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Krunch
01-29-2012, 12:13 PM
I came into a big box of drill bits that I assume are dull, and now that I have a Drill Doctor 750X, I plan to sharpen them.

They all have a light coat of rust, and I'd like to remove it before sharpening to avoid loading the grinding wheel with rust.

I was planning to de-rust them with the electrolysis method (DC current with sodium carbonate as an electrolyte, with the drill bits attached to the negative pole of the DC power source, I can't seem to get the cathode-anode terminology straight) but before I do it, I figured I'd better check with people who know, to make sure I'm not going to ruin all these drill bits.

Is this an OK plan to remove the rust from these drill bits?

Thanks in advance for any advice.

lakeside53
01-29-2012, 12:30 PM
It will work fine.

I just toss mine in Evaporust.

Krunch
01-29-2012, 12:51 PM
Thanks Lakeside.

What's Evaporust? I googled the MSDS and see it's slightly acidic...I considered a soak in dilute HCl but decided against it for fear of leaving HCl in rust pits...

J Tiers
01-29-2012, 01:02 PM
Just say NO to HCL.....

Use phosphoric.... should take maybe 10 to 20 min max, works well, no power supplies, wires and tubs and electrodes etc.

Electrolysis "works" but the results are no better than simpler methods, in general.

With HSS, phosphoric works VERY well, I have had milling cutters come out sharp and usable. Will not keep etching the parts. Acids are not evil chemicals, they just do what they do.

HCL however, will rust everything in your shop..... phosphoric will NOT.

ikdor
01-29-2012, 01:37 PM
And if you don't have access to phosphoric acid, you could just get a bottle of coke. Lot's of phosphoric acid in there :)
No Joke, it works.

Igor

Blazemaster83
01-29-2012, 01:46 PM
Don't mean to try to steal the thread, but I have a bucket of large MT drills that came with an old drill press I restored last year. They are heavily rusted but I imagine would still be good if I get the rust off. Will coke work for this as well? I was going to soak in the electrolysis tank, but it's a pain in the ass to get set up. Evaporust is a little too expensive for me, but cola isn't.

Tony Wells
01-29-2012, 02:00 PM
If you want to use a cheap, no hands method, go to a feed/seed store and get a bit of feed grade molasses syrup, and dilute it roughly 10:1 with ordinary water. Immerse the rusty parts, or whatever, and give it a little time. It's now a really fast method, but it is cheap, and it works.

lakeside53
01-29-2012, 03:08 PM
Thanks Lakeside.

What's Evaporust? I googled the MSDS and see it's slightly acidic...I considered a soak in dilute HCl but decided against it for fear of leaving HCl in rust pits...


It's so slightly acidic it's almost not! Evaporust only removes rust -not iron; no residual issues.


You can buy phosphoric acid at most hardware stores. Look for the Ospho brand.

Black_Moons
01-29-2012, 03:26 PM
Evapo rust is pertty good stuff if you can totaly submerse the object, I used it on some chisels and they turned out really well.

Lack of totaly submersion results in 'lines' at the liquid level that don't like to come off.

Apparently its safe to leave stuff in evaporust for days if not weeks on end without non rust getting eaten. However its good pratice to quickly dry and oil coat once you take it outta evaporust.

Does tend to turn the metal a little darker, but looks OK.

RetiredFAE
01-29-2012, 03:35 PM
I just soaked a large number of rusted auger bits and standard twist drill bits I was given in a bucket filled with Wal Mart 99 cents a gallon 6% plain white vinegar.

About a two hour soak, and a quick pass with a brass brush and they were clean and bright.

daveo
01-29-2012, 03:42 PM
I use the evapo-rust, and love it! Harbor freight has it...:D

Rosco-P
01-29-2012, 06:25 PM
Is this an OK plan to remove the rust from these drill bits?

Thanks in advance for any advice.

