Molasses is some thick sticky raw/unprocessed form of sugar; is dark/black in colour; is fermented to produce ethanol apparently (wikipedia).
Molasses can be used to treat rust. You could use this treatment for rust that is serious but that does not penetrate 100% the way through the metal. You'd use it in the case where you have a panel that can't be easily fabricated or replaced and isn't a major structural part. An example would be the inside of a bonnet, like in my case, where there was extensive rust on the inside skin of the bonnet (though the rust wasn't visible from the topside).Preparation:
Take the panel down to bare metal - remove any paint. Take the panel off the car and place horazontaly if possible. Use steel wool, a wire brush or the like, to remove loose scale rust.Step one: Pour molasses over the rust, you'll need a thick coating. I used about 2L for the 1/2 square meter of rust that was on the inside of my bonnet. Leave to sit for an a couple of hours.Step two: Take a garden hose and blast the molasses away!!!
Molasses is water soluble but very thick so it will take a fair amount of water to wash it away.Step three: Allow to air dry.
***Note: you can use a deoxydine treatment (after the use of molasses) and prior to painting.
On washing may notice the molasses has stuck to some of the rust scale and peels it away as you wash the molasses off. This is good as you don't want loose scale coming away after your final paint job
I don't completely know the way this treatment works; the molasses does help by mechanically sticking to the loose rust scale and removing it. I'm unsure if there is some kind of chemical reaction, but from memory there is some penetration of the rust by the molasses.
One thing is for sure this process does seem to work very well, my bonnet still looks in very good nick.
I'll post a picutre of the inside of the bonnet at some stage.