Stainless Steel *not* safe for electrolysis?

[Hylourgos]

In a recent thread ("Handplane Terminology"), Charlie Self linked us to a nice article of his ("Plane Business") discussing hand planes and their care, including a description of using electrolysis for rust removal. In it, he advocates using SS as a conductor since it will last longer.

Recently, I came across a site by Bill Dickerson detailing how dangerous it is to use SS in this process, since it produces hexavalent chromate as a by-product of the waste--a toxic carcinogen.

The warning can be found at:

site explaining electrolysis as rust removal: I'm no chemist so I won't pretend I know this information to be true, but it's serious enough to stop me from using SS. Bill's site is the only thing I've read warning against its use.

I'd like to canvass this groups' experts who know about chemistry: does Bill have it right, is it unwise to use SS in this process?

Thought everyone else might want a heads-up too....

Regards, H

[Anthony Diodati]

[Andy Dingley]

I'm not an electrochemist. Hexavalent chromium is indeed a big nasty. However I wouldn't expect it to be produced in these circumstances.

[Micro*]

DON'T DRINK THE WASTE!!!! More people die or are seriously injured from the hydrogen hydroxide used in the process than from the chromate.

-- "Shut up and keep diggen" Jerry

[Hylourgos]

Well, did you read the link supplied above? Bill explains that it *is* produced in just this situation.

I would expect that anyone with a decent chemistry class under the belt would be able to understand and explain it.

H.

...who was too busy taking shop classes to bother with chemistry.

[Andy Dingley]

OK then - Yes, and he's wrong.

Of course, _I_ may be wrong. Chromium chemistry is funny stuff and I certainly don't understand it. So I asked the best chemists I do know, and they didn't expect hexavalent chromium to be produced by this route either. Now sadly they're not electrochemists either, they're organic chemists, so they (as they admitted) might be wrong too. However at least one of them does handle chromic acid on a regular basis, so he's not unfamiliar with the species.

As a terse and unreferenced article on "oldengines.org", contradicting all the chemistry I do have access to, I see it as his problem to prove the case.

[Hylourgos]

Ha ha...Yeah, oldengines.org might not be the best source to impress the chemists. I'll see if I can get some real chemists to weigh in.

However, considering the severity of its toxicity, I thought I'd post what I'd read just in case it is true and others out there are using it regularly. Charlie is, apparently--and hasn't he had enough shit go wrong lately?

' Just remembered too: wasn't it chromium hexavalent that was the featured toxin in "Erin Brokovich"?

H.

[Andy Dingley]

Yes. Which is why every net.k00k is gibbering about it.

[George]

Long time since inorganic chemistry, but doesn't hexavalent demand more energy to form than the trivalent? Wonder if it would be much of a player in battery-operated electrolysis.

[Hylourgos]

Good point, your scepticism is well founded, and I hope you're right--not the least because I found what may be the best SS conductor for electrolyis: flexible SS gas connector sections. They're about 2' in length and will bend to form a perfect shape around whatever you're derusting. Mine were 25¢ ea. at a Sears bin sale.

I've posted the question on a chem. NG and I'm going to e-mail some chemists I know. Will post whatever I find out.

Regards, H.

[Nate Perkins]

The following link is an okay explanation of the process involved:

don't think you'd get any significant amount of hexavalent chromium generated at the cathode. The redox potentials to create Cr+6 are not nearly as favorable as many of the other ones involved (just regular iron for instance). You can check that by looking up a table of electrochemical potentials in any chemistry text.

I've got a good science background, but this is a little outside my field. Remember, free advice like this is often worth exactly what you paid ;-P

Cheers.

[none]

I am a chemist and a regular reader of sci.chem. I didn't see your request there but that newsgroup has deteriorated to the extent that I tend to browse rapidly.

Put your fears to rest. You won't have a problem with hexavalent chromium. It is not likely that Cr+6 will be produced but if you produced Cr+6 at the anode it would be first in line to be reduced at the cathode.

[Mike]

You posted it to sci.engr.chem which is not a heavy traffic site. Try sci.chem. There are some *very* knowledgeable people there. It also has more than its fair share of nitwits so be sure to separate the wheat from the chaff in the answers you get.

Cheers, Mike

[Hylourgos]

Hi none and Mike,

Thanks for replying, and directing me to NGs with more traffic. I went ahead and posted on sci.chem. First though, I searched sci.chem and got some interesting threads. Most seem sceptical that it (Cr+6) is much of a problem, but I'll wait to see what comes of it.

I'd just hate to mess with some combination of chemicals about which I'm ignorant and produce a serious problem.

Regards, H.

[Michael Daly]

OTOH, if you use plain old iron instead of stainless steel, you don't even have to think about this stuff. You can use zinc as well.

Mike

[charlie b]

Ah, the things we worry about.

Jewelers use cyanide eggs dissolved in water to clean rouge, tripoli and gunk off of watch parts and jewelry. An old (stress old - as in being in his late 80s) jeweler in SF used to leave a pot of the stuff on a low set burner all the time. He'd drop his false teeth in the solution after lunch, let 'em cook a few minutes, take 'em out and run them under the faucet for 10 seconds and pop his teeth back in place. Had been doing this for over a half century. His false teeth were always nice and white and clean.

He forgot to turn the burner off one night and when he came in in the morning he walked into a room full of less than alpine fresh air. He got sick enough to call

911. At the hospital they analyzed his blood and found the cyanide level high enough to kill a couple of normal people. Him - it just made him feel sick to his stomach.

Anyone want to discuss cooking in aluminum pans and maybe get Alzhiemer's disease?

charlie b

[Scott Lurndal]

I'd be more concerned with the Al in most anti-perspirants.

scott