Haulin_in_Dixie

I came into a bunch of air tools that were submerged in New Orleans in the hurricane. One impact is a brand new one inch gun that on disassembly is perfect and new, except for the air motor area. Looking for ways to de rust the parts, I came up with this. I have no doubt that it will work and am currently trying it.




Rust removal (long post)

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Following is a technique that I have used with good success in removing rust (pitted) from tool and other metal parts. I am curious as to whether anyone has tried this for a rusted firearm? Most of the time, the rust I run across is only on the surface and a little oil and steel wool are all that is necessary. But if the rust is in deep pits or in places that you can't easily get to, this might be useful.


Rust removal using a battery charger

Electrolytic rust removal is a simple non-labor intensive method of removing rust from an object, using nothing more than water, washing soda, and electricity. There is nothing magic about the process; anybody old enough to remember chrome bumpers remembers the electroplating process. In the case of electrolytic rust removal, the system is plating rust from an object you want to restore onto a junk electrode.

The same process is also very effective for removing corrosion from brass and copper, using the same electrolyte.

The process is NON destructive, to the steel or iron object being derusted, unlike media blasting needle scaling or acid dipping. The only thing that will be removed is RUST. The best part, unlike abrasive blasting, ALL rust will be removed from the microporosity of the metal being derusted. When all rust has been removed the process will STOP by itself, and good steel will not be eroded.

The process does NOT restore the metal to original condition, it merely removes RUST.

When done PROPERLY, with Sodium Carbonate or Sodium Bicarbonate, electrolytic derusting will NOT harm steel, Babbitt, lead, copper, brass, or aluminum. That means with a properly sized tank, you can submerge and derust a complete Hit & Miss engine. Using other electrolytes can and WILL harm some metals, such as Babbitt or Aluminum.

SPEED: Lets face it, the object you want to derust didn't get rusty overnight, and electrolysis will probably NOT derust it overnight either. The speed of the process is determined by equality of surface area between the object being derusted, and the accumulating electrodes, as well as by the voltage/amperage applied, and the electrolyte used.

Here's a brief explanation of what is happening in the tank:

During the electrolysis as a general rule, ions are being replaced vs elements. So the Ferric Oxide is probably being converted to Ferric Carbonate. Also any pollutants that are in the original water and any contaminants on the part being derusted will lend their ions to the mix. There may be Calcium Carbonate, Sodium Chloride and who knows what else in there. Basically there will be Hydroxyls, Carbonates, Oxygen, Hydrogen, Sodium, Iron, and maybe some Calcium or Chlorine in the soup. The only compounds that will be lost will probably be Hydrogen and Oxygen; anything else will remain in the soup as soluble salts (some Sodium Carbonate and maybe Ferric Carbonate) or as solids which will either precipitate and fall to the bottom, remain suspended in the soup, attach to the anode or remain on the surface of the derusted part.

I'm just a dummy who knows the process works.

Solution: 1 tablespoon of Arm & Hammer Super WASHING soda per gallon of water. This is the BEST working solution for the electrolyte. On the off chance you can't obtain Washing Soda (sodium carbonate) in the supermarket laundry aisle, Baking Soda (sodium bicarbonate) will work, although it will offer slightly less productivity in the tank.
Over time, the solution level will drop due to evaporation and the breakdown of water into Hydrogen and Oxygen. Only water needs to be added to replenish the solution, no additional soda needs to be added.
If the tap water in your area has a high mineral content, using demineralized water may yield better results.

The solution will freeze, at about 30° Fahrenheit. Generally this isn't a problem, at least for me, because I don't enjoy working in a cold area. If the solution does freeze, it will easily thaw by applying voltage to the object being derusted and the accumulating electrode. Freezing will NOT harm the electrolyte solution. Frozen solution may harm some objects that are suspended in the solution when it freezes, so use common sense.

VOLTAGE: The process works best with either 12 or 24 volts DC, easily obtainable from a battery charger. Voltages above 24 volt don't really offer any greater efficiency, and generally seem to get wasted off as heat in the solution. Heat doesn't add anything to the process, other than wasting electricity.

