Thread: de rusting really rusty iron

Try electrolysis - it can make good metal out of the rust.

All you need to know is in this article from the HTPAA website

Using acid (citric or acetic) dissolves the rust, losing the chance to restore the metal. Similarly, using friction (wire brush, emery cloth, etc) just scrubs the rust away. This tends to make the pits bigger!

For the chunkier stuff where a precise surface isn't required and there's a lot of rust to shift and you are in a hurry....hydrochloric acid (brick cleaning acid from the hardware store) works a treat. Dilute it 10:1 (add acid to water, not the other way around!) and chuck it in. Mind the fumes, they are nasty. Check on it every ten minutes or so. It will attack the iron, but its a very very slow reaction compared to the rust.

Have you seen these links in the Best of?

http://www.woodworkforums.ubeaut.com...ead.php?t=8243

http://www.woodworkforums.ubeaut.com...ead.php?t=8242

http://www.woodworkforums.ubeaut.com...ad.php?t=29549

There are also some more threads about rust removal & rust prevention on tools but I can't find them in a hurry.

I wouldn't recommend HCl, unless you sit there and watch it. I have been gone 2 minutes and it has gone too far. Also some of the thinly rusted iron will be being eaten while teh thick rust is still there. Using HCl also requires a thorough wash in water afterwards and apply a protective coating, otherwise it will start rusting again

What I use all the time is phosphoric acid. I have used raw phosphoric but I now use a proprietary product called Rannex because it is already mixed in the right proportion and it is dead safe - it won't dissolve any iron, just the rust, it actually converts rust (iron oxides) into Iron Phosphate.

Rannex is Phosporic acid, water and detergent to act as a wetting agent. The directions on the bottle are pretty well spot on. You can soak items in it but you can't reuse the solution again after that. Painting the items is a better way to go, you just let it dry and that's it. If some rust remains repeat the process until there is no rust. The iron is left sans rust and with a blue black protective coating of iron phosphate that does not allow the iron to rust for some time. This can be sanded off if you want shiny iron.

Thanks everyone,
I'll take the easiest option because there only old farm things and because I'm too idle to do it properly.
cheers
Astrid

I know of people that restore old cars, the wheels and other bits and pieces useing Molassis (watered down). They keep it in a big plactis drums 200L and just let the items have a sit in there for a few days... I have a feeling that the Molassis may have some Urea in it also, may have to search some more or perhaps someone else here knows the process also??? But i do know that it doesnt attack any of the good metal and does a very nice job.

i use elcheapo brown vinegar depending on the amount of rust a day or so and a bit of a scrub with soapy water and its back to bare metal. use it on old chisels and plane blades etc but cant see why it wouldnt work on bigger things just more vinegar

Thanks Tanii51

thats what I was looking for, Im selling this stuff for about $15 a piece so dont want to spend hours doing it up.

Astrid

Well, if you are using vinegar you might as well add kitchen salt (sodium chloride). It combines with the vinegar (acetic acid) to produce a weak solution of hydrocloric acid, which works better as already explained.

Thanks Tanii. I've just tried vinegar for the first tiime and it worked
Jim

Get a couple of tubs of citric acid powder from the supermarket, dilute in a bucket of water, and leave the items there for a week. Then scrub with steel wool/wire brush.

This works GREAT for old files - renews them.

Regards from Perth

Derek

thanks frank n ernest ill give it a try ( theres always something to learn eh)

Originally Posted by derekcohen

Get a couple of tubs of citric acid powder from the supermarket, dilute in a bucket of water, and leave the items there for a week. Then scrub with steel wool/wire brush.

This works GREAT for old files - renews them.

Regards from Perth

Derek

G'day Derek, I have used vinegar to de-reust lightly rusted stuff before but had not thought of files.

Just some info, does vinegar work as well as the citric acid?

How do you overcome the "flash" rusting, which of course leads back to the original problem, after cleaning up the metals?

Do you coat the files with anything?

Regards,
Bob

wash the vinegfar off immediately in soapy water and coat with oil or crc etc.