Electrolytic rust removal

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Electrolyis and rust removal - help!

Postby gavin » Wed Jul 18, 2012 7:06 pm

P7184447 (Small).JPG
P7184447 (Small).JPG (41.66 KiB) Viewed 12217 times
My battery charger does charge flat car batteries - it works. Above is the set-up.

Here is the charger:
P7184446 (Small).JPG
P7184446 (Small).JPG (45.32 KiB) Viewed 12217 times


No matter whether I connect red or black to the sacfricial horse shoe, nothing happens.
I used 2 spoons of washing soda in warm water as electrolyte.

My best guesses are:
    1. my electrolyte is not effective
    2. the electronics are too safe in the charger and it senses the load is not ' normal'

What other comment can folk make?
How can I test the electrolyte? I don't have a current meter.
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Re: Electrolyis and rust removal - help!

Postby bulldawg_65 » Wed Jul 18, 2012 8:00 pm

Try Salt?
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Re: Electrolyis and rust removal - help!

Postby SeanHellman » Wed Jul 18, 2012 9:54 pm

How long are you leaving the saw in there? It is not quick, it takes hours. You also need more water so that the saws flat face is facing the horse shoe. Basically you are only removing rust from the back of the saw not the faces in the present set up. Remember everything travels in straight lines. It is very important you get the electrodes the right way round + to the horse shoe. - the cathode to the rusty object. In your picture you are derusting the horse shoe.
It does work very well, takes time, and you will need to turn the saw around to do the other side.
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Re: Electrolyis and rust removal - help!

Postby nic » Wed Jul 18, 2012 10:45 pm

Never tried this but I used to use washing soda to neutralise after acid etching, this caused more problems with rust than the acid etching did. My Point being that I think it would be better to remove the woodwork so you can get all the soda out.
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Re: Electrolyis and rust removal - help!

Postby SeanHellman » Wed Jul 18, 2012 11:28 pm

Good point Nic, when I do it I make sure the wooden handles are not in the solution or removed
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Re: Electrolyis and rust removal - help!

Postby gavin » Thu Jul 19, 2012 8:20 am

I now think my modern battery charger has too many fail-safes built in. There's no bubbles even after the useful suggestions above. :cry:
I'll try getting an old car battery and drawing the current from that and charge the battery from the battery charger.

Also: google ' molasses rust removal' - esp this link. No electricity - just 1 part molasses in 10 parts water - plus several days!!
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Re: Electrolytic rust removal

Postby ToneWood » Tue Nov 27, 2012 9:54 pm

HughSpencer wrote:Further work on the wonky grindstone....
Image...
Wow, that looks like a lot of tricky work - good end result. :)
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Re: Electrolytic rust removal

Postby ToneWood » Sun Feb 10, 2013 12:45 pm

I tried electrolytic cleaning last night, overnight. but it didn't work :(.
Soda bucket anode.jpg
Plastic bucket, washing soda and sacrificial anode (broken garden fork) clamped to side.
Soda bucket anode.jpg (54.38 KiB) Viewed 11853 times

I used:
- The prongs from a broken gardening fork (not vintage) as the sacrificial anode (red/+ve side) in a plastic bucket.
- I used Washing Soda (before reading Nic's warning, above) - or at least the closest thing I could find to it: Dri-pak "Soda Crystals", "...contains sodium carbonate decahydrate greater than 30%"* dissolved in tap water for the electrolyte.
- I used my trusty(?) old homemade battery charger (1A trickle charge, half cycle rectified).

When I set it up at first I saw bubbles rising from the cathode (black/-ve side) - looked promising. When I check back an hour later - no more bubbles.
Another hour later, no bubbles & I rotated the tool. This morning, no bubbles and no real sign of progress.

Electrolysis rig.jpg
Electrolytic cleaning rig with old, homemade battery charger (transformer + 1 diode). Anode dry, rusty cathode clip in electrolyte.
Electrolysis rig.jpg (52.5 KiB) Viewed 11853 times


Like Gavin, I am unsure what is wrong. However, unlike Gavin, my old battery charger has no fancy electronics, it is just a transformer & a single diode rectifier.
Some other possible factors that occur to me:

1. It was really cold last night. It looks like some of the crystals may have come out of solution as a result.
I tried adding some warm water first thing this morning to warm it up & help saturate the crystals, no improvement though.

2. Water round here is hard. It is likely that the washing soda reacted with the dissolved chalk - that's why we use it normally.
Could this be rendering the electrolyte useless/weak? I tried adding more soda crystals but no visible improvement (i.e. no bubbles).