Yes it is. It's also okay to leave you electrolytic setup sitting around hooked up (but turned off) for the next time you need it. IMHO, Evapocrap is overpriced, does nothing that the electrolytic method won't do.

daveo
01-29-2012, 06:33 PM
IMHO, Evapocrap is overpriced, does nothing that the electrolytic method won't do.

Except run up your electric bill, make toxic gas and have a tank full of toxic chemicals when your done,:D

Dr Stan
01-29-2012, 06:44 PM
Except run up your electric bill, make toxic gas and have a tank full of toxic chemicals when your done,:D

The only thing in the water should be iron oxide, hardly a toxic chemical. That assumes of course you haven't used electrolysis on items that are covered with grease, oil, lead based paint, etc.

While I have not used electrolysis on drill bits, it sure did a fantastic job on my milling machine table and other parts.

John Stevenson
01-29-2012, 06:49 PM
I use wall and patio cleaner diluted about 4 :1
Also removes the black scale off hot rolled steel.

Works for me.

http://www.stevenson-engineers.co.uk/files/derusted%20drill1.jpg

One of a handfull of old drills I was given.

http://www.stevenson-engineers.co.uk/files/derusted%20drill2.jpg

24 hours in the patio cleaner with a brand new laser cut plate to get the scale off it. Non treated plate as pattern.

http://www.stevenson-engineers.co.uk/files/derusted%20tap1.jpg

Tap I found in the bottom of an old toolbox, been outside for 15 years and was a solid lump of rust. Sorry no before picture as i never thought to get one.

http://www.stevenson-engineers.co.uk/files/derusted%20tap2.jpg

You can still read the etchings on it.

Rosco-P
01-29-2012, 06:57 PM
Except run up your electric bill, make toxic gas and have a tank full of toxic chemicals when your done,:D

$20 a gallon for Evap-o-crap buys a lot of killowatts. No toxic waste, unless you're an idiot and use stainless steel electrodes. I use old graphite electrodes from an EDM shop, water stays clear, no red sludge. Toxic gas? Exactly what kind?

Krunch
01-29-2012, 07:37 PM
Questions for those of you who are using acid (as opposed to electrolysis) to remove rust:

1. Do you first de-grease with a solvent and/or a base like NaOH to remove grease?

2. After the acid soak, do you go back to a base to neutralize any remaining acid?

Despite the novelty appeal of electrolysis, I would like to "get the job done" quickly if I could do it by degreasing, pickling, rinsing and then rinsing with a weak base like ammonia...

Thanks again for all the replies.

gnm109
01-29-2012, 07:46 PM
Just say NO to HCL.....

Use phosphoric.... should take maybe 10 to 20 min max, works well, no power supplies, wires and tubs and electrodes etc.

Electrolysis "works" but the results are no better than simpler methods, in general.

With HSS, phosphoric works VERY well, I have had milling cutters come out sharp and usable. Will not keep etching the parts. Acids are not evil chemicals, they just do what they do.

HCL however, will rust everything in your shop..... phosphoric will NOT.


Yep. I have a gallon of 70% phosphoric. It's about $20 a gallon from the local chemical supply. I cut it to about 30% for rust removal. It will last a long time. It's very handy stuff.

lakeside53
01-29-2012, 07:55 PM
All the common processes have their place. For brute force rust removal, acid or electrolysis are fine. Don't leave anything in the acid for longer than necessary though - it will continue to eat the wrong part, and... phosphoric leaves iron phosphate as a coating. Sometime you don't want that (but it does make a great paint prep surface).

Evaporust: Won't affect paint or other metals. Bushings, electrical parts, or other attachments like zamac handles etc are safe. And.. it's so easy. I have a long plastic tub bath of it on my bench - lift lid, toss in and forget, sometimes for days... You can remove heck of a lot of rust with one gallon, and when after months it's back goo, it make great and safe moss killer.

gnm109
01-29-2012, 08:14 PM
Questions for those of you who are using acid (as opposed to electrolysis) to remove rust:

1. Do you first de-grease with a solvent and/or a base like NaOH to remove grease?

2. After the acid soak, do you go back to a base to neutralize any remaining acid?

Despite the novelty appeal of electrolysis, I would like to "get the job done" quickly if I could do it by degreasing, pickling, rinsing and then rinsing with a weak base like ammonia...

