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Welding question

Bluedog225

Texas
Joined
Nov 18, 2019
Messages
2,830
I’m going to build a single pole mount using rigid metal conduit 4” base, a cap fixture, and 2” cross member.

I’ll have double strut on the cross member held in place with U-bolts.

I’d like to tack weld or braze the U bolts in place to prevent the strut from rotating except in union with the 2” pipe.

Can I weld or braze hot dipped galvanized? I know it‘s not great health wise, but I just need a little tack to hold the U bolt in place.

I‘ve got a brazing rig and can get someone out to weld.

I figured we had some welders here who would know.

Thanks in advance.
 
I TIG welded some of the ground mount, all the pipe was hot dip galvanized.
The galvanize won't weld, and as you point out, is dangerous (lethal fumes)
So I used a grinder and removed the galvanize where I was going to weld.
Need pure, clean steel for the weld to work.
Grinding does not remove all the galvanize, so weld outside, upwind, so the fumes move away from you.
(Or use a big fan)
After I was all done, painted the weld with "cold galvanize" compound, worked great!
 
Firmly bolting down the U bolt should prevent any rotation.
 
I've successfully welded galvanized. Keep a carton of milk handy in the frig, because Calcium is the antidote for Zinc poisoning.

Give very careful attention to your ventilation. You can see the Zinc vapor floating in the air. I've welded 8 full-size solar array frames now, and I haven't gotten any Zinc toxicity yet. Keep it ventilated and you'll be fine.

When you do the welding, keep in mind you'll need to keep your bead focused on the welding site a little longer than plain steel. You first have to evaporate off the Zinc before you get down to the solid steel. Try to weld too fast, and you will be just soldering.
 
Just have good ventilation. I got zinc oxide poisoning from welding galvanized pipe in garage when I was about 15 years old, young, dumb, and invincible.

Felt like I had the flu that evening but I was okay by the next morning. I don't believe I have gotten a cold or flu in 50+ years since so must have stocked up on zinc for a lifetime.
 
Can I weld or braze hot dipped galvanized? I know it‘s not great health wise, but I just need a little tack to hold the U bolt in place.
You can weld the steel under the zinc, you can not weld ontop of the zinc. It will effectivly burn off the zinc and weld the steel ubolt to the steel pipe. you will need to paint the weld to keep it from rusting.
 
It will effectivly burn off the zinc and weld the steel ubolt to the steel pipe. you will need to paint the weld to keep it from rusting.
Yes, that was what I did. The arrays look quite sharp painted in bright white! Pay attention though to the proper cleaning instructions for painting over galvanized steel. Hot, soapy water works very well for surface prep.
 
If you're welding galvanized steel outdoors the worst you can expect is a runny nose unless you're welding with your nose a couple of inches from the work. I usually use an angle grinder to remove the zinc from the work surfaces not because of fear of poisoning but for faster, easier welds on box section steel.
 
I’m going to build a single pole mount using rigid metal conduit 4” base, a cap fixture, and 2” cross member.

I’ll have double strut on the cross member held in place with U-bolts.

I’d like to tack weld or braze the U bolts in place to prevent the strut from rotating except in union with the 2” pipe.

Can I weld or braze hot dipped galvanized? I know it‘s not great health wise, but I just need a little tack to hold the U bolt in place.

I‘ve got a brazing rig and can get someone out to weld.

I figured we had some welders here who would know.

Thanks in advance.
Just weld a tab with a hole in it to the u bolt, then drill and tap to locate the u bolt when assembly is complete
 
You need to strip the galvanization off first or it will weaken the weld and produce poisonous gasses.

Use Hydrochloric Acid (Muriatic Pool Acid) to strip the galvanization off the spot you want to weld.

If its a round pipe, I would use plastic packing tape (the kind they use to close boxes for mailing) to tape off the areas you want to save and turn the pipe horizontal.. Then use a nylon brush to coat the steel with acid and water to wash away. You'll probably have to repeat the process several times and wait in between coats. Be careful, hydrochloric acid is pretty darn nasty. It will eat a hole right through your driveway so all the drippings need to go into something plastic. And if you get it on your clothes, goodbye clothes..

Once the acid has done its job, rinse the area really well with water, then use a wire brush to clean it up and maybe one more rinse. Once done, get some naval jelly (phosphoric acid) and coat the steel with it for 20 minutes. Since you used water to wash the hydrochloric acid away, the steel will begin to rust a bit.. you need to stop that process now or it will never stop. The phosphoric acid will convert any iron oxide into iron phosphate which will protect the steel from rusting again. The steel will turn dark gray after the phosphate treatment.

Now you can weld.

Once done welding, hit it with the phosphoric acid again, rinse with water, immediate dry the area, and use a can of "cold galvanizing compound" to spray everything with two coats.

You can paint on top of that if you want.
 
Muriatic acid can be found at any masonry supply. It’s what we use to clean trowels.
We just spray em with wd40 after though. Not sure about any jelly lol ?
 
the simplest and easiest way to weld galvanized stuff is to reverse your polarity, simply plug your stinger into the ground and your ground into the positive. it works because as you weld it blows the zinc out. this will not work with migs and tigs only stick welders.
 
I myself have not found this to be necessary. Every frame I've welded (8 now) had been galvanized, and once you learn the idiosyncrasies of galvanized, it's very straightforward. You just keep the bead focused on your welding area a bit longer to boil off the zinc, and you make sure you have good ventilation. Since I only weld outside, zinc exposure has never been an issue. Stop worrying and just get it done.
 
I myself have not found this to be necessary. Every frame I've welded (8 now) had been galvanized, and once you learn the idiosyncrasies of galvanized, it's very straightforward. You just keep the bead focused on your welding area a bit longer to boil off the zinc, and you make sure you have good ventilation. Since I only weld outside, zinc exposure has never been an issue. Stop worrying and just get it done.
Like your style, perfect answer. I do the same.
 
I wouldn't be concerned with zinc poisoning outside in the wind and only tack welding. Especially if somebody else is doing the welding! :cool:
 
I made some minor repairs to a galvanized gate and did not find it tricky in the least, other than the usual 'its thin metal' stuff. I sprayed 'cold galvanizing' "paint" over it and it looks fine some months later.
 
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