Remove Galvanization

Galvanization is the process in which steel or another metal is coated in zinc to stop the base metal from oxidizing. In this instructable I will tell how to remove this coating of zinc. Some people may be wondering why you would want to do this. Well, when galvanized metal is welded it gives off toxic fumes that can be harmful.

(NOTE: I apologize for the poor image quality)

Step 1: Supplies

for this instructable you will need:

vinegar

a wire brush

a small glass bowl

a small flashlight (optional) 

Step 2: Soak It

First, fill your bowl with vinegar, then put in the piece of metal from which you want to remove the zinc. Its that simple. It took about half an hour to remove the zinc from a screw about 4 cm. After a short period of time bubbles should appear on the surface of the vinegar and there should be small semitransparent lumps that come off the piece of metal. I used a glass bowl so I could shine the flashlight through the vinegar  to see the bubbles and the lumps better, but this is optional.

Step 3: Brush It

After the half hour has passed, take out the piece of no-longer-galvanized metal. Once you take it out, rinse it under cool water and scrape it with your wire brush. After you have brushed all over the metal, rinse it off again and its safe to weld it.

NOTE: Because screws have threads I would not recommend using them, they take longer than rods or another shape that doesn't have threads.

Comments

[RobertN201]

I have a 2ft long chain that I want to strip the zinc off of by putting it in a bowl of distilled white vinegar outside overnight. That way I can use the chain to hang a pot over my fire so that I can cook 2 things at the same time outside and without the chain burning off zinc into my food. But where do I dump the zinc sludge? In the grass anywhere?

EDIT: Ok I just started the process. I coiled up the chain and put it in a clean recycled tin can, filled it up with vinegar over at my greenhouse to sit there over night. I'll let you all know how it goes and I'll keep this post up to date throughout the process. I have a brass wire brush and more vinegar if I need to change it out a few times.

EDIT: It's been 24 hours. The surface of the vinegar was frothy so it looks like it's been doing something in chemical reaction. I dumped the vinegar in the snow. The chain looks less bluish, I refilled the can with vinegar and gonna leave it sit for another 24 hrs. Then I'll spread it out and wire brush it tomorrow.

EDIT: Ok. I dumped out the vinegar. The chain looked like a dull bluish color. I then lightly rinsed off the chain with a bit of vinegar and spent about 15 minutes with the wire brush very thoroughly scraping each chain link. Then I took it inside to rinse it off with some water and I noticed the whole chain turning brass color the same color as my wire brush. What the heck lol. Anyways. I dried the chain off with a paper towel and set it by the heater to dry. Later I will put it in the fire pit just to make sure that any remaining zinc burns off. Actually, I think I will rinse it in vinegar again to get the brass crap of first before burn. In conclusion: if you use a wire brush, maybe its better to not use brass wire brush.

I soaked the chain in vinegar to get the brass crap off, that didn't work. Isopropyl worked a little better. Then I put the chain in the fire. The fire burned off the brass crap. I pretty sure I got all the brass and zinc off of it now. Don't use a brass wirebrush. Maybe the copper or steel.

[Robby Lombardo]

Rookie hobbyist here. I'm trying to strip the galv layer from a couple nipples of threaded steel pipe I got at Home Depot.

Does this only corrode and strip the zinc layer or is there a danger of rusting the iron as well if I leave them in too long? It's vitally important that I'm left with a level and unpitted iron pipe.

[dancmarsh]

I find that after any kind of chemical treatment, steel will "flash" rust. A layer of oil or weld through primer may be a good idea. Rust won't occur until it hits the oxygen in the air though.

[killerjackalope]

Surely not buying galvanized screws would be less effort ;-p good idea though...

[tranoxx]

well yes but i dont have access to ugalvanized screws or bar

[anvil_man]

check the phone book or look for weld shops we use bare steel all the time.
unplated screws are hard to find but you can if you look.

[KristjanM2]

its just an exempel of a galvanized object it culd reley be eney thing that isnt Fire galvanised

[Dr Qui]

I find that statement extremely hard to believe.

[Craftsmanhux]

How can you tell that all galv is off 100%

[OisinL1]

How do I dispose of the residue? I'm using HCl and baking soda to neutralise. Where can I dump to solution that is left over?

This does work really quickly though and the foam is easy to remove.

[Frosttoys]

Vinegar is acetic acid, all you need is baking soda and its neutralized

[solarbipolar]

If you've been welding for 12 years, you should have known that welding zinc is harmful. It isn't the responsibility of your employer to educate you.

[Frosttoys]

Its 60000000000000 times the responsibility of your employer to educate you of the hazards on the job, its actually a massive liability because if you werent trained or made aware by signage or anything they can actually be sued for such a failure.

[VictoresNox]

will running a piece through a dryer w/ no heat in a bag of sand clean it off?

[blhack]

This so awesome! I always end up just grinding the surface off. Thank you so much!

[RichardW5]

Awesome info. Thanks

[aeray]

Hydrochloric acid (muriatic acid, available at hardware stores) works well too. And very quickly.

[tranoxx]

it probably does but this is cheap and can be done with supplies found around the house

[aeray]

Hydrochloric makes NASTY fumes too, so I'm sure your method is safer as well.

[bombmaker2]

In addition to those fumes, it also makes hydrogen gas. Dangerous, but fun.