Post electrolysis treatment?

[julianf]

This steel rim has been in electrolysis for weeks (I've been in no hurry)

It was painted prior. The electrolyte used was KOH, which has stripped the paint nicely also.

(Id run out of NaOH)

It still has brown in the pitting, which I know isnt exactly attached, but is on the surface.

I was not able to pressure wash it when I took it out as it was late, and I think this is the reason it's not cleaner.

I suspect wetting it and washing it now probably won't do anything.


Im considering 3 options -

Back into the electrolysis for a day or so and then pressure wash.

Or

Acid, then pressure wash, then redip in caustic to neutralize

Or

Scotch



The job is, basically, there. But I'm wondering how to finish it up best.

What would you do?

 

[Ross365]

I'd definitely go down the well-troden path of citric acid . I've never been a fan of elelctrolysis, least of all for a shape as irregular of a car wheel.

 

[tom2207]

Id just send it for media blasting ,,, then prime and paint it ,,,

 

[sako243]

If it's just a one off whizz around it with a wire wheel or some WD40 and scotch brite pad.

I had a live centre that was worse than that. Just chucked it up in the lathe and some WD40 and scotch brite pad around it very quickly cleaned it up.

 

[Ross365]

If it's just a one off whizz around it with a wire wheel or some WD40 and scotch brite pad.

I had a live centre that was worse than that. Just chucked it up in the lathe and some WD40 and scotch brite pad around it very quickly cleaned it up.

WD40 before painting???

 

[julianf]

I'd definitely go down the well-troden path of citric acid . I've never been a fan of elelctrolysis, least of all for a shape as irregular of a car wheel.

I don't understand it, but it's a myth that it's line of sight only. Again, I can't argue the physics as I only know from experience.

I like it as you can forget about it and it will never go too far.

I also like it as it will strip paint etc also.


But it's not either or. In this very instance im suggesting using both!

 

[sako243]

WD40 before painting???

With a scotch brite pad and some elbow grease, I've found it works very well at removing rust deposits. Will clean off easily with brake cleaner, which should be done anyway before painting.

 

[MattF]

Any of your options should work.

 

[Ross365]

I don't understand it, but it's a myth that it's line of sight only. Again, I can't argue the physics as I only know from experience.

I have tried it, but was not impressed, but I was looking for a quick result. What do you use as the anode material?

As your experience says that it does not depend on line of sight, I wonder how a control test, using hydroxide only and with no applied current would work? I wonder if the current just induces convection in the solution, in effect, stirring it?

 

[MattF]

I have tried it, but was not impressed, but I was looking for a quick result. What do you use as the anode material?

As your experience says that it does not depend on line of sight, I wonder how a control test, using hydroxide only and with no applied current would work? I wonder if the current just induces convection in the solution, in effect, stirring it?

I agree with @julianf in that it's not line of sight. Does it make the process work more quickly if you have multiple anodes in relation to all surfaces: Yes. Is it necessity: No.

Cast iron is what I use nowadays, as the anode.

Without any current, all it will do is retard/halt rusting, & remove paint. The rust would remain.

With regard to your stirring point, it does. You can see the effect in motion when the process is running.

 

[Ross365]

Seems as if the bottom line is simply that the chemistry that goes on is not greatly dependent on the current density.

 

[MattF]

I uploaded a somewhat indepth pdf on here the other week, regarding its use in conservation. That may be worth a read.

Edit: This post.

Post in thread 'Record vice’s'

Nov 6, 2025

This is the pdf. The electrolysis sections are towards the end of the file.

• MattF

• 

 

[roofman]

This steel rim has been in electrolysis for weeks (I've been in no hurry)

View attachment 520068


It was painted prior. The electrolyte used was KOH, which has stripped the paint nicely also.

(Id run out of NaOH)

It still has brown in the pitting, which I know isnt exactly attached, but is on the surface.

I was not able to pressure wash it when I took it out as it was late, and I think this is the reason it's not cleaner.

I suspect wetting it and washing it now probably won't do anything.


Im considering 3 options -

Back into the electrolysis for a day or so and then pressure wash.

Or

Acid, then pressure wash, then redip in caustic to neutralize

Or

Scotch



The job is, basically, there. But I'm wondering how to finish it up best.

What would you do?

just done 4 vivaro steels myself..good stiff wire wheel on a 125mm grinder...5 mins wheel looks new, but your kite wont

 

[Ross365]

I uploaded a somewhat indepth pdf on here the other week, regarding it's use in conservation. That may be worth a read.

Thanks for that. I wouldn't be surprised if there are a load of people who have written PhD theses about rust and rust removal, and the details about why electrolysis (in this context) is not line of sight has been figured out.

 

[Kram]

Citric gives some protection in my experience. I've got bits of steel that have lived outside since 2020 or earlier that took a long time to surface rust and not yet worth bothering to treat.

 

[julianf]

Citric gives some protection in my experience. I've got bits of steel that have lived outside since 2020 or earlier that took a long time to surface rust and not yet worth bothering to treat.

You seem to have a handle on pricing often. Someone posted this some time back -

Wholefood Earth - Citric Acid 3kg - Anhydrous - Food Grade : Amazon.co.uk: Grocery

Free delivery and returns on all eligible orders. Shop Wholefood Earth - Citric Acid 3kg - Anhydrous - Food Grade.

www.amazon.co.uk

3kg for £9

Is that still the sort of deal to go for?

Ill need to fill the bottom 1/4 or 1/3 of a plastic barrel. So 50-60ltrs of solution needed.

 

[Onoff]

You seem to have a handle on pricing often. Someone posted this some time back -

Wholefood Earth - Citric Acid 3kg - Anhydrous - Food Grade : Amazon.co.uk: Grocery

Free delivery and returns on all eligible orders. Shop Wholefood Earth - Citric Acid 3kg - Anhydrous - Food Grade.

www.amazon.co.uk

3kg for £9

Is that still the sort of deal to go for?

Ill need to fill the bottom 1/4 or 1/3 of a plastic barrel. So 50-60ltrs of solution needed.

You can drop a water filled bucket into the well of the wheel to displace and reduce the 50/60 litres.

 

[Tom O]

I thought her moustache was coming back.

 

[Misterg]

You seem to have a handle on pricing often. Someone posted this some time back -

Wholefood Earth - Citric Acid 3kg - Anhydrous - Food Grade : Amazon.co.uk: Grocery

Free delivery and returns on all eligible orders. Shop Wholefood Earth - Citric Acid 3kg - Anhydrous - Food Grade.

www.amazon.co.uk

3kg for £9

Is that still the sort of deal to go for?

Ill need to fill the bottom 1/4 or 1/3 of a plastic barrel. So 50-60ltrs of solution needed.

£2.39/kg here (2kg bag)

https://www.amazon.co.uk/dp/B08QSD3NBR

The super-duper evap-O-rust replacement still works at half strength (so 50g / litre of citric acid + 20g / litre washing soda OR 15g / litre of caustic soda) = 2.5kg of citric acid + 1kg of washing soda OR 750g of caustic soda to make 50L of 1/2 strength solution. Stuff can be left in it for pretty much as long as you like without ill effect.

Normally citric acid on its own is used at a lower concentration - probably half the above, or less.

 

[julianf]

If you get your hands in the solution made with caustic, do they feel soapy, like the do if you get plain caustic soda on them?

(Saponification of the fats in your skin)