Thanks again for all the replies.


I will remove any grease ahead of time, although there usually isn't too much grease on rusty items. I use liquid degreaser like Gunk or kerosene or acetone. After the rust treatment, I rinse with water and clean the scum off with steel wool or a wire brush.

Phosphoric acid makes a nice rust preventative coating on clean metal as well. You can get it very dark if you heat the acid mix a bit. Of course, you should use eye and hand protection when handling acid and don't pour water into acid to dilute, etc.

J Tiers
01-29-2012, 08:18 PM
yep, basic degreasing, a rinse and cleanoff after done, nothing big. No need to neutralize.


Don't leave anything in the acid for longer than necessary though - it will continue to eat the wrong part,

Actually this is not true..... Phosphoric essentially stops when the rust is gone..... if you take out reasonably soon nothing happens.... If you leave in for many hours, a coating develops, which is similar to the coating that the electrolytic method develops. but the part is not attacked.

BOTH electrolytic and phosphoric WILL attack stressed parts like springs, and sometimes case hardened items. I would not advise using on springs, case hardened stuff can come out when done and will be OK. I once had problems when I forgot and left the parts in all day.

lakeside53
01-29-2012, 08:25 PM
For those interested, what Jerry is referring to in hardened steel is "hydrogen embritlement". A common consideration with electroysis of precision parts like lead screws etc..

Hmmm... Drill bits are hard..

Rosco-P
01-29-2012, 09:00 PM
For those interested, what Jerry is referring to in hardened steel is "hydrogen embritlement". A common consideration with electroysis of precision parts like lead screws etc..

Hmmm... Drill bits are hard..

The hydrogen embrittlement risk was de-bunked some time ago over on PM. Rusty springs are at risk with any method, often much of the wire has been eaten away.

lakeside53
01-29-2012, 09:16 PM
PM may have talked themselves out of it, but there a lot of reputable sources that say its an issue. Here's one of a few thousands : http://www.uni-saarland.de/fak8/wwm/research/phd_barnoush/hydrogen.pdf



If the only issue with spings is the rust, removing it isn't going to change the outcome.

Rosco-P
01-29-2012, 09:33 PM
No one said that Hydrogen embritlement didn't exist or wasn't a problem. Conclusion was that the items didn't spend enough time in the process for any significant amount of Hydrogen embritlement to occur.

gnm109
01-29-2012, 09:36 PM
The hydrogen embrittlement risk was de-bunked some time ago over on PM. Rusty springs are at risk with any method, often much of the wire has been eaten away.


I don't know about the PM "debunk" of hydrogen embrittlement but regardless, it's a reality. Aircraft parts rebuilders among others usually take care of this by placing parts in an oven at a specified temperature for a period of hours.

Although I hate to use Wikipedia, they have a nice article on it. It actually exists.

http://en.wikipedia.org/wiki/Hydrogen_embrittlement

From this link: SAE AMS 2759/9 Section 3.3.3.1 calls out the correct procedure for eliminating entrapped hydrogen.

gnm109
01-29-2012, 09:46 PM
No one said that Hydrogen embritlement didn't exist or wasn't a problem. Conclusion was that the items didn't spend enough time in the process for any significant amount of Hydrogen embritlement to occur.


The Wikipedia article mentions the time frame after use of acid. Apparently heat trreatment must be started within a few hours. It's of particular importance on things such as aircraft landing gear when they are rebuilt and re-plated. I once toured a plant that did nothing but aircraft gear in Burbank, CA. They would heat soak their parts after hard chrome plating and regrinding in huge ovens, sometimes overnight at high temperatures.

J Tiers
01-30-2012, 12:10 AM
NO.....

