Electrolysis.

[Peter Bell]

I have been trying to resurrect some old hand planes, saws and other old tools which naturally have a lot of cleaning up to do.

One of the arrows in my quiver is the use of electrolysis which is sometimes followed up with a weak solution of diluted phosphoric acid and then some fine wet and dry paper.

I would be interested to know what you guys do. I have seen some articles where electrolysis is not recommended and others do. I have been impressed with the results I am getting but does anybody know what the negatives are regarding the weakening or degrading the metal it has cleaned the rust off.

Peter.

[Casey Gooding]

Once I discovered Evapo-Rust, I never looked back.

[Peter Bell]

Once I discovered Evapo-Rust, I never looked back.

Thanks for the reply. Can you tell me what the active ingredient in Evapo - Rust is.

Is it 80% phosphoric acid.

Peter.

[Roger Newby]

+1 for Evaporust. There's no acid in it. It's a proprietary water based product and really works great. Don't store or use in a metal container, it will in time dissolve thru.

Roger

[David Keller NC]

Thanks for the reply. Can you tell me what the active ingredient in Evapo - Rust is.

Is it 80% phosphoric acid.

Peter.

Evaporust is a combination of a chelator and iron sequestration chemical. The chelator is based on EDTA (ethylene diamine tetraacetic acid), the sequestration agent is a sulfo-pyridinium compound.

You can do basically the same thing with citric acid. Citric acid is a mild chelator (not as strong as EDTA), and of course doesn't contain a sequestration agent, so you generally want to mix it up fresh every time. It's very inexpensive from a home brewery supplier.

In my opinion, it's a lot less bother than electrolysis with sodium carbonate.

[Jim Koepke]

I have used citric acid and have been happy.

Most of the time sandpaper, steel wool and a single edge razor do the trick for me.

jim

[Peter Bell]

Evaporust is a combination of a chelator and iron sequestration chemical. The chelator is based on EDTA (ethylene diamine tetraacetic acid), the sequestration agent is a sulfo-pyridinium compound.

You can do basically the same thing with citric acid. Citric acid is a mild chelator (not as strong as EDTA), and of course doesn't contain a sequestration agent, so you generally want to mix it up fresh every time. It's very inexpensive from a home brewery supplier.

In my opinion, it's a lot less bother than electrolysis with sodium carbonate.

Thanks for the heads up about citric Acid, I will try to find some here. that has answered one part of the question.

I have no trouble with electrolysis set up. A plumber friend has set up a tank rescued from 250 mm ( 10 inches ) PVC drainage pipe for this set up. It helps when he has a few old saws that needed cleaning up and re handled, so it was a good trade off for both of us.

But the question remains does electrolysis have a drawback which will affect the integrity of the saw steel and other metal it is used on.

Peter

[Wilbur Pan]

The only two methods I've used for rust removal so far are elbow grease/WD40/Scotch Brite pad, and electrolysis. With electrolysis, there is the potential for hydrogen embrittlement. What can happen is that as electrolysis occurs, hydrogen can penetrate the iron lattice, form hydrogen gas, and become trapped there, leading to embrittlement of the steel. Over time this effect reverses itself as the hydrogen gas diffuses out of the steel.

My feeling is that this process can be minimized by doing the electrolysis slowly, with as little current as your power supply can deliver. With the rusty tools I've rehabbed so far with electrolysis, any cracks already in the tools have been a much bigger issue than hydrogen embrittlement.

[David Keller NC]

"But the question remains does electrolysis have a drawback which will affect the integrity of the saw steel and other metal it is used on."

Electrolysis will have no effect on the steel of tools itself. The voltages and currents are just too low to do anything - good or bad.

However, acid baths, chelator solutions and electrolysis are not the way to go on an antique saw if you wish to preserve the etch. All of the "quick and easy" immersion methods will pull the etch right out. You can sometimes restore the etch with bluing solution (see the Neander FAQ for Bob Smalser's "rehabbing and old saw" thread), but sometimes not if the blade's had a lot of rust on it in the past.

For a sawplate, careful scraping with a single-edged razor blade and some mineral spirits will clean the plate up enough for use, preserve whatever collector's value that it may have, and keep the etch intact. I think Pete Tarran's site has a description of how to clean up a saw plate by this method.

[Cliff Rohrabacher]

Phosphoric Acid ( the stuff in Evapo-Rust and Barkeeper's Friend) works well on steel, So does Brewer's grade pure Vitamin C (ascorbic acid.)

I have stripped rust blushes from Stainless Steel using Ascorbic Acid and - - - - - - of all things Acetic Acid (plain vinegar).

You can sharpen olf files in an Ascorbic acid soak.

I have tried muriatic (20% hydrochloric) acid on SST and found it stripped off all the passive chromium oxide rendering the Stainless aspect of SST worthless and rusting the metal worse.
Muriatic is also rough on mild steel and a terror on Cast iron. It pits the steel and penetrates the cast iron.

Ascorbic acid is the actrive ingredient in the SST passivating solution trade named "Cirtisurf."


As for Cast iron: Well any acid you use will penetrate the metal to some degree since cast is slightly porous. So you should be thinking of how you'll neutralize it. Backing soda works so does a calcium solution. but then ya gotta get the water off before rust sets in. I like pure Ethanol for water removal. It penetrates the microscopic crevices and bonds to the water making it flash off in atmosphere.

You could dunk it in Kero, fuel oil, or deisil too. Kero is the stiff in WD-40 that drives water off. But you still need to use a VOC to get the Kero off before painting.

[David Keller NC]

Cliff - If you wish, you can re-passivate the SST with phosphoric acid. It simply takes a quick wipe and rinse with the concentrated stuff (80%).

Muriatic (hydrchloric) acid, btw, is unique among the strong acids in its propensity to pit steel. The strength of the acid isn't the issue - strong sulfuric won't pit steel in the same way, though any strong acid will etch (eat) the iron in steel. In the case of HCl, it's the presence of the chloride iron that causes the damage - it's one of the reasons that seawater is so corrosive to metals in general.

By the way - the passivating solutions you refer to are actually citric acid, not ascorbic. They're closely related and for the purposes of removing rust, they do about the same thing.

[Bill Keehn]

I have been trying to resurrect some old hand planes, saws and other old tools which naturally have a lot of cleaning up to do.

One of the arrows in my quiver is the use of electrolysis which is sometimes followed up with a weak solution of diluted phosphoric acid and then some fine wet and dry paper.

I would be interested to know what you guys do. I have seen some articles where electrolysis is not recommended and others do. I have been impressed with the results I am getting but does anybody know what the negatives are regarding the weakening or degrading the metal it has cleaned the rust off.

Peter.

I was very impressed with the results of electrolysis. I did some stanleys last fall that I got at the flea market. If you want to preserve the details I think it is the best way. The only caution I have is that the metal will start to rust almost immediately after you take it out of the bath.

Rather than baking the parts to dry them as I've seen suggested, I sprayed the metal with WD-40. The WD stands for water displacement, and it seems to work well for that. The WD-40 evaporates quickly, so I wiped the parts down with a little 3-in-1 oil. The planes still look good with no new rust.