Hello all

What's the best product to use for under sealing a normal car, waxoil is an option but what others are available ? black stone guard ? any others

Thanks

Over a good surface?

Or trying to hide rust?

I have had excellent results with Dinitrol. Very thin ML to treat seams/box sections/anything that may have a bit of surface rust, and then their thick and tough underbody wax on top where needed. Done about 8K on my spitfire, through europe a few times, trackdays, all weathers, and it is still surviving in the wheel arches, so head and shoulders better than waxoyl.
I think Bilt hamber do similar high quality stuff.

on a good surface with light rust, how is Dinitrol applied ?

Aerosols, or if you have a compressor, use a shultz gun/lance