Forum:
hi guys, ive just been to a farm sale in my area poor old boy was retiring! i bid on a large cattle tub of paint and lo and behold it was filled with loads of hammerite underbody sealer with added waxoil..... i won it all for a £1!! im going to paint my chassy and my wheel arches etc. has anyone done this and is it any good?? ive heard various feedback from folk not all good i have to say! erm, but judging by the amount of salt that they have started to shove on the roads up here im going to need it otherwise i could be wasting away my car very quickly.... any ideas??? (we already have snow....) 
steve.
It is a very good idea but
It is a very good idea but you need to ensure your vehicles underside is spotless before you apply it, and you need to apply it to the inside of every chassis rail or crossmember where possible. Most chassis rust from the inside out.
I would advocate using a hose to wash off as much as possible and get into every void and hole you can, then, while everythings wet and soft, hit it with a jetwash but avoid rubbers on CV and steering joints. Go through every orifice and inside the chassis to remove everything.
If you have a small angle grinder then fit a small (3" / 75mm) wire brush which just screws on and clean small areas with this as it rips any rust and underseal off without clogging, and the brush can be cleaned.
Apply your paint with a spraygun if you have one and lather it on.