Thread: best welder for Gal?

Originally Posted by Danger Mouse

Is there a preference for mig or arc with gal coated mild steel? In continuing to try and identify the best welder for my needs I am trying to see if I am better with an inverter stick or a mig or a combo unit. I think I will be welding a bit of gal so hence the question.

Still like the look of the weldmaster 182p and the cigweld 175i as far as the combo units go.

Stick burns through gal better than mig. you're better off grinding the gal off before doing any welding. I prefer to use a stick on gal so I can set up a fan to blow away the fumes. (highly toxic) I've been told that drinking milk before welding gal or doing hard-facing will lessen the effect of the fumes. I guess the idea is that it puts a lining on the throat and stomach. I welded tabs to about 20 gal posts quite a few years ago, I can still remember the tinny taste in my mouth and throat as I was spewing up white froth. Please take a bit of advice from an old-timer, grind as much of the gal off as you can, have a fan or extraction fan running whenever you grind or weld the stuff, it is poison. I couldn't smell the fumes while I was welding so please be careful.

Originally Posted by Danger Mouse

Is there a preference for mig or arc with gal coated mild steel? In continuing to try and identify the best welder for my needs I am trying to see if I am better with an inverter stick or a mig or a combo unit. I think I will be welding a bit of gal so hence the question.

Still like the look of the weldmaster 182p and the cigweld 175i as far as the combo units go.

Inreality it's better to just grind the gal off before u weld. In my experience I believe that the mig is alot easier to weld with. Depending on how much and what u weld in regards to weather your better off with gas or gas less.

And some coatings also contain Cadmium, which is up there with Arsenic & Lead as a cumulative poison.

So, grind the 'Gal.' off before welding, do it outside in a breeze if possible or wear a decent mask with a filter rated for metal/welding fumes. You won't be able to reach any coating on the inside of tubing & it seems to catch fire fairly regularly, and the oxide deposit affects welds too.

Originally Posted by bsrlee

And some coatings also contain Cadmium, which is up there with Arsenic & Lead as a cumulative poison.

So, grind the 'Gal.' off before welding, do it outside in a breeze if possible or wear a decent mask with a filter rated for metal/welding fumes. You won't be able to reach any coating on the inside of tubing & it seems to catch fire fairly regularly, and the oxide deposit affects welds too.

If it's Aussie galv then if it was galv after about 1980 it should have safe amounts of Cd. The Zn Oxide is breathtaking enough and as others have said get yourself a fan to disperse the fumes.

I agree with all here, grind as much as practical off and even then well ventilated and if using a fan or breeze present, stick is the way to go. I have been poisoned, breathing fumes when oxy cutting galv plate steel when I knew no better as an apprentice, and mind you I was under instruction from a tradesman at the time. I was off work for three days and very ill.
So yeah it's not good to ever breath in welding fumes of any kind and especially any plating.

Probably 80% of what I weld is Duragal sections with my UniMIG 165 both with MIG and stick depending on convenience (and thickness). I use CO2 shielding gas for MIG, and I'm told this does burn through gal better than the more common Argon/CO2 mix.

Duragal, being a continuosly-galvanised product, has a much thinner layer of gal than batch-galvanised steel, and I never bother grinding it first, but it does produce a lot of fumes, so forced ventilation, or working outside is a must. For batch stuff, you really do need to grind away the gal.

First of all, let's get rid of the hideous old wives tale of drinking milk to lessen the effects of breathing galv fumes.

IT DOES NOTHING!

The breathing of metal fumes such as those produced by galvanising causes what is known as Metal Fume Fever, it is similar to a chemically induced flu in its symptoms - shortness of breath, cold flushes and much coughing, even to the extent that you will vomit as a result of all the coughing. It is serious and not to be taken lightly. As has already been said it can put you in hospital, not to mention the carcinogenic effects, remember the old saying "you never see an old boilermaker".
What to do? Ventilation, preferably from behind to take the fumes away from your breathing area, PPE such as a proper mask, (no, a paper dust mask will not do) or if you can justify it a welding shield with an inbuilt air supply.
Realistically most home handymen will not weld sufficient quantities to create a serious smoke screen in the shed if the simple precaution of ventilation is observed however those with asthmatic tendencies need to be more vigilant.
Zinc is not the only common metal that produces such fumes, aluminium will produce large volumes of fumes also as will bronze. In my experience self shielded flux core wire is also very fumey. Just another reason I hate the stuff with a passion!
As far as welding coated steel, stick will do a very good job, remembering that many coated sections are sub 2.5mm which can challenge some operators. Remembeer though, the fumes are still there from the burning galv. If using a mig, there is one stand out gas for galv steel, (most steel using short arc in fact), CO2. The advantages of CO2 are less spatter when welding galv, less porosity and better penetration of the galv as well as superior mechanical properties in many areas, plus it is much cheaper to use.
Personally, I would never grind the galv off unless it was a hot dipped component with its far thicker coating, in fact the manufacturers of Duragal say that no special allowances need to be made when welding their product, which is not a true galvanising anyway, being only on the outside of the section. Generally the polymer coating used to protect the thin zinc layer on duragal gives more trouble than the actual zinc does. I would however choose a well ventilated area and if doing continuous work, wear a mask designed to protect against metal fumes.
As an added caution, much of the cheap galv steel sold may be sourced from China and some has been found to contain lead which is even worse to inhale.
I believe your choice of welder comes down to your welding environment - outdoors or indoors, material thicknesses, >1.6mm or <1.6mm and your usage level. For mr/s average there are few circumstances that cannot be handled by a good inverter stick welder if they learn how to use it properly.
Inverter sticks are still the weapon of choice in most industrial maintenance scenarios.
If I could have only one welder, it would be a good inverter stick, with it I would be equipped to handle mild steel, galv steel, high tensile steel, stainless steel, weathering steel, cast iron, bronze, hard facing even aluminium (albeit in heavier sections, say 4mm+) plus I could even set it up to DC tig weld.
Pretty handy little device eh?

^^^^^^^^What he said!

Gal ain't gal!

Heavy zinc coatings where the object has been dipped in liquid zinc present the most issues if they have to be welded you need to grind off the zinc. Arc is much less sensitive compared to MIG depending on the amount of gal. You will know straight away if there is too much gal as the MIG weld will have porosity clearly visible. This can vary depending on how much current is used to weld too.

Other galvanised coating that have been electroplated on in may cases are relatively thin and require no special preparation. For example the thin Zinc Anneal steels and Duragal all have coatings that have welding in mind in particular MIG welding. They are still a little bit sensitive in my experience with welding current and I tend to run a little hotter when welding Duragal. But otherwise there is no need remove the coating on these thin coated materials.

The only exception to this is if you are welding small tack welds onto these types of steel, if the tack weld is not quite hot enough you won't properly burn through the coating so its often better to grind a small section to bare steel and start the weld from there.

Ventilation is the key to welding anything with a zinc coating in terms of OH&S.

Cheers

Justin

Great feeback guys - thanks to all!

Originally Posted by Karl Robbers

First of all, let's get rid of the hideous old wives tale of drinking milk to lessen the effects of breathing galv fumes.

I believe the myth came about from the (probably also mistaken) belief that you could drink "milk of magnesia" (not "milk of cow") to reduce the body's uptake of zinc with exposure to gal welding fumes. I probably picked that up from this very forum.

Originally Posted by Karl Robbers

If I could have only one welder, it would be a good inverter stick

Particularly if you rig it up as a TIG