Thread: more rust removal

Originally Posted by BobL

Molasses works a rust remover because it also contains a mixture of weak organic acids

I'm no chemist but from what I've read, molasses removes rust by chelation not by its weak acidity.

Chelation is the binding of metals by an organic compound by the sharing of electron pairs.
The molecule latches on to free Fe II on the surface of the metal.
The molecule does not have sufficient strength to break iron-to-iron or in un-rusted steel; hence it is self-limiting and non-corrosive. The process is NOT based on the action of EDTA, citric acid, glycolic acid, or their sodium salts.

Anyone who is interested can google to their hearts content, but for my money molasses is an effective, safe and cheep rust remover.

Hey Morrisman,

I've has good results using the battery charger method ................. worth a look if you are considering options.

For big things use a big wheelie bin instead of a small 9 litre bucket.

Here is one version - zillions of pages if you google for it.

http://www.fergusonenthusiasts.com/r...%20Charger.pdf

The washing soda is cheap and easily available at a woolworths supermarket in the laundry section.

Australian Wood Review had an article about it several years ago - so you might already have it.


Bill

Be very wary of cast iron soaked in molasses for a couple of weeks. It can remove more than just rust .

I had the unfortunate experience of soaking a broken exhaust manifold from a Dodge fire engine in the stuff. It was ruined.

After a few weeks immersion the molasses mix may remove more than just rust, but also the interstitial carbon leaving the cast iron with a sponge like appearance. I can't say it was exactly that, but it seems the most likely outcome.

Not something you may wish to chance your lathe bedway or cross or compound slides in.

<edit> I went backt o google and found a pic from a model t forum of a manifold ,pitted after immersion in the molasses mix- see below.

Grahame

I think from memory Ueee used electrolysis when cleaning up his Antrac lathe. I have used this method using washing soda as the electrolyte and I found it to be a good method for general cleanup and paint removal. I did not notice and metal removal BUT it's very important to get the polarity right otherwise your part will slowly dissolve!

Simon

The molasses does an excellent job, I'll have to remember that one.
For now though, I have a couple of dumb battery chargers I was going to throw out, one is 8 amp the other 10, will they suffice,or do I need more/less amps?

Originally Posted by emanon

The molasses does an excellent job, I'll have to remember that one.
For now though, I have a couple of dumb battery chargers I was going to throw out, one is 8 amp the other 10, will they suffice,or do I need more/less amps?

That should be plenty. I have only done it a couple of times. I stired in the washing soda until I got a current of about 2 amps (from memory) It's all a bit of trial and error but it's around about that sort of current.

Do it out in the open, it produces hydrogen gas. Not at a high enough rate to catch fire but if it were to build up through lack of ventillation then that's another matter.

Last week I went to a fire where some old dude decided to cut open an automotive LPG tank. The lovely man wanted to cut it in half to make a planter box for his veggies. Unfortunately for him, after he opened the valve to let any excess gas out, it found the pilot light from his water heater all too irresistible.

Lets just say that when we got there, the backyard was on fire, his shed was on fire and the back fence was also on fire. Luckily he was uninjured. His wife was very, very unimpressed!

Cheers,

Simon

Washing soda, not familiar with that, is that like Omo?

Originally Posted by emanon

Washing soda, not familiar with that, is that like Omo?

Short answer is No, but Omo would possibly still work to remove rust. Washing soda is generally sold in supermarkets with other household chemicals, like household ammonia, caustic soda, borax, metho etc, but also can be in the laundry products area or even in the bathroom products area with soaps etc. There it will be sold as bath salts, 'Lectric soda is one well known brand, and there will be others, some perfumed, but just plain works as well as anything. Sometimes I have seen it in large lump form where it appears like transparent crystals, but if ground it appears white like glass would if ground up fine. It is cheap and safe to use, and has no issues with its disposal after use. It works well and while Hydrogen is certainly given off, it is a gas much lighter than air, and will dissipate in any ordinary shed, and in most buildings for that matter. A sealed shipping container might be different, but in the quantities generated, unless some effort was made to trap it, the hydrogen will escape without becoming an explosive hazard.

Washing soda
It looks like rough crystals, the same colour as sugar, and was available at the supermarkets ,a few years back.
Cleaned up a saw frame that had been underwater in the floods and used an 8 amp battery charger.. Apparently the stainless steel anode I used was a no no as it gave off some nasty gas that was carcinogenic.

The rust ,though was completely removed but I have forgotten the time span it took.

Hope this helps,
Grahame

Originally Posted by Ropetangler

it is a gas much lighter than air, and will dissipate in any ordinary shed, and in most buildings for that matter. A sealed shipping container might be different, but in the quantities generated, unless some effort was made to trap it, the hydrogen will escape without becoming an explosive hazard.

That's a good point and one that I failed to mention!

Simon

Originally Posted by Grahame Collins

The rust ,though was completely removed but I have forgotten the time span it took.

Hope this helps,
Grahame

The washing soda can be bought at Safeway/Woolworths and probably coles. If you can't find it just ask for washing soda. They will actually know what you mean. In terms of timeframe, I have left it going for 12 -24 hours with a current of about 2 amps. Just make sure you get the polarity correct. I can't remember which way round but if you get it wrong, it will corrode your part away instead of clean it.

Simon

Washing soda - sodium carbonate - can also be purchased in larger quantities from the pool section of Woolies, where it is sold to increase the ph level of pools.

You can also make your own by heating baking powder (sodium bicarbonate) in the oven at about 150 degrees for an hour or two. (or you can just use the sodium bicarbonate, as it'll do the same job, it's just not as good a mild grease remover).

