Conflicting Info

[Pappy]

Without going into the reason, I want to create a coat of rust on some wheels I stripped. 2 formulas surfaced that can be made from common household chemicals.

4 parts white vinegar
1 part hydrogen peroxide
1/2 part salt

or

4 parts hydrogen peroxide
1 part white vinegar
1/2 part salt

At least the salt is the same.....

[Black wallnut]

What about a test by using teaspoons on mild steel? Do we have a chemist amongst us?

[Tom Slick]

I would think he more acid (vinegar) the better. Muriatic acid alone makes steel rust very quickly.

[LCHIEN]

offhand
vinegar = C2H4O2
Hydrogen peroxide = H2O2
Salt = NaCl
rust = FeO and Fe2O3 (most common among many others)

basically you need a reaction to add a bunch of oxygen to the iron where there was none so you need oxygen rich compounds.

Water is stable and wants to be H2O, so I'd say that using a lot of peroxide would allow two peroxide molecules to combine and make one water molecule with a resulting free oxygen molecule to make into rust. The other items are not part of the final product but probably are catalysts and donors. Possible other stable common compounds resulting from this soup mix: NaOH, HCl, CO2,, maybe Cl2 gas... Chemistry was not my strong point but the acid is probably to get the iron into solution and the Peroxide for the extra oxygen it brings to the game. The most important thing is that at the end of the party you end up with the same quantities of molecules of each kind that you started with, just going home in different cars, so to speak.

I think in reality that the proportions can vary quite a bit as Peroxide is seldom sold in 100% (usually 3%) solution form and neither is vinegar 100% (more like 5%) acetic acid.

[Pappy]

Both mixes were using 3% H2O2. The vinegar I have is 9%.

Since I have 2 gal of vinegar on hand, I will try the first one to see if it works.

[jdon]

Either formula should work. As Loring mentioned, the hydrogen peroxide provides the oxygen. A low pH (acidic) enhancing the rate of oxidation, and, having lived most of my life in snowy regions, I can attest that salt accelerates rusting incredibly.

[Stytooner]

South Alabama humidity works very well. No chemicals.

Of course, here we do have salt in the air from the Gulf, so I guess that does count.