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Rust and how to remove it.

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websnail15/07/2011 23:24:57
60 forum posts
Hi all, a newbie here with my first question. If it's in the wrong place sorry.

I have been given a surface plate but it has some light rust on it. I wish to remove it.
My current 'Plan A', is steel wool grade 0000, applied in a figure of 8 pattern but would a chemical route be better?
Thanks for any help
David

Robbo15/07/2011 23:36:26
1504 forum posts
142 photos
These days, for a light infestation of the rust bug, I prefer the de-rusting stuff sold by ArcEuroTrade, it's thick and sticky rather than liquid, and its applied with a nylon scouring pad, so no danger of scratching the metal underneath.
 
Have found my Arc catalogue, its called "Restore Rust Remover Gel" A bit pricy at £14.50 for 250 ml, but it goes a long way because it can't drip off.
 
Hope this helps
 
Phil
 
Sorry, forgot this :   www.arceurotrade.co.uk 

Edited By Robbo on 15/07/2011 23:37:49

ady15/07/2011 23:54:32
612 forum posts
50 photos
Dunk it in malt vinegar for a week or so.
Take it out, scrub it clean, rinse and dry.
_Paul_16/07/2011 01:44:41
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543 forum posts
31 photos
This is what I do,
 
Method one for larger items:
 
Plastic container (Bucket Box etc.) with
A gallon or so of water
A cupful of Sodium Carbonate (Washing Soda)
Battery Charger
 
My Plastic box has a piece of lead sheet halfway around it connected to the battery charger positive electrode and then you connect the item you want to de-rust to the negative electrode/terminal.
 
You can see after a very few minutes the rust fizzing off the surface, it's a non destructive process but if the rust on your item is "heavily pitted" then once it's gone there will be craters.
 
Method two for smaller bits:
 
Citric acid powder from my local Indian Foodstore
Pan of boiling water
 
Simply immerse your item and boil until the corrosion is gone.
 
With both processess un-rusted metal is not affected in any way and unlike using abrasives it leaves no scratch marks.
 
(Something for the health & safety lot: Both processess produce hazardous gasses)
 
Lots of info on the net about it the battery charger method seems popular with home shop restorers me included.
 
Regards
 
Paul

 
 
Niloch16/07/2011 07:38:32
371 forum posts
Milkstone Cleaner from Agricultural suppliers, it's largely phosphoric acid. Follow the given instructions.
Clive Hartland16/07/2011 07:41:16
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2759 forum posts
40 photos
The name of the rust remover is Phospheric Acid and comes in small containers mixed into a jelly, sometimes a liquid which does not stick to the job.
A trade name is 'Naval Jelly'.
Apply and leave for a while and it will eat away any rust, remove with hot water.
 
Clive
Stub Mandrel16/07/2011 19:47:27
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4311 forum posts
291 photos
1 articles
A friend who collects old tools got a tip from someone who buys rusty old tools at boot sales - he fills a bucket with them , then tops it up with cheap and cheerful 'value' coke.
 
Neil
blister16/07/2011 20:54:00
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28 forum posts
3 photos
Try a mix of Molasses and water ( half and half) in a plastic bucket with a lid.
Environmentally friendly and the rust still hasn't come back after 15 years
 
Phil
Phil P16/07/2011 21:15:13
792 forum posts
194 photos
I have used this for removing rust from antique musical box combs.
 
 
You can buy it in the UK here.
 
 
Phil

Edited By Phil P on 16/07/2011 21:16:46

John Stevenson16/07/2011 22:27:24
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5068 forum posts
3 photos
Phosphoric acid whilst doing a good job has to be treated with care because the fumes causes everything else to go rusty.
Stick a tub of this in the workshop overnight and you'll know all about it.
 
I did some experiments a while ago on a related subject that had good side effects on rust removal.
 