And the problem with using a stainless steel electrode is that the process pulls the chromium from the stainless, leaving you with a solution containing hexavalent chromium, which is both poisonous and carcinogenic. As the solution bubbles, the chromium nasties can be aerosolised in the mist, so it's not something you want to breathe in.

If you use table salt - sodium chloride - instead of sodium carbonate then you'll get chlorine gas given off at the electrode, too, but at least chlorine is self-indicating (you'll know it's there!)

The typical waste solution (ie no stainless steel electrode) is safe enough to chuck on the garden or tip down a drain.

Originally Posted by Grahame Collins

Washing soda
It looks like rough crystals, the same colour as sugar, and was available at the supermarkets ,a few years back.
Cleaned up a saw frame that had been underwater in the floods and used an 8 amp battery charger.. Apparently the stainless steel anode I used was a no no as it gave off some nasty gas that was carcinogenic.

The rust ,though was completely removed but I have forgotten the time span it took.

Hope this helps,
Grahame

No carcinogenic gas is given off, but there is the possibility of hexavalent chromium compounds being formed in solution, which eventually has to be disposed of. A retired Industrial Chemist mate of mine says that if you aren't finding brightly coloured traces in your electrolyte, you aren't making these compounds. As I recall, if the voltages and currents are kept low, about 2 to 10 A say, he feels that there is very little likelihood of hexavalent chromium compounds being formed.
I also have used a large stainless steel trough to derust a lathe bed, and I used the trough as the anode. I found no brightly coloured compounds present afterwards. The current was low, as I used an old Arlec Charger4 as the power source, and it will cut out for a while to cool down if the output rises above 4A indicated on my unit. I controlled the current draw by controlling the strength of the electrolyte, so that I had a 100% duty cycle. The job took about 36 hours altogether, as I could only do one half at a time of a 4 foot long lathe bed. All old paint came off as well as the rust, and no pitting or unwanted metal removal was evident to me. I was very happy with the result.
Later when I heard of the possibility of generating nasty compounds, I changed to using scrap iron for anodes, but the process became much messier and the need for frequent anode cleaning made for a more labourious setup.
I am keeping my eyes open for some cheap graphite sheet for anodes, but in the meantime I think that I would use the stainless trough again and keep my current densities low if I need to do serious de-rusting before I find some graphite.
I have not tried molasses or citric acid, but I have used vinegar very successfully to reclaim some old files, and I have to say that I was amazed at the result. I just sat the file in a 500ml measuring flask, and filled it with the cheapest vinegar I could find at the supermarket. The first file was one I had found during a maintenance shutdown at a papermachine, and this 12'' file was found in the pulp chest. It was coated with flakey rust about 20mm thick all over. I gave it some mechanical cleaning and got the rust coating down to about 5mm in thickness, before putting it into the vinegar bath. I left it for about 18 hours, before pulling it out to see what progress I was making. I was surprised at the result, and after a brief run under the Karcher pressure cleaner to clear any sludge from the file teeth, and a hot water rinse to heat the file for a fast drying it was job done. The file looked and cut like brand new, the colour almost identical to a new one but with a very slight brownish tint to the grey, not rusty looking, just slightly different like different blueing/ blacking processes give slightly different results.
I have also used Phosphoric Acid in the form of Ranex rust converter. I wore strong rubber kitchen gloves, and rubbed the shaper table I was cleaning with a Scotchbrite pad, and that large lump of cast iron came up like new. It had been stored outside before I bought it, and was heavily rusted. It took a fair bit of elbow grease, but the table came up really well. I found that if small areas of skin come into contact with Ranex solution, it is no reason to panic, just a timely rinse off with water is all that is needed, but I would always wear glasses or goggles, because if you got some in your eyes, you'd make enough water to break the drought I would say. You should always have water for eye washing or body flushing when handling any strong chemical compounds I think, and if you use common sense, you are unlikely to have any issues.

Edit: Too slow with the typing, Master Splinter said it first RT

Quite a few of us on this forum have use the electrolysis process, the general consensus its......it is the way to go.....no other process even comes close.

I have tried various acids.....I know people who have tried molasses and tomato sauce......but nothing comes close to electrolysis.

It is the Hand Tool Preservation Association approved method...there are details on their web site.

There are supposed issues with stanless........but As has been mentioned in less than industrial scale the problem is insignificant.

There was a time where I had an electrolysis bath running here for around 6 months continuous......I have done a bit of this...... get this process working well and as I say there is nothing that comes close.

a few tips
remove as much of the rust as is practical mechanically.....wire brush ect.....this will speed the process and make it more effective.

keep the bath off the ground...I have had a couple of cane toads jump in mine.....hey get paralysed and die......this then turns the bath into a nasty poisonoius yellow froth.

Lectric washing soada can still be baught in most supermarkets.....I baught 2 bags a couple of months ago in wooolies.......but finding it......ahh yeh......if you are having difficulty...look on the bottom shelf with the other washing obscuritities like dye removers.

Bi carbonate does work...I havetried it...but washing soda is better.

If you have a heavy rusting, particularly deep pitting......runn the item in the bath for a period....pull it out and give it a scrub....then stick it back in


as well as rust the bath will also take paint and other crap off the surface that is not thoroughly adhered.

Remember it is a cleaning product and will cut oil and grease........running a dirty item in a bath will very effectively remove all storts of surface contaminants and quite deeply from the grian of the metal particularly cast.


seriously give it a go.

cheers