Can galvanized pipe (fence posts) be MIG welded?

Galvanized metal is MIG welded all the time. Just keep your head out of the fumes. The zinc in the fumes will give you fume fever. It is seldom serious but will make you wish you were dead for a while. You can mechanically or chemically remove the zinc before welding if you want to eliminate the possibility of exposure.

Thanks for the reply. Any idea what chemical(s) would be required. I kinda like my health and would rather take some type of precautions. Thanks Duane

Muriatic acid will remove the zinc. Ofcourse, then you have to neutralize the acid, wash off the part, and let it dry. Most folks who remove it just grind it off. You could wear an appropriate respirator, properly fitted, if you don't want to bother removing the zinc before welding and are concerned about breathing the fumes. They are pretty cheap. I just pay attention to which way the fumes are going and keep my head out of them. Never had a problem. If you do this and get white dust (zinc oxide, the same stuff used in some sun screens) in your helmet, your head is in the wrong place.

I'm not an expert, but I have heard this repeatedly, working in the metals industry... Zinc poisoning is temporary. That means the body must be getting rid of it over time. Reputedly, "zinc sweats" last for a few days. Many metals, particularly the rare ones, are both toxic and cumulative. That means they build up in the body and more ingestion adds to what is there. That is serious. It means tiny dosages are not acceptable. With zinc, people are quite cheerful about it, because the body metabolises zinc (it's a necessary nutrient, though in small quantities). That is why folk who have been around a long time can say things like "hold your head out of hte fume" - because they are still alive and well to say that! Doesn't the arc turn sort of lilac coloured if you are getting a lot of zinc in it? It's been a few years since I've met that. I got *&*((%&(* annoyed with an employer whose stock-room was full of bits of galvanised steel - all that was left - and they wouldn't get a few dollars of new steel.

Richard Smith

In my 'backyard' welding experience I have welded galvanised schedule 40 pipe several times and for one project tack welded some sheet. I stick welded the pipe outside. With the pipe I ground off the coating for a couple of inches past my estimated HAZ. I welded with the breeze behind my back and, for extra caution, held my breath during the welds. On completing each bead, I stepped back away from the drifting smoke and let it clear before going back to look at my handiwork. Of note is that the inside of pipe is coated too and, of course, grinding with a disk only gets the outside stuff off so I still had a lot of coating to contend with during the welding of the pipe.

For the sheet, I ground off both surfaces and TIG welded the sheet to some uncoated steel angle. That worked okay but the HAZ was a little greater than I estimated and I saw some of the characteristic white smoke produced by the burning galvanised coating. Again, this welding was done outside with the breeze moving any fumes away from me.

Initially I was very fearful but with the experience--controlling against breathing fumes--I am no longer vexed by the prospect of welding the stuff in the situations I have had so far.

When you weld galvanized you have the zinc fumes issues that others mentioned. You also need to deal with zinc contamination of the weld area. If you are stick welding with an agressive rod like 6011 AND have a solid bead going, the arc force will burn off the zinc in front of the weld. Gives you a solid weld. Using MIG with less penetration, pipe joints with poor fitup, and out of position welds (tough not to have at least some with pipe) will all contribute to penetration and weld joint fusion problems. Not a project killer but anything structural or safety related needs special attention

I deal with galvanzied by dipping the end of the pipe in 1" of muriatic acid (hydrochloric acid)for a couple of minutes. Rinse throughly, dip in a solution of dishwasher soap, rinse again. Gives a nice 1" section with no zinc inside or out. 30% HCL is stocked in swiming pool supplies at the local home store, $2 a gallon.

69Rocketman wrote:

Also know as Hydrochloric Acid around the high school lab. It just takes a few seconds to remove the Zinc but be prepared for instant rust on the pipe.

Howdy! Now, not to argue, but it was my understanding that the fumes created when welding zinc plated steels, were no longer truly zinc. I had read a few times I believe where it changes into poisonous noxious gas, somewhat similar to the first generations of the first world war poisons. I know for a fact zinc is very very reactive, and most everything very very reactive, is horrible for the body... except O2 :P I have successfully welded galvanized fence post pipe though. It's kind of a steel, but I think it's very pot metal like in make up. Perhaps an electrode choice for difficult to weld, or unknown steels would be the correct choice. No matter what or how you go about it, I would not think of welding with the zinc still on the pipe. I allways sanded it off first. It's very light, pretty fast work. Good luck on your projects!! Brian Lee Sparkeee24

Some of the tubing (auto exhaust pipe) has a light alumized finish that give reasonable corrosion protection, burns off easily when welding. What remains in the weld joint is on the same order as what you get in AK (aluminum killed) steel. Other tube (electrical conduit) still uses zinc but MUCH lighter coat. Fence materials can be all over the map with zinc thickness. Cheap stuff has very little, expensive stuff just drips with it. The corrosion protection life expectancy is directly related to the thickness.

There was a lot of use of cadminum in the 50's and 60's, VERY toxic stuff. Pretty much banned right now.

Sparkeee24 wrote: