I always hear people claiming that you must remove 'active rust' from helmets, or 'stabalise the rust' with various products.
Although I am not a chemist, I think it is quite simple: in the presence of a certain amount of humidity, iron will rust, when that humidity is removed, the iron will not rust any more. The presence of rust or not doesnt change anything to that simple equation.
Below is a real case example on an American helmet I have. It was stored 55 years with the chinstrap passed over the brim. The chinstrap apparently captured humidity, causing rust to form (this phenomenon can also be seen on helmets with helmet covers). I got this helmet in 1999, and was told by some collectors that I had to rub the rusted areas down, and cover them with some kind of product: wax, rustol, etc... Otherwise the rust would 'eat up all the helmet'.
However, I did not treat the helmet in any way, as IMO there is nothing uglier then a cleaned up helmet, and the lceaning in most cases only cuases more damage. I did take a photo of the rusted area in about 2000, to be able to control any possible evolutions of the rust.
Below you can see a comparison with about a 6 year interval. I could take the same picture today but was too lazy. The point is to show that the rust did not change at all over six years, even the supposed 'active rust' which is in fact not active at all.
IMO, overcleaning of helmets and other metalic items by collectors has done much more damage over time then any rust would have. Rust is not an infection, it is a chemical reaction that ceases when you remove one of the reactants, the too high humidity.
The only legitimate cases of helmet cleaning I see are on some ground dug helmets with a certain type of rust that cleans off very well with acid, revelaing paint, names and decals. Any type of rubbing should be avoided.
JL
Although I am not a chemist, I think it is quite simple: in the presence of a certain amount of humidity, iron will rust, when that humidity is removed, the iron will not rust any more. The presence of rust or not doesnt change anything to that simple equation.
Below is a real case example on an American helmet I have. It was stored 55 years with the chinstrap passed over the brim. The chinstrap apparently captured humidity, causing rust to form (this phenomenon can also be seen on helmets with helmet covers). I got this helmet in 1999, and was told by some collectors that I had to rub the rusted areas down, and cover them with some kind of product: wax, rustol, etc... Otherwise the rust would 'eat up all the helmet'.
However, I did not treat the helmet in any way, as IMO there is nothing uglier then a cleaned up helmet, and the lceaning in most cases only cuases more damage. I did take a photo of the rusted area in about 2000, to be able to control any possible evolutions of the rust.
Below you can see a comparison with about a 6 year interval. I could take the same picture today but was too lazy. The point is to show that the rust did not change at all over six years, even the supposed 'active rust' which is in fact not active at all.
IMO, overcleaning of helmets and other metalic items by collectors has done much more damage over time then any rust would have. Rust is not an infection, it is a chemical reaction that ceases when you remove one of the reactants, the too high humidity.
The only legitimate cases of helmet cleaning I see are on some ground dug helmets with a certain type of rust that cleans off very well with acid, revelaing paint, names and decals. Any type of rubbing should be avoided.
JL
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