post weld cleaning of stainless

I'd guess sodium carbonate. Google groups for "electrolytic rust"

There is a citric-acid based system called CitriSurf. Google for their website. I've done small jobs with a home-brew of 10% food-grade citric acid and 1% sodium EDTA dissolved in distilled water. Basically the same stuff as the CitriSurf, except theirs includes additives to make the solution gell some, so it doesn't run off vertical surfaces.

Warm the solution and use it to electrostrip at about 18-20 volts. Works like a charm. Wand is a piece of copper tubing, flattened at the end with a piece of green 3M cloth wire-tied around it. Rest of the wand is covered with heat shrink to insulate it. The work is positive polarity, so the ions come off the work, wand is negative.

The EDTA is a chelating agent that helps keep the stripped metal in solution. =20

Regards,

Bob

I use Citrisurf 2050 regularly. Does a good job of cleaning up discoloration. If I need really heavy cleaning before polishing I soup it up some in a 5 gallon plastic bucket with a stainless anode and a DC power supply. About an amp/sq. ft. for 10 minutes or so gets it ready for a first class polishing. With a little DC help it will also eat off enough weld bead to expose any inclusions too which can be good or bad for a gorilla welder like me. :-)

My procedure is to soak in the bath for 10-15 minutes to remove the weld stains then polish with emory on a sisal wheel to remove machining marks. Then hook up the DC power and adjust the voltage to get about 1A/sq.ft. and soak it another 10 minutes to remove the polish smears. Next a spiral wheel with stainless compound and a final polish on a loose wheel loaded with white rouge for color makes a gleaming finish.

I have sent stuff off to be professionally electropolished and my DIY finish looks better.

Isn't that a form of electropolishing?

John

Last thing first- These are portable electropolishers.

All they are is a transformer- The output is 40 volts, at about 2 or 3 amps. A battery charger will work, but will be much slower, due to the lower voltage.

You use a spring ground clamp for the ground, on the work, close to where you are polishing.

You use a "wand" for the positive- I made mine from a scrap piece of

Then dip in your mild phosphoric acid or Citri-Surf liquid. You dont want the metal of the wand to touch the stainless, you want the electricity to conduct thru the wet fiberglas tape.

the fiberglas will burn and char after a while, and need to be removed, tossed, and replaced with new.

Works great for removing weld discoloration. Not so good at removing blackened stainless that has been forged- for that, I have to send it out to a commercial house that uses a 100 volt power supply that is as big as a refridgerator. And commercially, they find it helps to dip the piece in a bathtub of phosphoric, which they heat to 120 degrees or so.

How about fine stainless steel wire brushes. .006" SS wire end brush in a die grinder is the preferred method for large Stainless fabricators and DOD people because of EPA and other OSHA considerations using chemicals...AND it's a lot cheaper and better!!! ...really!

I have to beg to differ. While I would not call myself a "large stainless fabricator" I do fab up somewhere between 4 and 6 tons of stainless a year for the last 5 years or so. And if I was wire brushing every weld, well, lets just say my kids would not be wearing shoes. Or eating much.

I can have a relatively unskilled guy electropolish welds at 2 or 3 times the speed of wire brushing them, and it is a much higher quality cleanup. Especially in complicated fabrications like I build, there are many situations where you just cant reach the whole thing with an air powered die grinder with a wire brush in it. Plus the little bristles fly thru the air and stick into your skin and clothes, which gets annoying after a few hours of it.

I send all my work out to a commercial electropolisher, who uses a

And much of what I do is very heavily forged stainless, where the surface is black when we are done forging, and the chromium in the outer layer of stainless is burned off. You can wire brush all day and not get down to the pure stainless again- but 20 minutes in the electropolish tank, and its bright and shiny. And it stays that way, outside, for years. I have had problems with wire brushed stainless discoloring after a year or so outside in the elements.

But, But, but...I don't make chemicals!

But, I DO make Stainless Steel brushes, kinda' skews my way of thinking. I think people should use wire brushes instead of toilet paper.

Dont worry, I buy brushes too- not trying to put you out of business.

Those rectangular ones with the one or two flat "bristles" per hole, would be just about right for the average Liberal.

Btw..they make GREAT shoe brushes when screwed to a board. Gets mud and s*it right out of my waffle stompers in short order.

Gunner

"I think this is because of your belief in biological Marxism. As a genetic communist you feel that noticing behavioural patterns relating to race would cause a conflict with your belief in biological Marxism." Big Pete, famous Usenet Racist

Then buy em from Tom. He makes F****ng fantastic ones..so its a win win for you both.

Gunner

"I think this is because of your belief in biological Marxism. As a genetic communist you feel that noticing behavioural patterns relating to race would cause a conflict with your belief in biological Marxism." Big Pete, famous Usenet Racist

We do alot of stainless pipe in my shop for transport of Liquid Nitrogen with the Oil industry. High quality work with strict procedures. Wire brushes are what we use.

Take a look

Gunner

"I think this is because of your belief in biological Marxism. As a genetic communist you feel that noticing behavioural patterns relating to race would cause a conflict with your belief in biological Marxism." Big Pete, famous Usenet Racist

The phosphoric acid and citrisurf may be relatively benign, but I'm not sure the same can be said for the witch's brew of metal compounds and ions generated during the electropolishing process, especially the chromium compounds and ions. Hexavalent chrome is particularly nasty, being a rather potent carcinogen and mutagen -- definitely not something you want to be handling much or dumping down a storm drain. Unfortunately, my chemistry knowledge is way too rusty (no pun intended) to know which forms of chrome and/or other nasties might be generated during electropolishing. Maybe the commercial firms you use could give you an idea of what chemicals you're generating and pouring onto your driveway.

Bert

Let me quote! Call me toll-free, 888-411-3265

(What kind of fishing you got around there?)

On Tue, 08 Aug 2006 10:58:22 GMT, with neither quill nor qualm, Gunner quickly quoth:

Good idea, you two. (Tom, he'll need samples of each, too.)

P.S: I forgot to thank you again for the McMaster 112 catalog, G.

- Yea, though I walk through the valley of Minwax, I shall stain no Cherry. ---

On Thu, 10 Aug 2006 06:27:40 GMT, with neither quill nor qualm, Gunner quickly quoth:

They're only going for $5-20 lately...not even 1/10th of a payment.

So, did Tawm's catalogs and samples arrive yet?

P.S: Didja ever get those pics of your hottie li'l neighbor for me? I wish I'd known her back when I was that mixed up (more drunk than druggie, by far, though.)

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