AMPERAGE: Basically any DC voltage source will work, from a trickle charger to a plating power supply. Too much amperage, just as excessive voltage, wastes off as heat. The best way to regulate the amperage operating in the tank is by controlling the amount of submerged surface area of the accumulating electrodes.

POLARITY: Positive (+) DC is attached to the accumulating electrode, and Negative (-) DC is attached to the object being derusted. All you really need to remember is Positive Accumulates. If the polarity of the DC source is not known, attach the wires and energize the system. Small bubbles will rise from the NEGATIVE object. Correct a reversed connection immediately; allowing your prized object to accumulate material from the sacrificial anode can rapidly cause pitting. The bubbling is also a good way to verify that the process is working.

BATTERY CHARGERS - If you use a charger as a power supply, some of the newer "automatic chargers will not start generating current into the tank, unless you use a battery along with the charger.

ELECTRODES & OBJECTS BEING DERUSTED - Both need to be suspended so they cannot come into contact with the bottom of the tank or the sludge that accumulates there to prevent shorting the power supply, or wasting current by passing it through the sludge.

TANK - Plastic tanks work about the best, and that includes digging a pit and lining it with plastic sheeting. Unfortunately, my neighbor has taken an attitude, so I haven't been able to experiment using his pool as a tank, but he might go on vacation. The process can be done in a steel barrel, BUT exterme care needs to be used to preclude the barrel from becoming an energized surface, witch will eventually develope poroscity in the barrel.

The best anode material I have found is carbon or graphite. It works 24/7 and leaves the rust in the bottom of the tank, so you don't loose time cleaning the anodes, or loose operational speed due to coated electrodes. If you can't locate graphite electrodes, used lawnmower blades or old car leaf springs will work but they will require cleaning about every 4 hours.

Whatever you do, DO NOT use stainless electrodes; they make some very nasty hazmat called Hexavent Chromium that is POISONOUS and will give you nasty diseases, and it is absorbed through your skin.

The process works best "line of sight" so to speak, so multiple electrodes are often beneficial. Arranging several accumulators around the perimeter of the tank generally works well, and minimizes the possibility of short circuiting.

SCUM: As the process runs, a layer of brown (usually) scum will form on top of the solution. This doesn't happen 100% of the time, but a scum layer is not anything to worry about. Before withdrawing the object being derusted from the tank, it's a good idea to shut off the electricity, and skim off the scum before pulling the object.

CLEANING: When objects are removed from the tank, they will often have a black coating that looks like the object has been smoked. This is normal. The best way to remove this coating is to wash it using a stiff brush in a solution of dish soap and water before the coating dries. If the coating is allowed to dry on the object, it will be nearly impossible to remove.

DRYING: After washing derusted objects, the best procedure is to either sun dry or dry in a 200° oven. If you use your wife's oven be prepared to sleep on the couch, not that drying will hurt the oven but it will hurt your sleeping arrangements.

CONTAMINATION: In order to avoid contamination of the electrolyte solution, objects being derusted should have all grease, oil and dirt removed beforehand. Objects that have rusted in a salt water environment such as ocean water need to have as much salt leached out as possible, before electrolysis. Failing to remove salt first will radically shorten the useful life of the electrolyte solution.

CRACKS, etc.: Objects such as multi-piece assemblies that have mated surfaces are difficult to derust without disassembly. A great amount of time will be required to electrolytically remove rust between the sliding surfaces such as a vise. Pieces that have cracks will perform similarly in an electrolysis tank, and it will take time to remove the rust from the crack.

MULTIPLE PIECES: Assemblies of multiple pieces (such as machinery) usually require an electrical connection to each piece. Rust does not conduct electricity, so unless the pieces are connected cleanly together, generally the connected piece will derust while the adjacent piece remains rusted.

CONNECTIONS: It is necessary to make a good electrical connection to the object being derusted and the power supply. As previously stated rust is not electrically conductive, so it may be necessary to scrape or grind a connection point on the object before the process can begin. Alligator clips are generally acceptable connectors BUT solid copper clips should be used. The cheaper plated steel clips will usually self erode when submerged in the tank.

