Rust removers

I tried electrolytic method and found it cumbersome and inconsistent.

I use diluted muriatic acid these days and it works very well for me. Easy and works in every crevice. The post-treatment handling is all-important, basically you need to dry the part as soon as possible, and either oil it or paint it depending on your use of it.

Google "electrolysis rust removal". I've used it on a number of rusted parts, does not harm the parent metal.

----------- Be remined that Naval Jelly does not remove rust but converts it from the red to black oxide. Best solution appears to be electrolitic cleaning. Use a plastic storage container from walmart for the tank and your battery charger. Several threads on this in this NG.

Usual solution is washing soda [baking soda also works] at the rate of a tablespoon to the gallon, which is pretty tame.

google on for > 700 hits. start with

Unka' George [George McDuffee]

------------------------------------------- He that will not apply new remedies, must expect new evils: for Time is the greatest innovator: and if Time, of course, alter things to the worse, and wisdom and counsel shall not alter them to the better, what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman. Essays, "Of Innovations" (1597-1625).

Immerse it in vinegar, check it in a month.

DONT EVER USE A STAINLESS STEEL ANODE or you'll risk making some seriously toxic waste. Only do it in a well ventilated area as Hydrogen gas is produced in significant quantities.

The archeologists use electrolytic derusting at very low current levels to conserve iron cannon and the like. They are interested in preserving every last detail of the surface they can. For the rest of us, a quick result that doesn't do significant damage is preferable. For most things its good if you are passing enough current to keep the derusting bath warm, but you dont want it to boil.

I'd strongly reccomend putting some sort of ballast resistor in series with the power supply to limit the current in the event of a short circuit. Avoids all sorts of unwanted excitement. I usually use a car headlamp bulb which at 60 watts rating will pass 5 amps when shorted. If things are going well, it will be glowing dull red for most parts thast will fit in a tank of about 2 litre capacity.

It helps to keep the worst of the corrosion knocked off the anode by wire brushing it at intervals if you are either doing several parts or have something big derusting over several days.

It works well with just about any alkali. A drop of detergent in the solution can help with wetting. Used solution can be stood till it settles and kept for next time.

P.S. Iggy, your favorite hydrochloric acid rust removal method works pretty well for bulk rust removal but will etch away some good metal and leaves the surface chloride contaminated which will make further rust damage more likely. If you used the acid to get 90% of the rust off, washed the object well then finished it by electrolytic derusting, you'd get a much superior result.

I use Zep Metal Prep Dip Rust Remover from Home Depot. I can walk away and leave parts in there till I get around to using them. Karl

Iggy's reply is also what I use, but in addition to thoroughly washing in clean water, I also have a bath of baking soda and water. To completely neutralize the acid, after which I wash again, Steve

I also use baking soda (sodium carbonate) for electrolytic cleaning. I use a variable power supply so that I can control the current when de-rusting small stuff, but a light bulb in series will work for a battery charger. assume about four volts for the electrodes and drop the rest with a bulb. Due to the constant current characteristic of bulb filaments, you won't be far off if you assume a 5W bulb will give you .5A, 55W==4.5A etc. I use lead anodes because they keep the solution cleaner than steel anodes. There is some lead carbonate formed, but it's not a major issue as it's insoluble. Just don't eat it! Major issue with stainless anodes other than worries about formation of hexavalent chromium compounds is that they get inhibited by the current and eventually stop working until the current is reversed or they are abraded.

For large objects that won't fit in a tank (lathe cabinets), I've used phosphoric acid thickened with cellulose wallpaper paste with about 20% acid by volume. This appears to be close to what Jenolite is. The advantage of phosphoric acid over others is that it won't encourage further rust in crevices. It is a fairly weak acid compared with hydrochloric and sulphuric and the waste products are fairly benign. Don't pour it into the river, but don't worry about diluting and watering the garden with it. It'll green up your grass! Disadvantage is that the parts need scrubbing or pressure washing to remove the crud that gets left on them.

Mark Rand RTFM

Iggy is right diluted muratic is fast and cheap, wants to re-rust. I stop it with a squirt of purple engine cleaner (strong caustic) after a water rinse. Still need to oil or paint.