Embrittlement is a totally separate issue......

What I refer to is an actual attack of the stressed area, resulting in spring being eaten away and breaking, or pits eaten in case-hardened items.....

this is a stress corrosion issue, where the stress cracks the coating, exposes new material, and allows the acid or electrolytic action to continue when it normally would stop as the coating built up.

I first saw it when de-rusting a spring caliper..... the spring was cracked in two, and I found that it had been corroded away to about 1/3 of its thickness in a spot. Evidently then the stress was low enough that it stopped.

lakeside53
01-30-2012, 12:26 AM
OK, bad guess on my part!

But you maintained in an earlier post that acid only attacks the rust, not the metal? OK, you said " if taken out reasonably soon". I doubt the phosphate coating is a particularly good barrier for the acid anyhow. I've seen considerably more "erosion" then the orginal rust when left in overnight (error).

Maybe your sping was just "held together" with rust in the cracks and it fell apart when you ate away the rust?;) Sounds like a good use for evaporust :)

metalmagpie
01-30-2012, 08:32 AM
Uh .. bead blasting?

J Tiers
01-30-2012, 08:44 AM
But you maintained in an earlier post that acid only attacks the rust, not the metal? OK, you said " if taken out reasonably soon". I doubt the phosphate coating is a particularly good barrier for the acid anyhow. I've seen considerably more "erosion" then the orginal rust when left in overnight (error).

Maybe your sping was just "held together" with rust in the cracks and it fell apart when you ate away the rust?

Considering the spring was good prior to the dunking, I very much doubt it....... CLEARLY stress corrosion.

BOTH electrolytic and phosphoric do this.

As for "stopping", I STILL say that....

Ordinary water will wear away stone, given time........ And some acids will continue to work and must be watched like a hawk to spot the first point at which you can yank out the part.... Its a race between rust removal and base metal damage.

Since phosphoric finishes work in from 15 to 45 minutes, there is no big issue with trying to find the "end point". The solution stops bubbling, and you know you can take out the part..... if you leave it in a lot longer, you may get a gray coating, which normally washes off, or can be removed with light brushing, often with a nylon brush.

With electrolytic processes, if you leave the part in too long, I found that a hard black coating built up which was extremely difficult to remove. But I WAS able to remove that coating with phosphoric, as I recall :D

John Stevenson
01-30-2012, 10:22 AM
Thank Christ i only want to clean some bits up...............:D

michigan doug
01-30-2012, 01:26 PM
Ummm, wire brush?

A wire brush wheel on a pedestal/bench grinder is fast and easy, maybe takes a minute each. No muss. no fuss, no neutralizing, no cost except for the electricity.

If I had to use more exotic methods, I prefer the evaporust and dilute phosphoric acid about equally well...

Finest regards,

troy

jep24601
01-30-2012, 02:15 PM
$20 a gallon for Evap-o-crap buys a lot of killowatts. No toxic waste, unless you're an idiot and use stainless steel electrodes. I use old graphite electrodes from an EDM shop, water stays clear, no red sludge. Toxic gas? Exactly what kind?
An idiot huh! And how would that be? I use a stainless steel electrode in accordance with at least a half dozen recommendations I've seen. Also a lot easier to find than graphite electrodes.

Kenwc
01-30-2012, 02:41 PM
Personally speaking...

Electrolysis is an PITA
The acid in vinegar will eat away at the threads on bolts
Molasses - well I don't know but probably slow as molasses

Evaporust is my go to. Works flawlessly and fastest if you can keep the solution at about 90 F.

Black_Moons
01-30-2012, 05:58 PM
Ummm, wire brush?

A wire brush wheel on a pedestal/bench grinder is fast and easy, maybe takes a minute each. No muss. no fuss, no neutralizing, no cost except for the electricity.