Accumulating electrode surface area relative to area being derusted governs both achievable speed and amperage, but you need to be careful because you can get the solution **** HOT.

Also remember, this process generates Hydrogen gas, so take appropriate precautions. The area immediately above the tank is a PERFECT atmosphere for a very rapidly burning fire, often called an EXPLOSION by uninformed people who are in the process of explaining to the fireman filling out the report next to the big red truck. Electrolysis breaks water down into it's 2 basic components - Hydrogen and Oxygen - and when they are recombined by ignition of the mixture, the fire burns at about 4280° Fahrenheit. Keep ALL potential sources of ignition away from the top of the tank and surrounding area.

For you speed freaks, don't even think of hooking up the DC welder to get faster results. It is possible to boil the solution, and that really sucks in a plastic tank. NO, I didn't do it and had I been the speed freak who did, I certainly wouldn't have posted that brilliant move.

Much information has been posted on the web suggesting using lye, caustic soda or drain cleaner for an electrolyte to speed up the process. This is BAD information, and the use of lye is dangerous. There is also no appreciable increase of process speed achieved using lye, so I don't see where taking the risks associated, and dealing with the HazMat created or safe disposal of caustic solution is worth
__________________
In God we trust, everyone else we shall monitor.
US Army, 1968-72. Americal Division, 196 LIB, RVN 1970

durasmack

If that doesn't work, you can obtain repair parts for most big name air tools (AirCat, IR, Campbell Hausfeld) by calling their parts and service line listed on their websites. Usually significantly cheaper than replacing them.

Also, you can get gallon jugs of hydrochloric acid from commercial swimming pool supply houses. Soaking a rust covered steel or aluminum part in hydrochloric acid for a couple minutes will remove rust. If you go that route, you must neutralize the acid and rinse them very thoroughly then oil them or they will rust again very quickly. If you use hydrochloric acid, it will give you nasty fumes so be VERY careful.

Haulin_in_Dixie

Well so far so good. A plastic pail, a battery, a charger, some baking soda, a one inch by 3/16 steel bar (all I had) for the electrode. The sleeve that the blades ride in has been in the pail for about four hours, and about half the rust buildup is gone. It does work.

After it is out I can then see how bad the pitting damage is to see if it can be used. The roter will be usable after getting the rust buildup off. Then a blade kit will put it back together again.

I am betting that there will be some pitting but that it will not interfere with the blade action. It is a 1400 ft pound CP that I need for the truck.

Clayten

Good write up very informative.

bulabula

Back in my navy days, we'd soak rusty things overnight in bug juice to clean the rust off.

Bug juice was the cherry flavored drink found on the mess decks.

Haulin_in_Dixie

Just to make it clear. I am not the author, copied it from a gun forum. I am really impressed on how it works, get rust out of all the nooks and crannys without hurting the soft parts. Does not seem to hurt the bearings or seals, bronze bushing etc. Nor does it hurt the aluminum but does take the paint off, guess it has oxyde in it.

The sleeve that the blades ride in had deep buildup of rust, would have been real hard to clean and would have disturbed the finish inside, this is taking it off and I think I can use it again, some minor pitting. Best is no labor involved, no special handling, just let it hang there in the pail. 24 hours removed most of it. And that with only the steele electrode which gets dirty after a couple of hours and stops being effective. A wire wheel brings it back to usable. Basically what you are doing is the reverse of plating, sort of plates the electrode with rust from the part you are cleaning.

Walmart has the borax sold as cleaner additive. That works better than the baking soda as the article says. Over the years I wish I had known about this method.

93w250

It works very well. I've had a 100 gal. tank going for a couple of years. I use it to de-rust/free up antique engine and tractor parts. It'll take paint off too.

Haulin_in_Dixie

I am personally a little dissappointed in myself. I am one of these people that does all his own work and well educated on it. Welding, Heliark, was a machinest for quite a while, a Ham operator for over 30 years and big into electronics. How come I never ran across it, even though I have played with plating? Now I am 66 and don't do that much any more, sure could have used it years ago.