I get some plates cut at the laser cutters in 200 at a time in 4mm, 5mm and 6mm thick steel. The plate laser cutters use is made for lasers and has a shiny black coating that stops splatter and damage to the lens.
 
Unfortunately this oxide coating damages the webs on the small drill used on these jobs and drill breakage is an issue. The answer has been to surface grind the top face before drilling but the oxide coat clogs the wheel and wear wear now becomes an issue with wheels costing £80 each. So the answer has been to send them out for Lumsden grinding at 50p per side which soon adds up plus a 3 hour round trip.
 
After asking advise and trying things out I found that Patio and brick cleaner is 90% hydrochloric acid, not 90 % proof. If you place these plates in for 24 hours they come out with a grey sheradised finish on them and no oxide, also works on any black steel like angle etc.
 
Leaving in longer doesn't do anything unto wards. The solution / fumes does not affect machines, I have had a big 5 gallon tub of this on the floor for months parked at the side of two dividing heads and 3 vises, none have discoloured.
 
Now the spin off, seeing as how it cleaned steel up I tried it on a rusty piece of metal, to whit a tap I found jammed in the base of an old cupboard this was absolutely red rust and to be honest it was scrap.
Left in for 2 days and when it came out it had the sheradised finish, was perfectly clean and when you rubbed you finger on the cutting edge it was sharp !!
 
Amazingly the sized etched on the shank stood out like chrome.
 
Since tried other makes and found the most cost effective is one from a big box builders merchants called Selco at about £5 for a gallon which you mix with water about 4:1
 
It's not a nasty chemical you can put your hands in it just for putting bits in and out but best to wear gloves. to dispose of it you just throw it on the patio and wash down the drain, after all that's what it was made for.
 
Trick is to look at the label in the big box stores, it needs to say "Contains Hydrochloric Acid" steer clear of anything that says green.
 
John S.
websnail16/07/2011 23:24:07
60 forum posts
Thanks guys, some interesting ideas.
 
My surface plate is 18"x18"x3", so is a touch too large and heavy for some of the ideas.
 
I will be following up on some of the ideas. I also have a vernier height gauge that I wish to 'clean up' .
Mark Rand16/07/2011 23:46:40
1136 forum posts
15 photos
John,
Are you sure you haven't got that arris-about-face?
 
In the experience of most folk (me included) Hydrochloric acid fumes will rust anything in the same building in short order. So will fumes from a common salt hardening crucible. Phosphoric acid, in contrast, is relatively benign. Indeed, I've had a plastic dustbin full of (originally) 10% phosphoric acid in the workshop with a fish tank aerator in it for the last three weeks, evaporating the excess water so I can put it into a smaller container. it hasn't caused any corrosion problems at all.
 
On the other substances, Evapo-rust, molasses and to a lesser extent, citric acid, act as chelating agents. They will capture the iron oxide molecules and float them off. Gentle scrubbing with a wire brush every day will help the process.
 
Hydrochloric and phosphoric acid will both reduce the iron oxide, but both will also dissolve iron as well.
 
Electrolytic cleaning with sodium carbonate (washing soda) as an electrolyte will reduce the ferric oxide (rust) to black ferrous oxide, making it easy to brush off. Eventually, it'll reduce the ferrous oxide too.
 
 
Having tried all these methods, I'm currently a convert to diluted molasses, I hauled a milling machine table out of a 12"x56" pool of it in the workshop yesterday after two weeks of soaking. It's a lot slower than the other methods, but it seems to do the job very well. Makes the shed smell interesting too
 
John Stevenson17/07/2011 00:11:07
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Moderator
5068 forum posts
3 photos
Mark,
Only made the comment of Phosphoric acid from what I have read as I have never used it personally but I'm on my 3rd gallon, diluted to about 12 gallons of patio cleaner and the label clearly says Hydrochloric acid.
 
I saw the old tap I did the other day , tomorrow I'll put a picture up, it really surprised me, pity I didn't have a before picture but it was just a red lump. If I hadn't dropped it in the solution as an experiment I would have just binned it.
 
