stripping zinc with vinegar

[dilbert firestorm]

someone told me that I can strip zinc in a plastic tub filled with vinegar?

I know vinegar has lots of uses, but is this so?

[Jon Danniken]

Dunno about vinegar, but good old muriatic acid takes it off pretty quickly. You do need safety gear for this, though.

Jon

[Colbyt]

Why do you want to strip it?

If it is just so paint will stick and not peel, a full cycle through the dishwasher or soaking in a pan with hot water and dish machine soap will do the job.

Colbyt

[dilbert firestorm]

what does the dishwashing process do to it?

[Colbyt]

The stronger dish machine soap along with the hot water removes all oils left over from the manufacture. It also tends to dull the surface so that paints sticks as well as paint can stick.

The process is about the same as a years exposure to the elements which is about how long you wait if you want paint on metal flashings to adhere well.

Colbyt

[DT]

Oh, it will just fine. I built some structures this past year using Unistrut for parts of them, and needed to strip the ends for welding. Vinegar strips the zinc plated ones overnight, and the galvanized ones take a day or so.

[dilbert firestorm]

I think David gets it after I showed him the white vinegar link. :)

[dilbert firestorm]

which is why I'm not messing with that nasty stuff. As nasty as this stuff is, its amazing how much damage its corrosive fumes can do.

[Jon Danniken]

Well obviously you don't want to breathe in the vapors, or get it on your skin. I do it outside, and stay upwind. Chemical gloves, a mechanics suit, safety googles and a face shield are necessary, and make sure you are not near an open flame. Have a box of baking soda nearby for spills and cleanup.

I put the part to be de-galvanized into a plastic container, and use a chip brush to apply the acid.

As the procedure continues, you will need to add more acid, as you end up converting the Zn into a ZnCl solution, and releasing H2.

Like most things, once you have the setup it is a relatively simple prodecure, and kind of fun.

Jon

[dilbert firestorm]

thanx for the explanation for the dish-washing technique

[dilbert firestorm]

do you how baking soda figure into white vinegar? I've seen comments where they say after the zinc is stripped from the metal, neutralize it with baking soda and wash it in soapy water and rinse it in fresh water & dry. whats not clear from the comments were, are they neutralizing the vinegar acid or the metal or both.

[Bob Villa]

I remember this from the by-gone days. It was referred to as "pickling" to allow the paint to stick to galvanized gutters.

[Jon Danniken]

Take a teaspoon of vinegar and sprinkle some baking soda into it. What happens? What happens when you keep adding baking soda?

Jon

[dilbert firestorm]

you can make a faux volcano out of this stuff. it just foams over almost like lava.

however, I'm not sure what happens if you keep adding baking soda to the mix.