Electrolytic Rust Removal

[Kat Manton]

Hi,

Although I've not tried this technique on a rusty steel radio chassis, I thought it'd be worth mentioning here.

A Google search for 'electrolytic rust removal' brings up plenty of information so I'll just link to two sites:

• http://myweb.tiscali.co.uk/andyspatch/rust.htm
• http://www.davidbradley.net/ERR.html

My setup:

• Power source: Car battery charger with switchable 'LO/HI' and '6V/12V'.
• Container: Plastic washing-up bowl or large plastic bucket, depending on what I'm derusting.
• Support: A grille from an old refrigerator, used with bits of MIG welding wire for suspending parts in the electrolyte.
• Electrolyte: Washing soda crystals from the local supermarket.
• Sacrificial anode: bits of old steel brake pipe with the paint sanded off.

I find the best results are achieved doing this slowly, overnight (in the garage); I set the charger to '6V' and 'LO'. Once derusted I give the parts a quick clean-up in the kitchen sink with a Brillo pad, very little 'elbow grease' is involved overall for very impressive results. Even any remaining traces of paint come off.

Attached are 'before and after' pics showing the results obtained using this technique on the pan-ring of one of my pressure stoves (a Valor 51, for any 'stovies' among us. Yes, I collect pressure stoves... )

Cheers, Kat

P.S., If anyone feels inclined to discuss pressure stoves, feel free to PM me rather than take this thread OT

[GMB]

Although I have not tried this I once saw a demo of another aspect of rusting. Once you have you nice clean item it is less likely to rerust if you leave it to soak in very clean water which has had the air boiled out of it. It may even help to boil the metal in water.

The point is that rusting occurs because of tiny pockets trapping salts which form tiny electro-rusting cells on the surface of the metal. So if you can wash away this surface-trapped salt then it is much less likely to rust.

I should point out that when I saw this demonstrated the effect of leaving the steel in the clean water was to form a certain quantity of superficial rust (which just washed off) but after this treatment it rusted less fast than the original material.

[Mike Phelan]

In the chemistry lab at my school, centuries ago, three bottles were used with some iron filings in them:
One just had tap water, one had nothing else in it, the last one had boiled and distilled water full to the top.
They were left for a couple of weeks, and only the first one rusted.
Conclusion - you need both water and air to rust iron.

[Al (astral highway)]

Hi Kat,

Thanks for this info. Can I share a similar experience, but with a twist?
The chassis is steel but copper coated! This makes it much trickier and in fact I've had quite an interesting time...!

The original copper coating (dated 1940) had begun to rust, meaning that there were 'open' areas in the chassis. In other words, the copper coating was somewhat 'porous', for want of a better word.

The first picture shows the effect of full-blown electrolysis on a damaged area, followed by treatment immediately with 'exit rust', which converts the rust to magnatite, I think. It's not very clear from the picture, but in fact, a beautiful salmon-pink copper coating did develop on one or two patches of the sub-assembly here, where the surface was not damaged.


The second picture shows what I started with! The damage I unwittingly caused is not as alarming as you might think, as I have only tested a tiny part of the overall job in hand and will obviously be changing my methods!