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Electrolytic Derusting


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So i've made a start on rebuilding the front axle on the 90, and decided it would be rude to refit the rusty hubs and swivel housings, so after chatting with a mate decided to give the electrolytic method of derusting a go.

If you havent heard of it before, you basically use electricity to reverse the rusting process. It sits in the bath for many hours, and when you remove it, the rust just rubs off! No grinders or hours with a wire brush! So i've got a plastic container, which is filled with water, and made alkali using washing soda (sodium carbonate). You then place some sacraficial steel plates round the edges of the container, connected to the positive terminal, and the workpiece sits in the middle connected to the negative terminal. (Dont get that wrong, or your workpiece will disintegrate!)

A pic of my bucket:


Ideally i'd be using fresh steel plate, or rebar, but i dont have any, so i just chucked in the old brake disk mud shields from the rear axle, and some other bits of scrap metal, not ideal, but works well enough.

You require a 12v powersupply, capable of delivering a few amps. A battery charger is the usual culprit, however mine is an "intelligent" thing:


So i put a battery in between the charger and the bath, this way the charger is happy and supplys power as it sees a battery, and as long as the chargers output is higher than the draw, the battery doesnt get discharged/damaged:


I put a fuse in the feed wire, as theres obviously a chance things could short out inside the bucket, and unlike a battery charger, the battery isnt going to just cut out. It seems to draw around 2.5A, and the charger can output 3.5A, so its fine.

I'll post some "after" pics once its been in there a while, it will need a good 24hours in there, perhaps longer, and the workpiece will probably need turned a bit, as the process is very line of sight, and my anodes arent ideal.

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Hello,Ive used the same method.It takes alot of the grunt work out of cleaning parts.

Ive got some good results from this.I have left badly corroded parts in this solution for a week and taken out rust free parts.Its good for all those nooks and crannies you cant sand.post-15682-126874830363_thumb.jpg

This is what the sacraficial anode looks like after a week.post-15682-126874857599_thumb.jpgpost-15682-126874863523_thumb.jpg

Cleaned part drying.post-15682-126874873469_thumb.jpg

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that's a cracking idea. now all i need is a swimming pool to drop the disco in :) and a nice large generator, could use some crappy euro box as the sacrificial steel :) :)

You want to be able to report it as stolen I guess? ;)

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Well impressed, I'm currently building a Landy Hybrid so I bought (sorry about the "B" word) a simple kit off Ebay for about £15 + P&P, and again does the same job as yours. It also had some good info with it when wanting to do small items. I'm going to employ the "home-made" version with the bigger items, but not to swimming pool size, ha ha :D

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Okies, bit of an update!

Bucket ends up looking something like this:


This part has been in probably for a day and a half all in (with a few turns and a couple of quick once overs with the brush just to get even coverage), bit of very mild wire brushing and it comes out like this:



One slight issue is that the component tends to flash rust very quickly when removed and dried. I'm probably going to give it a coat of paint, but to stop it rusting just now, i've given it a good coating of WD40.

Its quite amazing the detail that reappears after this process. There was no sign whatsoever of the date stamp before the process, where its now clearly visible.

I'm impressed, and will be putting the hubs etc thru the process too before the axle goes back together. If i'm feeling adventurous, i might even try doing an entire axle case!

I'll put up some more photos as i get the bits done!

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Ye, i was thinking of doing an end at a time, using a big water barrel or similar.

Only problem is the front axle is already painted, and i dunno if i can be bothered redoing it, and the rear axle is a salisbury, so not particularly easy to remove the diff from the case.

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