How To acid bath rusty parts?

[Ridels_mtb]

I would like to know how all you bike resto guys acid path old parts?
i looked on here and on google but couldn't find anything so i was wondering what chemicals you use and all that

Cheers, Tom

[aussieidiot]

There are a few threads dealing with Oxalic acid baths on ozbmx and vintage bmx.

Basic run down.

Go to Bunnings, ask for Oxalic acid. Chance are you get some dipshit who has no idea. So ask where the industrial cleaning section is (where the hydrochloric acid is).

Grab a 2kg bottle (its a white bottle like a big round milk bottle) of powder. The brand is Diggers.


Next you need a plastic container to make the solution. They recommend 100g acid to 1L water, but i used 100g to 1.5-2L water and it worked well. I reckon go even thinner as its hard to get the stuff off when it sets in nooks and crannies.

I used a 60l tub filled about half full. Always add the powder to the water (not sure why, its just what others have said)

Mix it up and drop in ONLY chrome parts. no alloy or other metal as it will either eat it or make it look like crap.

Here's one at the start.
http://i727.photobucket.com/albums/ww280/aussieIDI-07/bmx/bratz/bratz14.jpg

and after a few days

http://i727.photobucket.com/albums/ww280/aussieIDI-07/bmx/bratz/bratz25.jpg

I found a difference after about 6 hours when you should pull the parts out and give them a wipe over.
Use soft dishwashing scourers to remover excess. You don't want to scratch the chrome further.

The bath will only remove rust and not fully refurbish the chrome. pitting and flakes will still be present.


SAFETY!!!!!!

Use gloves and best if you wear eye protection. one splash of this stuff and you could lose an eye! Seriously, it ain't worth the risk! I had a few splashes before I thought I'd better do the right thing.



Before
http://i727.photobucket.com/albums/ww280/aussieIDI-07/bmx/bratz/bratz2.jpg

After
http://i727.photobucket.com/albums/ww280/aussieIDI-07/bmx/bratz/bratz22.jpg


Once you've finished, pull the parts out and clean them up with water. Use a water dispersant like WD-40 (I prefer Inox as its not a degreaser like WD and will protect against rust) inside tubing.
Then pull out the polish and rags and get to it. I used a Meguiars metal polish with a coating that helps keep the finish longer and resist rust.

[*bj*]

Shite that came up clean!

Does this stuff strip paint off chrome surfaces?

[aussieidiot]

I'm not sure. I don't think so because stickers didn't get affected. Although the longer you leave it in, the better it works.

One big word of warning, it eats some alloys! The rivet through the brake lever got eaten away quickly. so be careful.


Oh and its biodegradable so when you finish you can just pour it out. Although I'd probably water it down as you pour. You can also leave it in the bucket for next time. Some guys just have a permanent set up ready to go.

[Greg]

Hey! that is great info!

I've never seen that done before & the results are fantastic!

That bike is really going to look sensational!!!!!

[Ridels_mtb]

thanks aussie heaps of good info there ill give it a go soon.
Cheers, Tom

[aussieidiot]

No worries.

I only just learned about it recently too!

[Lorday]

I used a 60l tub filled about half full. Always add the powder to the water (not sure why, its just what others have said)


Exothermic reaction. Same reason you ad conc. acid to water rather than water to conc acid.

[PowderCoat]

because? water has a higher thermal efficiency and a large body of water will absorb that heat. other way round you get super heated water mixed with acid splashing all over the place. fun :)

[Lorday]

Water = High specific heat capicity.

[stevebaby]

Vinegar from the supermarket...$2.50 for 2 litres.

[Lorday]

Go to Bunnings, ask for Oxalic acid. Chance are you get some dipshit who has no idea. So ask where the industrial cleaning section is (where the hydrochloric acid is).

Grab a 2kg bottle (its a white bottle like a big round milk bottle) of powder. The brand is Diggers.


*Chances are its with the kerosene/methylated spirits etc..... Try near the paints sections.

If you come to Norwest Bunnings it's in isle 16, and the polishes/cleaners are in 35 ;) :p

[aussieidiot]

Lorday, I went to Norwest.

Its right down the back (aisle 35 probably)

There was nothing in the paint section that was as strong and priced well.

[AndronicusPrime]

Haven't had luck in finding this at Ashfield bunnings, 1st time I managed to find the shelf label for the oxalic acid which was next to the hyrochloric acid but there was non in stock, 2nd time even the shelf label was gone.

[aussieidiot]

I still have a bath set up if you want to use it?

I'm out at Schofields and would be happy to let you use it. Save you some cash......

[munga]

oxalic acis is aka wood bleach if it helps

[aussieidiot]

Wood bleach is usually a watered down version and costs a shedload more for the same amount.

You need the crystals because you really need to fill a 60L container half full to fit any bars or 20" wheels in it.