to be flipped in all sorts of positions to be welded and i will be standing over the top of the piece being welded and ill have to be close to see the weld too

Try and have the wind at your back where possible or across your body as second choice. Any air movement will certainly help.
While safety is always a priority, you aren't anywhere near the highest risk category in what you are doing as the total number of welds on your trailer would be unlikely to produce sufficient fumes in an outdoor environment to cause too much harm, unless you are hypersensitive for some reason. You will find those respirators do a fine job and are what I have personally used and will have applications outside your welding.
As much as any respirator can be, they are comfortable to wear into the bargain.

theres not much wind today because its raining in Sydney so if the showers ease up ill go cut and weld some offcuts of the galvanized stuff and set up a fan around 2-3 meters way on low blowing across the job and see how it goes one weld shouldn't hurt me much

Fans and ventilation and breezes outside will all conspire to make TIG welding more frustrating rather than easier. Add to that the amount of zinc that will blob onto your electrode and you'll soon discover that it won't be any fun at all trying to TIG it. The only way it will work is if you grind the gal off the surface, wipe it down and then do shallow, low penetration welds to make sure the zinc doesn't get drawn through from the back of the weld. Obviously you don't sub-standard low penetration welds on your trailer - so not really an option, except maybe for tacking up?

MIG or Stick is the go. Regarding MIG welding, weldingtipsandtricks has some good recent clips showing lack of penetration even on 'hot' MIG welds.

Regarding fumes - toxic or not, you don't want to breathe it anyway do you? Personally I've never had any issues with metal fume fever, but I do all the classic tricks - fans, weld near the outside door and when all else fails - hold my breath. I have got a respirator, but use it rarely, only when I'm in a confined spot that I can't avoid the fumes. There's a lot of riskier chemicals around and with some general awareness and simple avoidance measures, gal fumes aren't any more problematic than avoiding the normal fumes from stick, fluxcore, etc. IMHO of course

- Mick

A few other comments... I reckon facing side on to the wind is better. With the wind at your back, the air forms back eddies that tend to hold the fumes in the sheltered zone.

Although I don't use them much, those respirators that Karl linked are on the money - I've got a 3M half mask one (slightly different version) as well as the disposable. I'm sure I got the disposable ones at bunnings, although I couldn't find a link to the one recommended for welding one on their site. If you get the half mask - get the right size.

we have a slight breeze now so i welded side on the wind took most of the smoke away but half way thru the weld the smoke was incredibly thick coming in around my face i held my breath finished the weld than walked away

most defiantly getting the mask mentioned by 3M!!!!

not sure if this is penetration or just the zinc burning off?

Originally Posted by gazza2009au

we have a slight breeze now so i welded side on the wind took most of the smoke away but half way thru the weld the smoke was incredibly thick coming in around my face i held my breath finished the weld than walked away

most defiantly getting the mask mentioned by 3M!!!!

not sure if this is penetration or just the zinc burning off?

Galvanised is lovely stuff to weld isn't it.
I reckon that you are experiencing a combination of the gasless wire smoke and the fumes from the burning Zinc - either way, not good stuff to be breathing in. Some gasless wire is really smoky and in fact certain types are banned on some mine sites due to the fumes they produce, one type even having proven links to anal cancer I believe.
On the plus side, your welds are looking quite reasonable and seem to be burning through the galvanising and putting sufficient heat into the steel.
To my mind the answer is simple as to whether you should wear a respirator or not. You are noticing unacceptable levels of fumes and are both uncomfortable and unconfident, a clear case for protection if ever there was one.
Let us know how you go once you get a respirator.

i was only going to tack in place but ran a few welds, welding the larger lengths of steel didnt smoke nowhere near as much as the offcuts however down behind my shed got a little smokie so i walked away

at first i had my wire feed speed higher than the voltage which was just making really crap welds i than turned up the voltage and lowered the feed speed and i started getting what i consider good welds these were up hill welds scary at first but once i could see what was going on it was ok i had to slow down my gun movement to make sure the molten metal would fill in as i moved instead of leaving a blow hole after i done a few i got much better so tomorrow ill redo a few welds im not happy with, its all about gaining experience i guess and learning as i go

check out my other thread for updates http://www.woodworkforums.com/showthread.php?t=194406

Gazza, I TIG up galv most weekends. You just have to grind it clean, the same as you would any TIG job (i.e. mill scale, paint, rust). I never wear a mask, although I have a good mask for painting. I never get fumes except sometimes from the inside of tube a tiny bit, but nothing to contaminate the weld or for me to breathe in. A few pics from another thread:












Occasionally I don't clean well enough and as others have said - your tungstens will let you know about it straight away. I'm not a good enough welder not to flinch and jump when it pops and sputters. Luckily (or unluckily), the pop will be the zinc jumping onto your tungsten. There must be some sort of magic going on that makes it attracted to tungsten because that's always where it ends up. And then it's grind, grind, grind to clean and resharpen it. And invariably your job will be already tacked up or part welded so you have to put up with tungsten contamination for the rest of the weld. I'm not talking about continuing to weld full galvanised material - I'd throw that out and start again - I'm talking about cleaned galv that you didn't clean properly, which I may well try to weld out depending on the level of contamination. It only takes an invisible little bit to make it frustrating.

In that last picture you can see how close the galv was (from the right). It's within the HAZ and didn't burn.

Excuse the poor weld quality. There are reasons for it but it's good enough for the job at hand.

In the second pic if you look closely you can see some burnt zinc smoke. From the tack on the inside corner, right where the HAZ is, the little horizontal grey/white plume blown out from the inside of the tube.