Sciencemadness Discussion Board

Rust solvent

texaspete - 22-10-2008 at 05:35

Anyone know of a good OTC rust solvent that is less harsh than phosporic acid? (I want to remove rust from my shoes)

Phosphor-ing - 22-10-2008 at 05:37

Rust stains on your shoes, or you actually have exposed metal on your shoes that is rusting?

Pomzazed - 22-10-2008 at 06:21

try oxalic acid solution? they should brush the rust off

smuv - 22-10-2008 at 08:13

White vinegar, then water to wash away the smell; I would allow the area to soak under a paper towel saturated with vinegar for a while before you actually attempt to scrub. If that doesn't work then consider something harsher.

Of course oxalic acid will work too, but you can't beat the cheep ready accessibility of vinegar.

Hydrazine - 22-10-2008 at 12:21

I wouldn't use oxalic. Too poisonous for use on shoes.

Vinegar is a good start.

Dilute hydrochloric acid should work well if the vinegar doesn't cut it.

12AX7 - 22-10-2008 at 12:37

Quote:
Originally posted by Hydrazine
I wouldn't use oxalic. Too poisonous for use on shoes.


Got a case of foot-in-mouth, have you? :P

Ozone - 22-10-2008 at 15:45

CLR cleaner works well. The main ingredient is glycolic acid (chelator), IIRC. If this is too expensive, a reductive agent such as sodium bisulfite can do the trick (see also sodium hydrosulfite). See also, a combination of hydrosulfite and EDTA, which works both ways.

Cheers,

O3

kclo4 - 22-10-2008 at 15:54

If it is on leather or a colored material, wouldn't the sulfites bleach it?

[Edited on 22-10-2008 by kclo4]

Ozone - 22-10-2008 at 19:40

Good point, I don't believe that the shoe material has been described. Are they leather, or other (polymer, etc.)?

Cheers,

O3

texaspete - 22-10-2008 at 19:43



Now imagine red iron oxide powder all over them.

Thanks for all the suggestions! I think I'm gonna try the vinegar out tomorrow.

kclo4 - 22-10-2008 at 19:46

I question if Vinegar reacts with Fe2O3, I was producing some Iron acetate recently from Vinegar, and the acidic solution over time had what appeared to be Fe2O3 fall out of it over time. I figured it was from the air oxidizing it somehow. Also I don't think HCl does either... I've always thought this was the reason they use H3PO4 as a Rust removers - its one of the few acids that react with it.

I could be wrong, but something sounds wrong to me.

Hydrazine - 22-10-2008 at 20:46

Quote:
Originally posted by 12AX7
Got a case of foot-in-mouth, have you? :P


MSDS gives it a high health hazard rating. Why chance it?

Unlike vinigar or HCl, oxalic acid residue won't evaporate away as the shoes dry out.

The potential for oxalic acid residue in shoes doesn't seem like a good idea.

Pomzazed - 22-10-2008 at 22:00

Just wonder why iron oxide "powder". are you making thermite things?

Well, if its powder covered around in mini-fiber hole and not really a stain, why dont try a vacuum dust cleaner first? that should work well at least for removing all those rust particles, before finishing up with dilute acid.

IMHO, vinegar stinks the shoes and take days to evaporate all

Formatik - 22-10-2008 at 22:07

As far as Fe2O3 reacting with acetic acid. It doesn't I've tried forming iron acetate too. I used both glacial acetic acid and vinegar, neither reacted not even sitting for weeks. Even heating with vinegar didn't dissolve it either. But then again I was using chemically pure Fe2O3 which is different than just rust.

My choice would be similar to Ozone's, for dissolving rust I would let an aqueous mixture of sodium hyposulfite and metabisulfite solution soak in the area. But this sulfite rust remover one can get from hardware stores. I would try this on my shoes rather than an acid, but best to test an area to see if the fabric might be affected. Though I don't think it should react.

texaspete - 22-10-2008 at 23:00

Quote:
Originally posted by Pomzazed
Just wonder why iron oxide "powder". are you making thermite things?

Thats the plan.
Quote:
Originally posted by Pomzazed
Well, if its powder covered around in mini-fiber hole and not really a stain, why dont try a vacuum dust cleaner first? that should work well at least for removing all those rust particles, before finishing up with dilute acid.

Well naturally the first bright idea I had was to use a wet paper towel, which did manage to get a bunch off, but also made what little remained a lot worse. And no, its not just powder in the mini-fiber holes, its just really fine powder on about half the shoe. It almost looks like a blood stain.
Quote:
Originally posted by Pomzazed
IMHO, vinegar stinks the shoes and take days to evaporate all


I'll keep that in mind, thanks.
Quote:
Originally posted by Formatik

My choice would be similar to Ozone's, for dissolving rust I would let an aqueous mixture of sodium hyposulfite and metabisulfite solution soak in the area. But this sulfite rust remover one can get from hardware stores. I would try this on my shoes rather than an acid, but best to test an area to see if the fabric might be affected. Though I don't think it should react.


Is it sold as rust remover, or as something else?

Thanks again all!

[Edited on 23-10-2008 by texaspete]

Formatik - 22-10-2008 at 23:23

Quote:
Originally posted by texaspete Is it sold as rust remover, or as something else?


That's right. You might have to look around to find it. Though I've only used this on clothes (for iodine stains), and not shoes. It didn't leave any odor by the clothes. I remember for dissolving rust this aq mixture had to sit with the rust a while.

[Edited on 23-10-2008 by Formatik]

DrP - 23-10-2008 at 03:27

Can't you brush and polish it off? Most rust converters use tannic acid iirc and of course the phosphoric you wanted to avoind.