Rust removal

[MattF]

Just wanting some info and opinions on some of the various methods of rust removal. Preferential method is electrolysis, but for obvious reasons, with large and/or heavy items, it's not always a plausible option for me personally. Blasting is something I've no intention of trying, same with any power tool based methods, so that literally leaves citric acid and wire wool and oil? Have I overlooked any methods?

With the citric acid, what's that method like for the flash rusting once the piece being derusted has been washed down with water, and is it suitable for use on the likes of machined surfaces? How labour intensive is wire wool and oil, (I'm guessing quite a bit)? What type of finish do both methods give?

 

[outofthefire]

Molasses is good if you can submerge the part, but its slow takes two to three weeks. Have a look on you tube there's quite a few videos

 

[MattF]

Molasses is good if you can submerge the part, but its slow takes two to three weeks.

Time wouldn't be a concern, but the submersion bit might be awkward. It's for the bits which are practically hernia inducers which I'm trying to figure which method to use, so they'll likely just be worked on directly on the floor or bench at best. Almost killed myself getting some of these bits in the shed, so the thought of trying to hump them into a vat or the like would likely give me nightmares.

 

[chunkolini]

I have used citric acid on larger components by soaking kitchen towels in the solution, wrapping them round the rusty bit and then wrapping it in cling film and leaving it overnight.
Very effective.
Should be ok on machined surfaces. To avoid flash rusting dry it and give a light spray of WD40 or similar.

 

[MattF]

I have used citric acid on larger components by soaking kitchen towels in the solution, wrapping them round the rusty bit and then wrapping it in cling film and leaving it overnight.
Very effective.

Cheers. Hadn't considered doing it that way. More effective and far less prone to running off than just brushing the stuff on. Good to hear it works well. What type of ratio do you find best for the acid/water mix?

Should be ok on machined surfaces. To avoid flash rusting dry it and give a light spray of WD40 or similar.

It's similar to electrolysis then, in that time is of the essence in getting it dry and a coat of something onto it?

 

[chunkolini]

I was using the Bilt Hamber stuff, DeOxyC.
Turns out is basically Citric acid.
I just make up a saturated solution, use hot water and keep adding until it stops dissolving. Wear gloves as it smarts a bit on small scratches.
I was pleased with the tissue idea. I did try making a gel but could not find anything that would not dry out over night.
Regards protecting the surface, I suppose it is clean and damp, hmm those rust bugs just love it.

 

[Flathead_Dave]

Have you considered this?

http://www.bilthamber.com/deox-gel


Or maybe not (see above).

 

[chunkolini]

I did look at that for about 6 seconds, the price scared me off.
I felt my wallet pucker.

 

[Flathead_Dave]

He did it again.

 

[MattF]

I felt my wallet pucker.

We usually phrase it slightly different over here. Just been looking on Ebay, and what are these prices like, (I think citric acid is the first on the list)? Seems cheap enough(?), and this seller seems to supply a few tempting, useful chemicals, (bicarb, copper sulphate, borax).

http://www.ebay.co.uk/sch/home_and_hobby_chems/m.html

 

[aametalmaster]

I use Muratic Acid added to some water in a bucket. If its really rusty and a smaller part i just use the acid. Then a rinse off with water and baking soda and dry real well either in the sun or with compressed air. If its not going to be painted right away i will oil it. The acid can be bought at home centers and hardware stores as its used to remove excess mortor from brickwork and to adjust PH in swimming pools...Bob

 

[MattF]

Molasses is good if you can submerge the part, but its slow takes two to three weeks.

Thinking a bit more about that method, that could be handy for doing a lot of little bits I have knocking about like drill bits and suchlike. Was planning on doing those via electrolysis ar some point, but a slow soak which leaves them easy to clean would be better, and I could just chuck them all in the bucket. If I've read the info correctly online, it's a straight 9:1 water/dark treacle, (I prefer to stick with our native stuff ), mix? Is it just a case of washing/scrubbing down in plain water afterwards, and have you noted any ill effects on certain metals, or does it seem safe on all metals, including brass and copper?

I use Muratic Acid added to some water in a bucket.

