Fast Method for Corroding Steel?

[dwrighto]

I am looking for a method which will corrode steel within a few days.

 

I've searched the web and got a ton of possibilities, but mostly from artists who purposely create rust for their sculptures (i.e. they aren't chemists).

 

The latest method I tried is a bucket of Bleach, Vinegar, and Salt. It produced a surface rust within hours, but it's been about 36 hours and I gave one of my test specimens (bolt + nut) an inspection and found the rust easily wiped off (it's also 20 degrees F out there so that isn't helping the chemical rxn)

 

I have 3 dozen bolt + nut (hand tightened) combos which I need to corrode to a point where the nut seizes and needs penetrating oil to free. This experiment is to test the effectiveness of various penetrating oils for use in a senior design project so I can get out of college and move on with my life ha.

 

I don't have access to fancy tools, but I'm willing to use electricity and whatever corrosive compounds I can get at walmart / home depot.

 

Suggestions?

[DrDNA]

I strongly suggest avoiding electricity.

 

You might try:

-use a stronger acid. eg, muratic acid or phosphoric acid....either of which can be purchased at a hardware/home improvement store....commonly used to clean concrete driveways/sidewalds or tile.

or

-hydrogen peroxide (an oxidizer) from the drugstore

 

In all cases do in well ventilated area (eg, OUTSIDE) and use rubber gloves and eye protection.

 

Heat increases the rate of most all chemical rxns, including oxidation.....but USE WITH CAUTION, esp around acids and oxidizers.

[dwrighto]

Are you suggesting mixing the bleach with muratic acid?

[Cap'n Refsmmat]

That would probably release chlorine gas, which would not be a good thing. (Chlorine gas will attack your skin and lungs.) If you want to try that, try it in a fume hood or something that will otherwise protect you from the gas given off.

 

I don't really know how effective it would be -- just saying that it would be dangerous.

[big314mp]

A salt water + small amount of electricity combo should corrode the steel quite well. That combo is the bane of coastal boat owners...

[gonelli]

A salt water + small amount of electricity combo should corrode the steel quite well. That combo is the bane of coastal boat owners...

 

That combo is essentially what you would need for electrolysis. Setting it up with the steel as the anode would allow for fairly fast rusting, as long as the current isn't too low. Around 1 - 2A would be alright, I think.

 

Only thing is you need to make sure the Fe2+ ions come in contact with oxygen, so if the area to be rusted is just at the surface of the salt water it would be better.

[nitric]

the HCl + NaClO would corrode the steel blazing fast(maybe a hour) but i would not try it unless you outside and doing <100ml total solution after mixing. Since Cl2 is an amazing oxidizer that's why it would corrode so quickly(especially if it was heated) and if you were going to heat it i would suggest using only 10ml or less of combined solution

[max.yevs]

try to add an oxidizer to the acid, like nitric suggested, as it helps pull the hydrogens off tha acid to react faster.... (vinegar plus hydrogen peroxide can dissolve copper)...

 

if you have liquid bromine available, that might be worth a try

 

 

 

Also i've found that 3% hydrogen peroxide by itself makes short work of iron, even more so than chloric acid...

[DrDNA]

Are you suggesting mixing the bleach with muratic acid?

 

Hell no!

[max.yevs]

actually bleach with hcl works pretty well, free chlorine is much better than chloric acid...

 

but don't do it inside, quite a bit of chlorine gets generated

[DrDNA]

actually bleach with hcl works pretty well, free chlorine is much better than chloric acid...

 

but don't do it inside, quite a bit of chlorine gets generated

 

acid and peroxide work well/fast and do not generate such dangerous gases....but don't do inside either

[Kardia]

If you're not in a real rush, bleach can rust in a few days in a safer way than chlorine.

[hermanntrude]

a bomb would do it too :0)

[Theophrastus]

Based upon the size of your sample, I know that the corrosion process speeds up greatly in a pure oxygen atmosphere, so if you place your metal in a large flask of oxygen, you should quickly attain the necessary corrosion. I agree with using peroxide, or some other oxidiser, as in theory, it ought to work quite well, though I, myself have never tried it. Cheers!