VERY aggressive rust removal easypeasy!

[TurboShed]

I've started an old shear restore using washing soda.......lotsa pics here:

http://microzone.us/weldingforum/index.php/topic,649.0.html

If anyone knows anything about the old British Steel shear, I'd love to hear it.

Quality thread! Like brewing beer but... different

 

[jon-eastanglia]

i have used this method a few times on motorbike restoration bits, and a few times the whole frame using our blue dry plastics bin, and a 40amp arc welder for power overnight. This is not a good idea, as the welder plug can melt into the socket if on too high a setting!
a ac-dc power supply will suffice around 15-20vs for smaller items in a plastic tub. The annode should be clean, this will dissolve into nothing eventually. Table salt can be used, i dont know whether it works as well as sugar soap. The annod should be suspended and not touching the sides or bottom of the tub, the closer the annode to the cathode the higher current / faster the process gets, it should be positioned so that it covers the cathode equally or moved about every few hours. volume of water doesnt seem to matter. I think it works well, and used this on some old mk1 fiesta brake calipers, but its a time consuming process. Do it outside, and dont sit there breathing in the bubbles too long! The rust will appear black and bits will wash away easily, paint is not removed so easily, but will bubble in places so you can just use some paint stripper too. There you go.. heres a website: http://www.pembleton.co.uk/techpages/derusting.html

 

[MG David]

I have used this method as well using washing soda. You can use caustic soda but I don't used it for derusting. However, I do put some parts in caustic soda in advance to remove dirt, oil and paint so that the derusting works better.

 

[Chickenjohn]

I have an even easier and safer/less messy method for rust removal. Get some citric acid and make a 5-10% solution in water- 1 ounces in 1 pint (50g in 1 litre).

Then immerse the item in the citric acid overnight, for deep pitting, brush the pits with an old toothbrush at intervals.

For small items, place in the citric acid solution in a plastic tub (margarine tub etc) and microwave on low power until the solution bubbles. Leave to cool and the rust is gone.

This method just leaves you with a clean dull grey steel and a green/brown non toxic iron citrate solution you can dispose of.

 

[Coo]

Is citric acid easily obtainable ?

 

[fingers99]

Is citric acid easily obtainable ?

It's the kind of thing you used to be able to get from any decent chemist -- you might try Boots.

But some stuff you'll have to get on fleabay: it was the only place I could get Hydrochloric, guy was selling phosphoric acid, too, which is a common rust remover/passivator.

 

[zardoz]

A small ounce pack of Citric acid is often quite dear these days. Better if you can get it retail. Try the larger home brew shops maybe. Lots of places don't sell it these days, as junkies use it to break down street heroin into an injectable form!

edit: just looked on ebay, it can still be bought quite cheaply there in large amounts pretty cheap (500grams 1Kg etc)

 

[Chickenjohn]

I got 5kg of citric acid for 50p a kilo a few years ago! Buy in bulk because the postage can equal the cost with small amounts. Citric is easily available from various sources on the net.

I wouldnt use hydrochloric acid as its corrosive to the skin and will dissolve good steel as well as rust.

 

[Jack62440]

I tried this method about a year ago to clean up some E-Brake lines. I made a long box out of scrap boards and used a old water bed liner. I think it should be done outside because of the fumes and mess. Only problem is it is hard on your battery charger. I burned mine out after a number of jobs. I had a small odd shaped job to do later on and didn't want to be bothered with the Mess, so I poured a large bottle of "Coke a Cola" into a plastic tube and left it there for a day. Nice and shinny Just thinking about what that crap does to your body Jack

 

[joe666]

i find taking the rusty thing to work and dipping it in 2000 litres of hydrochloric acid does the job

 

[aero]

I tried the electrolysis method on some motorcycle parts. My opinion was that it takes too long and doesn't actually remove the rust. It does take some of it away, but the rest is just converted, to whatever the black stuff is. There's much better ways to remove rust.

If you want something that acutaully REMOVES all the rust try this stuff.

http://www.bilthamber.com/deoxc.html

I think its nothing more then muric acid which is commonly used to regulate the pH of swimming pools.

A friend uses it to remove rust from the inside of motorcycle fuel tanks. It can be done without harming the paint on the outside.


One very important point: when using the ectrolysis you need something to control the current. If using a battery charger put a 21watt bulb in the circuit, or you might melt the charger. I'm guessing thats what happening with the welder, its drawing too much power as you have basically a dead short on the output.

Oh and buying large quantities of citric acid may bring plod knocking. Its used in the manufacture of certain illegal narcotics

 

[Chickenjohn]

i find taking the rusty thing to work and dipping it in 2000 litres of hydrochloric acid does the job

Yes, hydrochloric acid will dissolve rust and if you leave the item in too long will also dissolve the steel item.

 

[joe666]

Yes, hydrochloric acid will dissolve rust and if you leave the item in too long will also dissolve the steel item.

yeah i know i over see a phosphate plating line at work we also do zinc, nickel, trichem, anodising ect ect
you can also use electrosoak which is alkaline run a charge through it and the rust will fall off
i only use chemicals to strip any of my own personal parts if a have to. glass bead or ally oxide blasting is all thats needed most the time
if you use hydrochloric you must treat the steel as itll flash rust when you take it out the acid anyway...phosphate is best
we also have a new non toxic deruster from saftey clean just drop part in over night and rusts gone by morning you can put your hands in this stuff
got to be safer than playing with electric and liquids....

 

[Chickenjohn]

yeah i know i over see a phosphate plating line at work we also do zinc, nickel, trichem, anodising ect ect
you can also use electrosoak which is alkaline run a charge through it and the rust will fall off
i only use chemicals to strip any of my own personal parts if a have to. glass bead or ally oxide blasting is all thats needed most the time
if you use hydrochloric you must treat the steel as itll flash rust when you take it out the acid anyway...phosphate is best
we also have a new non toxic deruster from saftey clean just drop part in over night and rusts gone by morning you can put your hands in this stuff
got to be safer than playing with electric and liquids....

I agree and I expect the Safety Clean machine actually uses Citric acid as its main rust removing ingredient- it's safe (you can and often do eat it- its in fruit!) non toxic and as you say you can put your hands in it.

 

[Benji]

What sort of concentration citric acid should be used and do you just hose it off after removal from the bath or do you have to neutralise the acid before painting? Have got some spoked wheels from an old costermongers cart to do and have been dreading cleaning them up.

 

[Chickenjohn]

about 10% citric acid works well. When all the rust is removed, wash off the citric and then I would paint the steel with ~10% phosphoric acid to etch and stabilise the steel before painting.

 

[Benji]

Thanks for that Chickenjohn, have just ordered citric acid off fleabay so will see what the results are when it arrives and post piccies if I can work out how.

 

[chriskelland]

Hi,

Don't worry about plod if you are buying citric acid, it's Lactose they are interested about, in fact there is a notice on the home brew website to the effect that they have to keep records of who buys it. I use quite a lot of citric acid mainly for cleaning copper before and after silver soldering.

Chris.

 

[aero]

It wasn't a serious comment about Plodd turning up....just an observation

But using citric acid or similiar (I'd heard that there are other chemicals such as the acidd used for swimming pools) seems much safer then messing about with water, power supplies connected to the mains and a proccess that builds up qualities of poisionous/flammable gasses.

 

[chriskelland]

Quite.