Aluminum foil for removing rust?

[230RN]

I was doing a little reading on aluminum foil for another purpose and came across this little tidbit:

http://en.wikipedia.org/wiki/Aluminium_foil

(About 2/3 of the way down in the article.)

Polishing steel
A simple and inexpensive way to remove rust from and polish steel surfaces by hand is to rub it with aluminium foil dipped in water. The aluminium foil is softer than steel, and will not scratch the surface. As heat is generated by rubbing friction, the aluminium will oxidize to produce aluminium oxide. Aluminium has a higher reduction potential than iron, and will therefore leach oxygen atoms away from any rust on the steel surface. Aluminium oxide is harder than steel, and the microscopic grains of aluminium oxide produced creates a fine metal polishing compound that smoothes the steel surface to a bright shine.

Anyone ever try using aluminum foil for removing rust from guns?  It would appear that since blueing is just a form of rust, it would also remove blueing surrounding the rust spot, but I wonder if anyone has developed a practical technique for this, or actually used it for taking rust off things like tools?

No thermite jokes (the chemical reaction is the same).  Wait, I take that back.  Thermite jokes allowed, but I'm more interested in any aluminum-foil techniques that might have been developed by our half-vast membership pool to remove rust.  From any rusty things, not just guns.

For example, would aluminum powder work (if you can still get it from somewhere)?

Terry, 230RN

(For those who don't know, "aluminium" is the British spelling for "aluminum," and is probably more correct than the Uhmurricun spelling.)

[AJ Dual]

I'm somewhat incredulous about how it breaks down rust by forming Aluminum Oxide, and not just grabbing atmospheric 02 instead.

Although the rest of it seems reasonable, although not much different than using steel wool to remove rust, because the steel wool is harder than the rust, but softer than the steel you are cleaning.

[RevDisk]

No thermite jokes (the chemical reaction is the same).  Wait, I take that back.  Thermite jokes allowed, but I'm more interested in any aluminum-foil techniques that might have been developed by our half-vast membership pool to remove rust.  From any rusty things, not just guns.

I'll be honest, my first thought actually was Fe2O3 + 2Al → 2Fe + Al2O3 + heat.  As much as I hate to break the idea, wonder if you could just add aluminum powder to slag rusty guns during disposal?  Anyone have a gun they don't particularly like and have an interest in mad science?

[AmbulanceDriver]

I'm somewhat incredulous about how it breaks down rust by forming Aluminum Oxide, and not just grabbing atmospheric 02 instead.

Although the rest of it seems reasonable, although not much different than using steel wool to remove rust, because the steel wool is harder than the rust, but softer than the steel you are cleaning.

Actually not all that surprising.  the O-O bond in molecular oxygen is pretty strong (if I'm remembering my gen chem materials correctly).  The question is simply which bond is stronger, the Fe-O bond or the O-O bond.

[MechAg94]

First, I believe aluminum oxide will form very quickly on any aluminum surface exposed to air.  If you mechanically rub aluminum, you wipe off that surface oxide and allow more raw aluminum to form aluminum oxide.  The aluminum oxide does not make a mechanically strong surface layer like say chrome oxide in stainless steel. 

I figure you are really just using the aluminum oxide formed to sand/polish the steel.  I believe aluminum oxide is used as a sand blasting compound in some cases.  I can't speak for the reduction potential stuff.

[AmbulanceDriver]

Thinking about it some more.......   The initiation of the redox couple of Fe2O3 to Al2O3 requires a *LOT* of energy.....  And releases even more....   I'm thinking that Mech may be on the right path if there's anything to it.

[vaskidmark]

Alls I know is that when I drag out some certain kitchen knives with high carbon steel there is a patina of rust if I had failed to properly oil them down before putting them away.

A quick rub with a scrunched-up ball of aluminum foil gets rid of the rust and does not leave little threads like steel wool tends to.

Anecdoate does not equal data, but there you are.

stay safe.

[230RN]

Very interesting so far.

Comments:

1.   Remember, it's specified that the aluminum foil is dipped in water, according to the article.  Which limits its exposure to atmospheric oxygen.  So I guess the only thing left for the Al to grab is the O from the iron or the O from the water.  And that H2O bond is pretty strong --if it were not, you could not pour water into an aluminum pot without generating hydrogen.

2.  

question is simply which bond is stronger, the Fe-O bond or the O-O bond.

Why, the 0-0-7 Bond, of course.  (I can't believe I said that.) 

3.  Anecdotes lead to technology.  Technology leads to science.

4.  I think the "warming" described is probably mostly due to the thermite reaction, not necessarily only the friction.

5.  There's Al powder in the Etch-A-Sketch?  Well, I'll be darned.  I thought it was something like talcum powder or whatever.

[MechAg94]

My thoughts: 

1.  There is dissolved oxygen in water as well.  Also, if you remember your chemistry, water has a lot of H and OH ions.  I don't know how that affects this case though.  I switched to mechanical engineering after trying to take Organic Chemistry.  I hated it. 

2.  Also, wet foil would tend to keep the aluminum oxide from dusting off and keep it on the foil as a polishing agent.  You might get the same result using oil such as with a sharpening stone.  Just a guess. 

[230RN]

OK, OK.  Been busier'n a goat with two peckers.  Machine crashed, running on a backup ancient (and corroded) laptop.  I found out what a time sink computers can be, being without one for two days.

Anyhow, I tried it on a rust-spotted steel can and I don't think it did any better with wet foil than I could have done with Scotch Brite (TM) and fine steel wool.

I also found out my younger son had used the electrolytic process with good results.

Terry, 230RN

[Brad Johnson]

I also found out my younger son had used the electrolytic process with good results.

Terry, 230RN

Electrolytic rust removal is pretty darned impressive.

Brad