I found the method a while ago on the net but didn't have the guts or need to try it.

http://www.stovebolt.com/techtips/rust/electrolytic_derusting.htm

My first try:
Old black plastic bucket and a horseshoe as positive electrode.

Attached the positive pole from the battery charger by a earthing wire to the horshoe(it will be consumed in the process)

A gallon of water and 1 tablespoon of soda.

Then attached the negative by a pipe clamp and a wire to the to be tested scrap headerpipe(mt500)

(you must make sure the soda/liquid makes the contact and not the metal electrodes, so isolate the two from eachother by a plasctic grid(paint diffuser grid) or some thin blocks of non conductive material: wood/plastic/rubber) The closer the two objects are the better the current passes through the liquid and the faster the process.

Power on:
The process starts and you'll see small bubbles coming from the the to be derusted in this case the headerpipe. After an hour or two the more supperfucial rust has come off. Maybe the deeper rusty places are still a bit rusty. The after work could be to brush or sandpaper the more troubled spots. Or to lengthen the derusing time in the bath.

Still its a lot less work, a neater finish and less or not damaging to the non rusted metal bits.


I would see read the manual
(http://www.stovebolt.com/techtips/rust/electrolytic_derusting.htm) yourself and test it.

!!!DO NOT CONNECT THE POSITIVE TO THE TO BE DERUSTED PART IT WILL BE CONSUMED!!!

Good luck.

(please test it on a testing piece first)

kenny

What kind of soda do you use?

Stewart

Well its the kind that says" for 101 uses" translated from dutch. I think its the simpelest cleaning product. Feels like a slippery sugar salt combination.

My wife uses it in the kitchen, "SODA" is a commen good in holland for cleaning.

Giving you a brand name would not be sufficient i think, in Great Brittain the brand name would be different. Butt i will take a look later on.

PS:
Also good when you want to ease out a splinter in your skin, therefore soak the body part in warm water with soda.

Stewart,
have a look at the link, washing soda or baking soda are both mentioned
Eric

normal washing soda.

BUT

this doesn't really work, it converts rather then removes rust. I tried it and its both messy and dangerous and doesn't give good results. Plus you need some way of limiting the current to avoid over heating your power supply.


A much better method is using the acid commonly used to balance the Ph of swimming pools. Now this really does work, completely removing the rust. Best of all you can completely derust the inside of a steel fuel tank without damaging the paint or using bolts inside the tank to loosen the rust.

You can buy this as 'deox-c' and does not require an electric supply to work. Just add water and dip the rusted item it it.

http://www.bilthamber.com/deoxc.html


a 1kg tub does 20l of water about £12

Pete

The comment about converting rather than removing rust is valid offcourse.

In my case most of the surface rust eventually floated in the bath, and the rest was like a black powder easily brushed or sanded away with a light abrasive cleaning pad.

Leaving a clean metal finish.

Does the swimming pool stuff affect the bare metal or only the rusty parts?

ps

I'm also using a solar battery charger with electonics, which probably control the current and thereby prevent the setup from overheating.

At least untill now.

It might do, but the battery charger is seeing a virtual short, so its best to put a bulb in series. The bigger the item the more current you need. Something like a fuel tank needs 1-2 amps and a whole frame is getting near 20. I've seen welders been used to give 80-90 amps for really big items.

I burnt out 2 standard car battery chargers doing this and I wasn't impressed with the amount of work still to do after the items have been in the bath. The acid method leaves the metal clean ready to paint. It only works on bare metal/rust, paint will mask the surface. This is applicable to both methods though.

Never tried this method of rust removal, so I don't know how effective it is at the side of blasting, might give it a try sometime.
I built myself a simple blast cabinet but its a rather expensive process especially when you are using aggresive blasting media like sand it wears the gear out quickly, glass is more gentle and does not remove the good material. --------- Chris

ive never used that way but i do use a pound of black treacle in a gallon of water i takes about a month and no electrickery involved but it cleans up the rust