# Will electrolysis damage bearing housing during rust removal?



## RGIvy (25 Nov 2020)

I'm about to strip my spindle down on my Fiat Ducat motorhome.
I'm planning to get rid of the rust and prep for paint before I reassemble with new bearings.

My question is: if I use electrolysis to remove the rust (washing soda with 12v battery charger), is there a possibility of damaging the bearing housing?
(I understand some of the theory of electrolysis but never actually done it)


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## MikeK (25 Nov 2020)

Is there a reason you don't want to have it bead blasted instead of using electrolysis? I can't imagine that electrolysis would be faster or easier, unless there is no place to do the blasting.


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## RGIvy (25 Nov 2020)

MikeK said:


> Is there a reason you don't want to have it bead blasted instead of using electrolysis? I can't imagine that electrolysis would be faster or easier, unless there is no place to do the blasting.


I actually have a sand blaster and plenty of space, just thought to do something different and fun. I'm not in a rush, so would prefer a better finish than doing it fast (or even easier).


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## HappyHacker (25 Nov 2020)

Electrolysis done properly should not damage un-rusted steel. I have used it on a saw blade and the engraving of the name was still ok.


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## Jelly (25 Nov 2020)

HappyHacker said:


> Electrolysis done properly should not damage un-rusted steel. I have used it on a saw blade and the engraving of the name was still ok.



Exactly, at normal power levels, the risk of damage only starts to creep in if there's severe contamination with metal ions in the electrolyte, an excessively high or low pH or a dissimilar metal is used as the electrode.

I would however note that applying greater than normal potentials (voltages) or overall power levels (wattages) to a cell, to speed things up could fundimentally alter the electrochemical processes and cause things to go wrong even if everything else is set up correctly.


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## Rorschach (25 Nov 2020)

It is possible and I wouldn't risk it myself on a critical item.

Coating the bearing surfaces with thick grease might provide a good barrier though personally I would go with a different method. Sandblasting as mentioned above would be an excellent choice.


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## Inspector (25 Nov 2020)

When you sandblast are you masking the bearing surfaces to keep them from being eroded? Or are you building them up by welding or plating and machining back to size again? Electrolysis only removes the rust unless you leave it in for a long time. 

Do a test on something that doesn't matter. Get some rusty rebar and machine part of it to clean metal and a size you can measure and remember (or write it down). Toss it in the electrolysis tank and when the rust removal is done measure the machined area and see how it compares to the before number. That will give you an answer and remove all doubt.

Pete


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## RGIvy (25 Nov 2020)

Inspector said:


> When you sandblast are you masking the bearing surfaces to keep them from being eroded? Or are you building them up by welding or plating and machining back to size again? Electrolysis only removes the rust unless you leave it in for a long time.


If I sandblast I'll simply avoid machined surfaces and clean around them with a brush instead. Perhaps I'll also plug them up with something.



Inspector said:


> Do a test on something that doesn't matter. Get some rusty rebar and machine part of it to clean metal and a size you can measure and remember (or write it down). Toss it in the electrolysis tank and when the rust removal is done measure the machined area and see how it compares to the before number. That will give you an answer and remove all doubt.


I was planning on doing this anyway. If everything goes very wrong a new spindle is not that cheap but won't totally break the bank either.


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## Sandyn (25 Nov 2020)

If you want to try it for fun, have a go. It's pretty easy. I just did a block and chain using electrolysis and posted some pictures on here somewhere, It worked very well, but if I had a sandblaster I would have used that and got a better finish, I think. There's a lot of mess with electrolysis' but I did save the hydrogen I produced for when I get a new car!


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## AES (25 Nov 2020)

I don't KNOW this (haven't used the electro method on anything that "matters") but I GUESS that if the face of the bearing housing is also rusty, then the electrolyte will "attack" that rust like any other rust elsewhere on the part.

Note however that not knowing the tolerance/s on that bearing housing, if it IS rusty inside the housing there's a good chance that the whole part is scrap anyway - i.e. a correct spec new bearing would be too loose a fit in the housing. Do you have a Manual? How is the bearing removed replaced? Puller? Heat/Cold?

But note also, even using the softest media in a sand-blaster, you could well bring the housing out of tolerance anyway (rusty or not) unless the housing area is well masked.

Suggest before going further you consult a Manual, or perhaps, a friendly local garage for a bit of info on the tolerance/s.


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## wallace (27 Nov 2020)

If the part is cast iron you could leave it in the electrolysis tank indefinately it will come to no harm. If the part is steel then you cant, and you must keep checking it.


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## RGIvy (27 Nov 2020)

I did some testing and it worked well. Put my brake caliper carrier in and it's cleared pretty well. I'll post photos of before and after when I've finished cleaning and painting.


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## RGIvy (3 Dec 2020)

Completed first carrier. Left on electrolysis for about four hours, washed and hand-brushed. Painted with red oxide.


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## AES (3 Dec 2020)

Looks good, well done. I guess quite a few quid saved in return for "just" a few hours spent.


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## RGIvy (4 Dec 2020)

AES said:


> Looks good, well done. I guess quite a few quid saved in return for "just" a few hours spent.


I had originally thought to buy new carriers but found they cost about £115 each!


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## AES (4 Dec 2020)

Blimey! Guess you must be running a vintage Rolls-Royce or summat! Yeah, surprising how much can be saved sometimes, innit??


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## RGIvy (4 Dec 2020)

AES said:


> Blimey! Guess you must be running a vintage Rolls-Royce or summat! Yeah, surprising how much can be saved sometimes, innit??


If by "vintage Rolls-Royce" you mean a 1994 FIAT Ducato then yes.
I couldn't believe how expensive they are. Don't appear to be overly complicated. Rusted quite a bit so not particularly special metal. Having said that once all the surface rust removed they appear to be fine.
And yes, saved quite a bit by cleaning existing carriers - done in my spare time.


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