I was thinking perhaps my 1amp trickle charger might not be up to the task but then came across this excellent article and this chap is
using a very similar setup, 1.5amp slow charger and washing soda, to good effect: http://www.instructables.com/id/Electro ... aka-Magic/

*For comparison, Arm & Hammer Washing Soda (.used by our American friends) appears to have considerably more sodium carbonate in it.
Ingredients from MSDS/Label: Sodium carbonate ~ 85%, Water ~ 15%
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Re: Electrolytic rust removal

Postby ToneWood » Sun Feb 10, 2013 1:04 pm

BTW Somebody did a test for hexavalent chromium (very nasty stuff) in the electrolyte after using stainless steel for electrodes: http://www.youtube.com/watch?v=55_j21tCN_k
According to him, his test shows that it is present, so don't use stainless steel electrodes.
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Re: Electrolytic rust removal

Postby ToneWood » Mon Feb 11, 2013 9:05 pm

I left the electrolysis running and I think there may be a small amount of progress. In hindsight, some other possible factors for lack of progress occur to me:

3. The tool is very pitted and rusted - there is a lot of rust to clean off (about two orders of magnitude more than Gavins saw!).
No. 2 Kent-style axe probably Gilpin or Whitehouse.jpg
Nice No. 2 Kent-style axe, probably by Gilpin or Whitehouse but badly rusted and pitted.
No. 2 Kent-style axe probably Gilpin or Whitehouse.jpg (163.16 KiB) Viewed 11853 times

4. The electrical contact may be poor - so I ground the edge and attached to that :)
5. My trickle charger may be only 0.5 amp (I made it in a hurry, almost 30 years ago). I'll probably order a new more powerful one (maybe 6-12 amps RMS).

I think the electrolyte is ok, it makes my skin feel soapy so it is still alkali.
There is powder in the bottom - not sure if that is undissolved washing soda or the result of it reacting (with chalk in the water or something else).
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Re: Electrolytic rust removal

Postby ToneWood » Fri Mar 01, 2013 8:10 pm

An interesting & detailed description of someones electrolysis set-up: http://myweb.tiscali.co.uk/andyspatch/rust.htm
I was surprised to read that he advocates using a relatively low current, less than 2amp and often much less (e.g. 200mA = 0.2A).
Also mentions that white powder falling out of solution is normal in hard water areas & electrolyte becoming clear is fine (both things than I noticed after a day or so).

This one also appears effective (2amp): https://www.wwgoa.com/articles/one-grea ... ctrolysis/

Both of the above use large, surrounding anodes (e.g. cut coffee-can) - might try that.

One chap here uses an old computer Power Supply Unit instead of a battery charger.
Last edited by ToneWood on Sat Mar 02, 2013 1:17 pm, edited 1 time in total.
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Mystery solved...bad electrical contact

Postby ToneWood » Fri Mar 01, 2013 8:36 pm

The above links reassured me that my basic rig is ok. There is no need for a big ampage, expensive battery charger; in fact a cheap trickle charger is probably better suited to the task.

So I just reviewed my ineffective electrolysis set-up. I hadn't previously paid any attention to the anode contact, so I wire-brushed the clean-looking anode contact point on my sacrificial anode (red/+) - a broken garden fork. When I turned the set-up back on, it burst into life, with vigorous bubbling at the tool (cathode/black/-) - deep joy :)
Image
UPDATE: This morning there was a wonderful thick brown layer of gunk floating above the tool (just as shown in the second link, above) :)
Electrolytic cleaning working.jpg
After 18 hours of cleaning.
Electrolytic cleaning working.jpg (73.65 KiB) Viewed 11853 times

[Images added to earlier post above too]

Gavin, Sean is right, your electrodes are the wrong way round in the image above & the electrodes should be facing each other. However, I wonder if one of your contacts is poor? For example, perhaps the saw has a thin layer of oil or grease protecting it. Might be worth wiping it clean with meths and/or wire wool, at least at the contact point - and wire-brush the contact on the horse-shoe. Might also be worth putting some more washing soda in electrolyte (what size spoon did you measure it with?) - apparently you can keep re-using it, it is supposed to last well.
Sacrificial anode after 36 hours.jpg
After brushing off the kelp-like gunk in the picture, there was a layer of green slime and then a layer of black powdering residue.
Sacrificial anode after 36 hours.jpg (85.6 KiB) Viewed 11851 times
Last edited by ToneWood on Tue May 19, 2015 8:18 pm, edited 1 time in total.
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Re: Electrolytic rust removal

Postby ToneWood » Wed Apr 24, 2013 8:11 pm

Update: After the above success I found the electrolytic cleaning pretty much stopped. :( I tried cleaning a couple of different tools without success. I figured I had probably blown the single diode rectifier in my battery charger. Anyway, I just bought a new Digital multimeter* - turns out:
1. my battery charger is still working fine and the connections are all good and
2. my battery charger does not have a single diode rectifier after all (it did originally), I must have upgraded it - it has a bridge rectifier (probably W005) and 2 biggish (1600uF?) electrolytic smoothing capacitors. Still simple and apparently robust (made it 29 years ago!).

So, I've started cleaning again. Wonder if the electrolyte needs replacing (apparently should be long lasting)? Update: apparently not, the electrolysis is going "great guns" again - with the electrolyte surface covered in froth [see earlier image]. I can only guess that my mains sockets are intermittently not working or my contact on the axe went bad.

BTW I've read of some folk using old "wall-wart" transformers for this too. We have quite a lot :(.

* Vici VC97 auto-ranging multimeter, £18 from ebay seller in Wales - good value I think. It functions very much like the more expensive Fluke pro tools but... Warning: be careful with mains voltages: an EE on youtube demonstrates why the mains safety ratings of non-major brand Chinese meters like these aren't genuine - refer to youtube details & for comparative reviews of its more expensive sibling, VC99 & other meters. Includes a temperature probe which might be useful too. Fab tool :).
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