[ball]

I read somewhere about this rust removal process using electrolysis a few years ago.

I purchased some washing soda as the instructions called for and then put it on my shelf to be forgotten about.

I am in the process of cleaning up the workshop at the moment and I found the little bag of powder so I figured I would pull my finger out and have a crack.

Basically you need a plastic tub, some washing soda (available from woolies for about $5 a KG), some water and a 12vdc power source (battery charger), and a piece of steel to use as an anode.

I mixed up the washing soda into water at around 10-15 grams per litre.

The + lead on the battery charger goes to a piece of scrap steel and the negative lead goes to the part you want to remove the rust from.

Make sure the leads don't touch the water solution and make very sure that the part doesn't touch the anode.

Here are some pics.
This is the basic setup.



You can see the high tide mark quite clearly in the next pic. This head has sat outside for about 3 years now and is quite heavily rusted. This is the result of about 4 hours bubbling away. I didn't scrub the rust with anything at all. Just hit it with the fire hose.



Now for a bit of safety. I am pretty sure that the bubbles given off will be hydrogen and oxygen. If anyone tries this make sure there is plenty of ventilation and no ignition source. Make sure the battery charger is turned of before connecting or disconnecting the leads as you will get sparks when you do this.

[shep]

can ya make a tub to fit a lwb sierra?

[whincup]

we did something similar back in year 12 at school in chemistry. using just table salt and water, we mixed in as much salt as we could, then ran a 12v power source through the water for about half an hour. ended up with a pH reading of around 13, making the alkalinity the equivalent of straight bleach. so this doesn't suprise me at all. very interesting results...

[ball]

I can't see salt being a decent substance to use. It would probably work as I think you only need an electrolyte but steel tends to rust pretty quick in salty water.

[ball]

shep wrote:

can ya make a tub to fit a lwb sierra?

Make a kids style swimming pool with thick plastic to sit the whole thing in.

Would need more than a $50 battery charger though.

[whincup]

ball wrote:

I can't see salt being a decent substance to use. It would probably work as I think you only need an electrolyte but steel tends to rust pretty quick in salty water.

wasnt really meaning use salt, just saying that i've seen proof that electricity can cause crap diluted in water to have a high alkaline level. pretty sure the soaking in a salt bath would quickly undo that 4 hours pretty quickly...

[matty_wall]

Its a REDOX reaction; pH has little to do with it

[rustyzook]

leave it in there for a few days

[ball]

rustyzook wrote:

leave it in there for a few days

That's the plan

I am going to add more anodes and maybe more power and see if I can crank it up.

[PJ.zook]

Or you could just soak it in phosphoric acid

[ball]

Phosphoric acid will turn rust black.

It is more a rust converter than remover. Turns iron oxide to ferric phosphate (I think, been a few years since chemistry class)

I am aiming to remove rust without discolouring the base metal.

I have phosphoric acid and it doesn't do what I want.

[matty_wall]

ball wrote:

Phosphoric acid will turn rust black.

It is more a rust converter than remover. Turns iron oxide to ferric phosphate (I think, been a few years since chemistry class)

I am aiming to remove rust without discolouring the base metal.

I have phosphoric acid and it doesn't do what I want.

Correct.. it creates a air tight layer to stop further rust occurring.

[alien]

this is cool =)

something like a neon transformer would likely do a great job of it in no time at all! hahaha i scored a neon transformer years ago from a sign place and made a "jacob's ladder" out of it with copper wire - had a MASSIVE green flame between the wires... great fun. lol

[ball]

alien wrote:

this is cool =)

something like a neon transformer would likely do a great job of it in no time at all! hahaha i scored a neon transformer years ago from a sign place and made a "jacob's ladder" out of it with copper wire - had a MASSIVE green flame between the wires... great fun. lol

I have an old ac welder that I am going to rip the transformer out off. I just have to find some big diodes and a monster capacitor now.

[alien]

make sure you run it on a powerpoint connected to the house's RCD just in case =) lol

[rustyzook]

commo v6 coil with a few bits and run off a battery charger. jacar has a kit i think but a neon trannie! that would be sick!

what kinda metal are you using as the "scrap"?

interesting thing with this, you can copper plate steal and such by using different metals and changing polarity and such.

[ball]

I started with a piece of reo bar. When I threw the head in I used a piece of 25x25x3 mild steel angle. The angle with more surface area definitely hurried things up a bit more.

I am looking to do some aluminium anodising next

[rustyzook]

nice, was the mild steal clean or rusty to?

[ball]

was clean, now rusty.

A quick hit with the disc sander and it's good to go again.

[rustyzook]

haha yeah, electrolysis is a funny thing! hows it coming along? pics? i may try this one day.
still on 12v?

[shep]

Is that forklift charger thing still avalable? It was 36 volt and 150 amp
That would do a car

[rustyzook]

haha yeah

[zukenutter]

Very cool ball

[jdk81]

Have you considered tacking a whole heap of scrap steel together in random orientations to increase surface area of the anode?

[ball]

The next step is to put multiple anodes around the tub.

I think the current draw will be to much for the small battery charger if I get too carried away.

Just stepping up to angle from the reo caused the current to go from 2 amps to 6 amps.

[missmyljdaze]

I have used a smaller scale version to remove copper and lead built up in rifle barrels, you have to be very carefull or you can burn holes in the barrel steel if not done correctly.

[ainzy]

A much slower but far more friendly version is to use mollasas and water mixed 6parts water to 1part mollasas takes about a week even on heavy rust buz cleans it up beautifully its on you tube . Sorry sbout the hijack

[ball]

I have read that the molasses method will eventually attack the parent metal. I have also heard it stinks bad.

[rustyzook]

hows it going?

[ball]

I haven't put it back in yet. Hopefully today.