What do they use?

It`s chassis black you can buy it at paint shops, supercheap, etc. sprayed on with spray gun. It`s great stuff you can fix rust ,cracks,and all sort of damage with one coat. It`s amazing stuff

Rob, looked at a used 4WD a few years ago and it was looking good until I had a look underneath it. Was beautifully finished with a coat of this black gunk and looked in real good nick. Then I accidentaly poked my finger straight through the beautifully painted, but rusted, chassis rail........

Personally will not touch a vehicle that's had that treatment.....

My thoughts exactly MrBitchi, if there is nothing to hide why spray all this bleep every where unless ah ah you have something to cover up like as you said putting your fingers through rust holes or cracks in the floor or chassis rail cracks, same here will not buy if this crap is sprayed everywhere, most of the time it is only car yards that spray it any way not generally some one selling private. Will never buy from a yard unless I buy new only done that three times with wife's car, by my 4bys private and save a bleep load and so far been lucky no major problems with any of them or you can get your self an nrma inspection, worth the $$$$ they have different set up for inspecting 4bys than a normal car. Regards Steve M

Hi Rob

The other thing that is spray on is WD40 or similar, makes the chassis look better, not as good as paint as it does not cover the holes

Ray