Thread: Welding Duragal without grinding

Originally Posted by quercus

I am needing to make quite a few nursery benches out of 30 x 30 duragal RHS.

I was told I could just weld straight over the Duragal, since it was so thin.

I'm stick welding DuraGal RHS and angle at the moment. The coating might be thin but I still see wisps of zinc if I don't clean first so the fumes might be an issue. I'm cleaning near the joint with a flap disc which seems easy and effective.

quercus,
If your welding it properly you'll be burning through the gal and melting the steel like normal welding, just go for it...

I've welded more gal than I'd care to think of. I hate welding it without grinding for the fumes, the spatter, and the way it welds generally. But if there is heaps to do and its not structural (and you don't have an apprentice to grind ) you may as well just weld it. Try a little more voltage and a little less wire speed to help burn away the zinc. Try also a backwards-forwards action; ie, move forward quickly about 5 or 10mm and you will see the zinc burn off with a big blob of spatter flying off, then come back to a where the weld bead is (gal should already be burned off). It's hard to explain but once you try it you'll see what I mean. This is more a technique for hot dipped steel as it's a much thicker coating than duragal.

Anyway the worst thing about it is the fumes and I would highly recommend the use of a good P2 disposable respirator. 3M has a nice one with an outlet valve so you don't get too hot under it.

Good luck.

As well as the respirator, drink plenty of milk before, during and after welding zinc plating.

The fumes produced from welding on zinc are notorious for making the operator sick and the benefits of drinking milk are well documented.

Originally Posted by Woodwould

As well as the respirator, drink plenty of milk before, during and after welding zinc plating.

The fumes produced from welding on zinc are notorious for making the operator sick and the benefits of drinking milk are well documented.

Thanks for that

One Steel has a welding guide, which contradicts some of the conventional wisdom on welding galvanised steel: http://www.metaland.com.au/info/index.php?act=view&id=4

Might be worth a look. The zinc coat on Duragal is very thin. We didn't find it necessary to grind, but we were welding out in the open.

No doubt duragal is less fumy than hot dipped, but its still nasty to breath in the fumes. Especially in a closed shop with no fresh air circulation and welding all day. Anyone who has had the 'zinc shivers' knows what I'm talking about.

Originally Posted by Woodwould

As well as the respirator, drink plenty of milk before, during and after welding zinc plating.

The fumes produced from welding on zinc are notorious for making the operator sick and the benefits of drinking milk are well documented.

Hi all,


I do not agree at all with Wouldwould's statement re "well documented benefits of drinking milk"

If you mean milk to promote calcium build yes I'll agree,but as the oft repeated aid to prevention of flume fever,sorry no. Please clarify.

Having worked for Cyclone welding gates made from Gal pipe I was never offered milk to drink. Come to think of it no respirator either.Instead there was a vacuum tube which could not be placed too close as we used mig on the gate frames.

What I can recall was metal flume fever was a recurring symptom re-appearing stopping on Saturday on the Monday.Resistance to it it build up during the week and was lost when welding ceased.This is documented and not just a welders sickie ploy.

The symptoms were a flu type headache ,muscular pains , a sweet taste in the mouth and some times lots of vomiting.
Even then. I did not not believe a glass of milk was a preventive.Having spent an hour doing so,I I was not able to find any of well documented evidence on the net resources.
My belief is that the milk reference came from a 1940's war time welders bulletin from Lincoln who reccomended milk of magnesia as a suggested aid to the problem.

My assumption is that the Milk of magnesia was to absorb harmful metals which would them find their way out of the body by natural means.I think the milk of magnesia has corrupted into just plain milk by word of mouth and now has become little better than an old wives tale.

Some references I did find are here.

http://www.sperkoengineering.com/htm...Galvanized.pdf

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


If you aware of what is harmful in the area of welding generated fumes ,some of you would not want to weld.
If you have the slightest hint of asthma or bronchial problems ,the stuff is best avoided.

Cheers
Grahame

The time that it takes to grind all your tube for welding, certainly makes for a much cleaner, nicer job. I've welded trailers and gate frames in Duragal and it's a much nicer experience with the coating removed from the area to be welded.

I now have another job to do for a forum member in Duragal, and will definately be grinding before welding.

I have heard the most dangerous part of the fumes is the little whispy white floaty bit. Avoid breathing these in at all costs! (But you should be wearing a dust mask anyway.)

I'm surprised you haven't heard of the 'cure' before. It's as old as the hills (and definitely not an old wives' tale) and has worked for me on numerous occasions.

Google to the rescue again: http://www.google.com.au/search?hl=e...e+Search&meta==

I have welded the duragal metals to make cattle yards. I didn't worry about pre grinding. just welded it and worked well for me.

What I did have, was a fan blowing on me to blow fresh air, it worked well, even though it was outside.

Thanks for all that Guys, good food for thought. The link to the Duragal welding guide was especially good.
I too have read a fair bit lately about how Zinc fumes aren't as bad as first thought. Zinc oxide and zinc fumes it seems are good for you - like inhaling oysters.

I suspect the rest of the crap in the smoke is very very bad for you. I will be taking the conservative approach and using a disposable charcoal mask and setting up a fan - I can't afford fume extraction just yet.