I only posted this as an aside on rust removal, for me it's main claim to fame id removing the black oxide off steel which it does in 24 hours and no special gear like the electrolysis method.
 
John S
John Stevenson18/07/2011 22:23:05
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Moderator
5068 forum posts
3 photos
Sign of a warped mind replying to ones own post <g>
 
But I did promise a picture of that tap, as i say i had no before picture but these two are the after pictures of what was a red rusty lump.
 
 
Just as it came out the solution, not touch at all.
 
 
 
 
And amazingly the size stands out. This came from Erricsons telephones and accounts for the weird size, they used to make al their own taps and dies.
 
Just by chance the body shop guy across the road came over this afternoon and brought a bucket full of Morse taper drills he'd found in a barn he's just bought.
Not sure if they will be reclaimable but nothing to loose.
 
 
This is one of the worst although there isn't much to choose, can't read anything on it and I don't want to start wire bushing. Quick check with a caliper and it looks to be 26mm or may be 1 1/32"
So bunged it into the plaggy tub and will fetch it out tomorrow or the day after and see how it's come out.
 
John S.
Ian S C19/07/2011 11:46:42
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7468 forum posts
230 photos
A friend bought in a large handful of MT drills, I converted them to parallel shank (1/2"), derusted those that needed it, and sharpened them. They were inch size, ranging from 3/16" to 3/4", and now he has a set of drills he can use. Used citric acid for the rust removal, the electrolitic method is not recomendedfor the higher carbon steels, it tends to cause hydrogen embrittlement. Ian S C
John Stevenson19/07/2011 12:49:29
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Moderator
5068 forum posts
3 photos
Had a quick look just now at that drill and this is how it's come out after just a rinse under the tap.
 

 
Not the prettiest drill in the box but given the state it was in and about 18 hours later it's rust free.
The plates with it are the ones that get descaled. Actually that one in the picture has been in for about a month !!
 
I missed it .
 
Quick wazz with the loose flap wheel and this shows up.
 
 
So 1 and 1/32".
 
This stuff costs about £6 -£7 per gallon and you dilute it about 3:1 so very cost effective.
 
John S.

Edited By John Stevenson on 19/07/2011 12:50:31

Ian S C19/07/2011 13:52:44
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7468 forum posts
230 photos
John, what price a drill that size new? Ian S C
chris stephens19/07/2011 17:21:17
1049 forum posts
1 photos
Hi Ian,
In the J&L catalogue a Dormer 1" is £54 and a 1 1/16" is £64, a Guhring 1 1/32" is £71, all prices are naturally plus VAT. OUCH!!!
Car boots and Patio cleaner here I come.
chriStephens
Windy19/07/2011 18:01:11
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880 forum posts
185 photos
Aldi was selling 400ml phosphoric acid washing machine descaler (Kilrock. Big W).
I checked with the manufacturer and it is 25% phosphoric acid plus fragrance.
As regards it affect on iron I put a file in the acid solution and forgot about it for a few days.
I now have a very small useless file
 
Windy
Gray6219/07/2011 18:04:59
1056 forum posts
16 photos
Well, after several attempts with the caustic soda/electrolytic method (and very little success), I decided to give the Hydrochloric acid method a go. Quick trip to the local builders yard, parted wit £6 for 5 Litres of high strength brick cleaner and I have, in an afternoon, de-rusted an old 12" 4 jaw chuck which I acquired some time ago. One of the jaws has freed up so a little more soaking in the HCl and I think I may have rescued a doorstop.
 
BTW, this stuff absolutely stinks, make sure you use it outside or in a well ventilated area.
I'm going out tomorrow to buy another 5L and a bigger container so I can get the whole chuck immersed. I'll let you all know what the results are, (wish I'd taken a before pic now).
 
The solution I bought is 18% HCl and seems to be very effective with no dilution.

CB

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