If I had to use more exotic methods, I prefer the evaporust and dilute phosphoric acid about equally well...
Finest regards,

troy

Protip: Put a 2 or 3" wire brush into your drill press, crank to max speed, and swing the table outta the way (or lower it for use as a place to support your wrist)

Much easyer for small parts where you may need to hold them at funny angles to the wheel, And slightly less likey to eat if you slip. (Still, No long sleaves, nothing that can catch, Perticularly if your drill press isent some 1/4hp chinese wimp. (Even though I bet the momentium on the motor could snap some fingers off, my belts pertty slack for that to happen)

mike4
01-30-2012, 06:20 PM
An idiot huh! And how would that be? I use a stainless steel electrode in accordance with at least a half dozen recommendations I've seen. Also a lot easier to find than graphite electrodes.
The carbon electrode in C size ordinary batteries will work if you are desperate , i have used them in electrolysis cleaning of small parts for an engine I once helped rebuild.
EDM's are not as common here as in the US.
Michael

J Tiers
01-30-2012, 08:18 PM
An idiot huh! And how would that be? I use a stainless steel electrode in accordance with at least a half dozen recommendations I've seen. Also a lot easier to find than graphite electrodes.

I did do that once...... Got a good deal of chrome-yellow foam....... that was the LAST time I did that, and I ain't sayin nothin about the hazmat service I used.............

Rosco-P
01-30-2012, 09:09 PM
An idiot huh! And how would that be? I use a stainless steel electrode in accordance with at least a half dozen recommendations I've seen. Also a lot easier to find than graphite electrodes.

http://antique-engines.com/stainless-steel-electrodes.htm

Graphite electrodes can be found in EDM shops, smelters, Fleabay, even D cell batteries. They aren't consumed quickly like scrap steel or rebar and keep the tank clean.

Video Man
01-30-2012, 10:03 PM
For surface rust like the OP is discussing, may I suggest vinegar and salt are a cheap and effective remedy? Unlike stronger acids, the vinegar does not remove metal (unless, I suppose, you left it for a very long time). It seems to loosen the rust, rather than dissolve it; in fact, after soaking it looks as if nothing has happened. However, a quick brush with a brass-wire brush removes the rust nicely. Salt is counter-intuitive for steel, but a good rinse in clear water and thorough drying seems to take care of it. Sample here was a tablespoon of salt in about 4 oz of cheap white vinegar:
http://i1053.photobucket.com/albums/s474/hsmuploader/rust.jpg

Redirish
01-30-2012, 10:29 PM
Steve, you beat me to it, I have used vinegar to very good effect as a rust remover. Learned about from my Dad, he told me many years ago that during the Depression they couldn't afford new files on the farm but vinegar was always on hand, so they soaked their files overnight in it and it made them cut better.

J Tiers
01-30-2012, 11:34 PM
Vinegar works, but the file story makes it reasonably clear that it does eat the metal enough to sharpen file teeth. That's how that service does it... some acid, dunno which.

Lots of ways, all work, some are more hassle, some need careful watching, some have the chance of "collateral damage" because the acid corrodes everything for 6 feet around, or has no 'end point" where it stops acting on the steel..

Your choice......

I like the phosphoric, because it 'sets up for work" in 30 seconds, works while I do something else, and isn't fussy if I am a bit late checking up on it.

You like electrolytic cleaning? Go for it.

You use muriatic? Fine for you, not this boy.

BobL
01-31-2012, 01:05 AM
I occasionally use phosphoric and hydrochloric for quick rust clean ups but if I want to use a set and forget method then I use electrolysis - followed by a phosphoric acid coat.

Here's an example of 24 hours in my electrolysis bath.
http://i1124.photobucket.com/albums/l570/BobLx/Fitchplate1.jpg
The fish plate had been used as a marine dead weight and had been in salt water for a couple of months and then had been exposed to air for about a year.

The conversion is by no means perfect but given the initial state of the object I'm happy with it.
Of course it starts to rusts very quickly (minutes) from here onwards so I paint it with dilute phosphoric and dry it in a hot BBQ oven. The phosphoric does etch it very slightly but the final grey coating is quite rust resistant.

