I am doing an experiment about rust. I need a way to measure the rust that grows on various nails submerged in glasses of water (and other stuff). My plan is to use an analytical balance, measure nails with no rust and the nails after rusting and the second weight should be more. Then I will compare the difference of the two weights for all the nails, and the one with the greatest difference rusted most. Will this work? And I have a problem: I tested this and a lot of the rust fell to the bottom of the glass. It was very loose and fell when I lifted the nail. So how can I accurately weigh the rust that has fallen off the nail? I can't just weigh the whole glass because the rust is partly made up of oxygen from the water, so the whole glass wouldn't weigh much more since the rust's ingredients (iron from the nail and oxygen from the water) are in the glass to start with.
Instead of trying to weigh the rusted object, you could remove the rust in a non-abrasive way, and weigh how much of the iron or steel is left.
One way that should work is the electrolytic method described at:
http://www.stovebolt.com/techtips/rust/electrolytic_derusting.htm