For many parts I like phosphoric acid better. I buy it already diluted as "Lime Away" cleaner at my local Fleet Farm. This works differently, it converts rust to a black iron compound that won't re-rust. If you'd rather pay more, you can get the same chemistry in Naval Jelly or rusty metal prep.

The electrolytic method others have mentioned is best for a small amount of rust on a delicate part.

Karl

I thought bluing was black oxide and I'm fairly sure that Naval Jelly takes bluing off. What up with that?

Wes

Define "small amount of rust" I have used electrolytic cleaning on car frames, trailer frames and entire body shells.

The catch is knowing what to use. Baking soda doesn't work very well. What you want to use is Washing Soda, AKA Sodium Carbonate, AKA PH Plus pool chemical.

Fill the container with water. Now attach the wires to the parts and toss them in the water. Now add the washing soda to the water until you hit the maximum current those parts require (just watch the needle on the power supply/charger) when the needle stops rising stop adding chemical.

Old Chipper had written this in response to

:

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72 Mach1 wrote:

Think I'll try it. Can you reuse the mixture or do you start new each time? Also put a few parts in a 50-50 mix of molasses and water. Found this on another forum hope it will work, had to give it a try sounds to strange to work, will post the results, later. thanks

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Ted Edwards (where is Ted these days?), who apparently knows a lot about chemistry and plating/derusting, posted his formula to the dropbox some years ago:

This is for "brush" type removal, rather than the tank method. I use it all the time and it works brilliantly. My power supply is a 4-Amp automotive battery charger. Since I had some EDM graphite on hand, I sawed off a slab for use as the electrode. But a graphite rod available from welding suppliers should be handier.

The formula is a bit more complicated than might be necessary, but Ted knows electrochemistry and I don't, so I follow his formula.

As for the tank method, yes, you can keep re-using the mixture until it's full of crud.

The black oxide that remains is similar to that left by phosphoric acid when you use phosphoric (Naval Jelly or pool acid) on thick rust, but it brushes off much more easily. I use a small stainless brush. Sometimes I've used muriatic (hydrochloric) acid to finish it off, but only if I'm going to paint afterward.

-- Ed Huntress

Molasses works but make SURE you wash it off very well. It also takes quite a while. I have tried just about anything while doing restorations and find electrolysis to be about the easiest and least labor intensive.

You can reuse the solution until it stops conducting. What I do then is run it through a homebuilt filter setup. Just a small pump with a LARGE filter. Then recharge the solution with some more chemical. Once it gets REALLY bad I run it through the filter then run it into the evaporator I built. That gives me the water back and the solids get tossed. Then I start over.

The tank you use is limited by your imagination. I have used tarps and pallets, large plastic totes, and poly drums.

Make SURE you DON'T try this process indoors. The process breaks the water down into hydrogen and oxygen and can REALLY ruin your day if it happens to build up and ignite. I use one of the cheap easy up structures to protect the set-up from rain.

Power supply wise a battery charger works fine.

I find that by using a warm solution, the process works better and of course faster. Rick

I don't mean to say it won't work. Just less trouble to clean a frame with muratic acid or a body panel with phosphoric acid. These materials are faster but a bit too rough on something delicate.

Karl

I use Evaporust. It is effective, less toxic and less hassle than acids. Also can be reused until it gets black. Relatively cheap if bought in gallon quantities.

I don't know. Never tried to make it.

The electrolytic approaches (power supply and baking soda, or white vinegar and as much salt as you can dissolve) tend to attack one metal of a pair connected together. In particular, people have tried using it on things with small springs attached, and the springs dissolved.

The other thing is that you should take it from the bath right to a hot water rinse, and once the metal is hot enough, withdraw it, wipe it with paper towels to remove most of the water, and as soon as it is dry, coat it with oil. Otherwise it will flash rust.

Like -- don't pick up a black steel tool which is out in the sun. :-) I grew up there. What part of South Texas? I was in Cotulla (about half way between San Antone and Laredo).

Well ... I was using a lab power supply which could output voltages from 0 - 36V, and from 0-5A -- with a current limit adjustment. The more current, the faster it will work -- or the more area you can clean in a given unit of time.

Keep rivets, screws, and springs out of what is being cleaned and you should be fine.

Good Luck, DoN.

And if you can't get them out due to the rust, they may come out just fine in the tank.