Here is another before and after shot
http://i1124.photobucket.com/albums/l570/BobLx/ViceBA.jpg

jep24601
01-31-2012, 09:02 AM
Some products combine hydrochloric and phosphoric acids so that you get the rust eating power of hydrochloric and the protective properties of phosphoric. I have tried all the methods mentioned and there is no one universal procedure I would recommened as it all depends on the condition of the item in question though in general I would avoid hydrochloric acid except for the encrusted near unsalvageable or with dilution in conjunction with phosphoric in fuel tanks.

If an item is not pitted then varous stages of wire brushing can bring suprising results especially with shafting. Otherwise phosphoric acid is a great stand-by.

No mention yet of carburettor cleaner. It does a great job on small parts in a gallon can. Nasty stuff though.

Spookydad
01-31-2012, 10:31 AM
Where can I find phosphoric acid?

Neil

vincemulhollon
01-31-2012, 10:52 AM
Where can I find phosphoric acid?

Go to Home Depot or local equivalent. Paint department. Yes, I said PAINT, I know its crazy, but true. Phosphoric acid cleaner is used to clean masonry before sealing it. Look in the floor and deck area of the paint dept not so much the wall paint area. The stuff I have came in a blue plastic container of the "antifreeze" external appearance (like, a rectangle with a handle on top) and the title of the product was "phosphoric acid masonry cleaner" or something very much like that (label fell off). Whatever you do don't buy muriatic acid which is a totally different product, if it doesn't list phosphoric on the label don't get it. Expect to pay a bit more for it than a similar volume of drain cleaner... It doesn't really "go bad" it just gets neutralized in use so it works slower, so use it till it doesn't work anymore, which is ... a really long time unless you've got the industrial operation going. My container must be years old, but it just keeps working. Don't store it where kids and animals will drink it, don't store it on top of/over priceless antiques, etc. Its not nearly as dangerous as antifreeze so treat it like antifreeze and you'll be all good.

In the HD "glue" aisle I once found naval jelly, which is phosphoric grease, which works pretty well on something you can't dunk tank because its too big. I haven't seen that lately, or maybe they restock it elsewhere now, which is too bad. Its single use only so it gets kind of expensive to use.

Boucher
01-31-2012, 11:10 AM
Look for Ospho at HD or paint hardware stores

J Tiers
01-31-2012, 09:13 PM
HD now has a Jasco phosphoric sold as a rust remover.... by the gallon.

Lowe's does not have it... too dangerous for the Lowes customer, I guess..... they don't have much drain cleaner either. But they sell sharp drywall screws....and knives...... go figure.

Tony Wells
01-31-2012, 09:24 PM
Lowes Prep and Prime (Jasco) Phosphoric Acid

justanengineer
01-31-2012, 09:51 PM
Stronger acids are good cleaners for those hand tools you dont really care about, but I wouldnt take them anywhere near surfaces which require oil or you would like painted/plated. Neutralizing it after its soaked into iron can be painful, and you wont realize its seeped back out until youve reassembled a machine and ran dry of oil, paint/plating is bubbling, or had other issues. Been there, done that, dont want any repeat performances.

I once spilled a small can of muriatic acid in the shop. My machines had noticeable rust spots in the less oily areas within hours after the cleanup was completed, and the effect hung in the air for ~2 weeks.

J Tiers
02-01-2012, 12:14 AM
That's the nice thing about phosphoric.... won't do that. It's even a good paint prep if you don't wash off the thin coating of phosphate.


Lowes Prep and Prime (Jasco) Phosphoric Acid

No such nanymule in our store..... I've looked 3 different times when I was there for other stuff and remembered I was gonna get some... had to go to HD..

Tony Wells
02-01-2012, 01:53 AM
Odd. I saw that they had taken it off their websales venue, but figured it would be in store. I just bought them out here to set up a small Manganese Phosphate system. Cooked in some Manganese Dioxide....worked well.

