Stone Chip or Underseal

[Firefly]

What have people done with the under side after taking it back to bare metal underseal or stone chip.

[James k]

A few years ago I had my chassis redone by the Morris Minor workshop. Stripped back to bare metal, extensive replacement of sills, crossmember and other bits, primed and stone chipped. They also put a light mist of dinitrol waxoyl style stuff over it. It's held up perfectly so far, being driven every day in all conditions. I've sprayed a light coating of dinitrol on any bits that have chipped (very very few) and so far, no rust.

I think underseal has a bit of a bad reputation as when it fails, it traps moisture underneath but hides it from view until it's too late.

[ManyMinors]

I think the most important thing of all, once the rust has been removed as much as possible, is to apply a good coating of an antirust primer. Neither stonechip nor underseal should be applied to bare metal.

[stuffedpike20]

Rob T used to advocate smoothrite paint.

Can you paint smoothrite straight on top of etch primer?

[panky]

I think you need a coat of something else to seal the etch before a top coat, epoxy primer would be a good choice. Personally I'd use exoxy primer then a coat of chassis black enamel as it's not as hard as Smoothrite so less likely to chip. Then finish off with a decent spray on wax, I use Bilt Hamber Dynax-UB which can be purchased with a lance to get into the chassis rails if needed.

[King Kenny]

Never use underseal. It hides more than it helps.

[kevin s]

I paint it with an epoxy primer, seal the joints then stone chip then a gloss topcoat finally if it is to be used in the wet a coat of bilt hamber underboy wax.