Electrolysis for rust removal?

[Dodge man]

Has anyone here tried electrolysis for rust removal? It sounds effective and like a real work saver particularly in hard to reach places such as inside of frames or inside of gas tanks. There's lots of web sites on the net that talk about using it for everything from old tools to motorcycle gas tanks.

 

[Katahdin]

I've dubbed around with it, it does work. I removed the rust from a GMC trailer hitch in a 35 gallon trash can. You'll want a non-electronic battery charger or some people are using welders. I didn't have either so I was using a 12 volt jumper battery connected to a electronic battery charger. The battery charger kept getting confused.

 

[jeepin]

I did 5 combat jeep rims in a plastic tub. It works pretty well but does make a mess of rusty water, etc. I used lengths of rebar for the electrodes and I suspended the wheels from a metal chain held up by a piece of 2x4 across the top of the tub. Remember the part needs to be submerged so I am not sure how would do a frame unless you had an old swimming pool sitting around. For smaller stuff it works good.

 

[Gunfreak25]

Electrolysis works very well for removing rust, here's a post I made on the subject over at the surplusrifleforum. In fact it was so popular among surplus shooters at the board it was made a permanent information sticky. This is a small scale job, but technically if you have a wall charger that has a high enough voltage and a tub big enough the possibilities are endless as to what you could derust.

Surplusrifleforum.com • View topic - How to make and use an electrolysis tank *PICS*

 

[paulfarber]

The hardest part is the current. You are basically making a dead short, with the only resistance being water and metal (mostly the water).

You can hook up anything you want for DC power, but the current required is directionally proportional to surface area. So a low current and a large object means you will be waiting a while. The conversion is also 'line of sight' from the cathode.. so it you have rust INSIDE a tube or frame, to really get it you will need to rig up a cathode so it has a straight path to it... without shorting the current and making your power supply go boom.

The largest object I did were some handles for my CCKW. I used a DC power source with overload protection and it took about a day.

If you have flaking rust, make sure you brush it off.. you still also need to brush off any large chunks of converted rust post conversion.. otherwise it will simply fall off and take any paint you have with it.

For a frame I would look up a dip shop. They generally charge per pound and can get all the rust everywhere... even phosphate the steel post dip. It might take a day or so but as stated, by the time you rig up a vessel, and get a DC power source large enough to actually be useful you could have it dipped and done.

 

[Dodge man]

Power is NO problem here! I have a number of lab grade power supplies (mostly HPs) that range up to several thousand volts and several hundred amps (not both at the same time!). Nearly all have Constant Voltage, Constant Current or Constant Power regulation. (I LOVE these things and I use them all the time. I buy them surplus for next to nothing!) If I need bigger I have a 300 amp Miller welder! I just hooked up an electrolysis tank today and I have one of the M37 bed stakes 'cooking' now. I had an old water softener tank that I cut down and used so it's big enough to hold nearly anything except an engine block or complete frame.

PS my power supplies don't go boom. I always set the current and voltage limiting on them!

re:Straight shot to the rusted area. That's not difficult, they handle situations that in plating shops all the time. You just need multiple anodes and arrange them facing areas that need the most de-rusting. They even do varying thicknesses of plating by intentionally shading some areas so that they get less plating.

 

[paulfarber]

Stake pocket? That seems like a waste for something as non-critical as a stake pocket. Sandblast that and be done in two minutes. Electrolytic rust removal is more for very odd or delicate parts that would not hold up well to grit blasting. Way to much work for sheet metal. You will still have to scrub and prep the part post electrolysis.

Sandblast it, sit it in phosphoric acid for a few minutes to get a phosphate coating, rinse, dry, and either let sit for batch painting or assembly.

 

[Gunfreak25]

I agree. Unlike vehicle parts, I have only ever used electrolysis on firearms where we want to retain as much of the original metal finish as possible whilst also removing as much rust as posible. Wouldn't make much sence to use electrolysis on a truck part, only to sandblast it later in prep for painting.

 

[wdbtchr]

I need to clean the rust from inside a motorcycle gas tank for my son(soldier #3). The outside is good not so much for inside. I put in about 4 cups of pea gravel and bungee corded it to the center of a tractor wheel while mowing for a couple of hours(think rock tumbler). That took out most of the worst rust. Thinking of using electrolysis to get the rest. I'm thinking using a bent piece of rebar inserted through the gas filler and insulated from the metal with pieces of plexi-glass for the anode and attaching the other lead to the tank itself, then filling it with the electrolyte. Anyone ever done just the inside of a fuel tank?

 

[m16ty]

I've done the electrolysis before and it does work. I've been thinking of doing the same with some old Jerry cans I've got. I don't see any reason why it won't work.

 

[Fredo Corleone]

Do this in a very ventilated area as it can produce hydrogen gas. I know this because last month I responded with the Fire Dept. to a carbon monoxide alarm at a condo where the owner was cleaning cast iron frying pans with electrolysis. I found out hydrogen gas will give off a false positive for CO and cause detectors to go off.