EVguru
02-01-2012, 05:27 AM
An idiot huh! And how would that be? I use a stainless steel electrode in accordance with at least a half dozen recommendations I've seen. Also a lot easier to find than graphite electrodes.

From; http://antique-engines.com/electrol.asp


Why you should not use stainless steel electrodes for electrolysis
Many people using the electrolysis method for rust reduction swear by stainless steel, stating (incorrectly) that it's not consumed, stays clean and seems safe.
Stainless steel is indeed consumed when used in the electrolysis process, although slowly. The main problem with using it is the hazardous waste it produces. Stainless steel contains chromium. The electrodes, and thus the chromium is consumed, and you end up with poisonous chromates in your electrolyte. Dumping these on the ground or down the drain is illegal. The compounds can cause severe skin problems and ultimately, cancer. Hexavalent chromate is poisonous. These compounds are not excused from hazardous waste regulations where household wastes are.
These compounds are bad enough that government regulations mandate "elimination of hexavalent chromate by 2007 for corrosion protection."

Does your electrolyte turn yellow? That's a sign of chromates.

If you have been using stainless steel for the anodes (positive electrodes), wear rubber gloves when working with or near the liquids. If you need to dispose of it, allow it to evaporate into powders and dispose of the powders in sealed containers during your local "hazardous waste clean-up days".

Best bet - don't use stainless steel no matter how tempting it is.

gnm109
02-01-2012, 08:27 AM
I buy phosphoric acid in gallons of 70% strength at a chemical warehouse in my area. It's about $20 a gallon.

The various janitorial and home products sold in places like Lowes and Home Depot are usually lower in strength and are therefore more costly relative to their percentage of acid.

jep24601
02-01-2012, 09:34 AM
As one of the "idiots" who have use stainless steel for quite some time I feel that the Hexavalent chromium issue has gone a little viral. The stainless steel electrode is consumed at such a slow rate that it appears to many users not to be consumed at all. Using gloves is normal for me also. I found these seemingly reasonable comments elsewhere on the web:

<<** Note ** Stainless steel can be used because this material seems to last longer and cleans easier. BUT, concerns have been raised which propose that as the electrode breaks down, the chromium in stainless steel becomes a compound (hexavalent chromium) which ends up in the liquid (or as a gas in the bubbles) and there is the potential for the mist from the bath to become airborne and inhaled. LONG TERM exposure to the skin has been related to skin disorders and LONG TERM inhalation of fumes has been linked to lung cancer.
HOWEVER, the US Occupational Safety & Health Administration has a considerable write-up on Hexavalent Chromium (CrVI) and say CrVI is produced from the high tempertures produced when welding, grinding or melting stainless steel or other metals containing chromium. This has been echoed by people I have spoken to about this, all experienced, qualified PhD Chemists and Materials Engineers. I now believe that the temperatures that occur with electrolysis as described herein are not nearly high enough to pose a risk. If you disagree, send documentation written by qualified experts that address the process of electrolysis in a water bath. Heresay and rumours just don't cut it.>>

HSM'ers might want to be aware that the risks of exposure to hexavalent chromium are much higher when welding stainless steel.

J Tiers
02-01-2012, 07:54 PM
I certainly do not claim that electrolysis creates hexavalent , or any other particular form of, chromium.

All I can suggest here is that chromium in a water-soluble form (presumably some "salt") which evidently is present since it exited the metal into the water, seems to be produced by using stainless steel electrodes in the de-rusting process.

When doing so, I found the foam produced to be a characteristic yellow/orange color. When using any other piece of steel I found, I did not get that result. Chromium is the likely culprit.

In general, there is no good reason for producing chromium salts as a byproduct , and since they are considered to be un-good in general, I decided not to produce them.

I later decided there was no advantage to doing electrolytic de-rusting itself, so the point is now moot for me.

If you do that process much, you may have a more "industrial" exposure, and that is something to consider.