Muriatic/hydrochloric is probably a tad strong for my liking, to be honest. Granted it's diluted, but trying to stick with the weakest, (in pure form), usable options possible, preferably. Just incase I do try that at some point though, does the bicarb totally neutralise it, or can it still be problematic afterwards?

 

[kelsham]

I bought some citric acid from Ebay and found it works really well. I used jenolite after removal from the tank to phosphate the surface.

One bracket i cleaned last year still free from rust in the garage, must get round to painting it.

The mixture gradully gets blacker as parts are processed until it looses effectivness.

I consider it a better method than electrolysis as it works wherever it wets the surface and not just in line of sight of the electrodes. Must admit I have not tried the electrolysis method though.

I also used Bilt Hambers product more expensive and gave similiar result.

Kels.

 

[Seano]

It's for the bits which are practically hernia inducers

Jeez Matt, what are you de rusting, a chuffin battleship ......

 

[Chipper]

Citric acid - so cheap, so easy and safe. Very fast if you make up a hot solution, done in an hour usually. Leaves a coating so haven't had much flash rust problems rinsing and drying with hot water.
Dissolves galv as well, which has been handy on misc Landy bits for welding.

Deox gel is good if you can't dunk a part and need small bits doing. It's messy though, needs covering with clingfilm overnight and can still dry out at the edges making it a bit of a pain to get rid.
Suppose citric+wallpaper paste would do similar for cheap.

Jenolite/phosphoric's good for wiping on, if things aren't too rusted up.

And there's always strip & clean discs.

 

[chunkolini]

Tried wallaper paste, very messy and dried out too quickly.

 

[MattF]

I consider it a better method than electrolysis as it works wherever it wets the surface and not just in line of sight of the electrodes. Must admit I have not tried the electrolysis method though.

I've always found that a slightly misleading way that they tend to phrase it in the writeups and the like. It's true that certain areas, (ones which are covered by some other part or internal in a cylinder, for example), won't derust until exposed more directly to an anode, but the line of sight bit does tend to suggest it's a tad more restricted than it is. Path of least resistance far better describes it, but current will also flow through parts of the item which aren't directly looking at the anodes, as long as they have a clear path.

Jeez Matt, what are you de rusting, a chuffin battleship ......

Some of the stuff feels like it. Bearing in mind this is mostly pre 50's stuff, back when there was never even a thought of using pressed steel or suchlike, there's a lot of heavy cast stuff. There's the floor standing pillar drill, (the whole column and head is one piece, and the base/foot plate alone for that is just liftable by one person), the Drummond 5", (that one caught me out a tad on size, as I never anticipated that making a lathe have an extra 1-1/2" centre height would also mean it tripled in bed size and weight over the 3-1/2" ), the Rapidor beds, plus probably the Pollard bench drill. That thing truly is a dead weight. You honestly wonder how they managed to make something that size so damned heavy. I'm sure they must have made that thing from some super dense metal.

And there's always strip & clean discs.

What are those?

 

[Country Joe]

And there's always strip & clean discs.

What are those?

These things - they work extremely well, too.

http://www.weldequip.com/cleaning-fleece-115mm.htm

CJ

 

[hotrodder]

Barium sulphate is (at least one of) the thickening agents used in pickling paste, mentioned here for example... http://www.enspectechnology.com/fmcs03.htm Appears to be used as a thickening agent/filler in other things too. Google shopping suggests it's available from some online Chemists so i'm thinking it's probably easy enough to get locally even if it's not a regular stock item like citric acid. It's been on my list of things to look into/experiment with for a while now but keeps getting bumped by something more important/more fun

 

[outofthefire]

If I've read the info correctly online, it's a straight 9:1 water/dark treacle, (I prefer to stick with our native stuff ), mix? Is it just a case of washing/scrubbing down in plain water afterwards, and have you noted any ill effects on certain metals, or does it seem safe on all metals, including brass and copper?

Yep just hose it off, as far as I know no environmental issues which you might get from using acid, never tried it on brass or copper.

Buy molasses its about £8 for 4 litres it's as native as treacle its usually used as an additive in animal feed so any equine or agricultural shop will sell it.