Paint & underseal for wheel arches & underbody?
 

I'm trying to decide what paint to get for the inside of the wheel arches (behind the liners). The car is Zircon Silver and the same colour appears to have been used for the wheel arches, then some sort of silver-grey underbody protection sprayed on top of that.

What does everybody else use for the wheel arches and underbody?

Btw, I don't have access to spraying equipment. I'll be putting Bilt Hamber Dynax UC or UB on top of whichever paint and underbody covering goes on.

I used to use Hammerite but the modern stuff is pants compared to the original (H&S gone mad!). I would suggest a visit to a boatbuilders store. Their stuff has to cope with being underwater and the seaside folks have to be under salt water. As you say, once done, some Bilt Hamner as an overcoat should be belt and braces.;)

I put Aquasteel on everything then coat with Dynax UB:cool:

I simply sprayed our local super-market underbody spray over just about everything I could see that might need it.

Two years now and no sign of deterioration. Your spray on top of what's there should outlive the rest of the car.---:D

I have just finished waterproofing my slightly worn flashing on my roof with Bostick roof repair paint and wondered whether that would be any good on these sort of areas (where no stone chippings will affect)? It dries to a rubberised finish and is obviously totally waterproof.....just a thought!! :)

ps agree re hammerite, rust will appear after a few months, 2 coats on my rear arms didnt stop the rust for long!!

Por 15 seems to be the product that has superseded Hammerite, once dry it seems to be almost bullet proof.

Once opened it seems to go off in a few days so don't go buying more than you need.

Just my two cents:

I'd be wary of "painting" any chassis/body parts underneath the car or in the wheel arches, unless you're going to to back to bare metal everywhere and properly prime/paint the whole thing.

If every track of rust hasn't been completely removed, painting over it will likely just create a rust trap, which will allow it to spread underneath the paint/sealer unseen - before breakout :O

As it sounds like you're going to be very thorough and keeping the car indefinitely, I'd be inclined to go the route of removing as much surface rust as possible, then using fe123 or BH Electrox just to be sure, before treating the whole area with Dynax UB or similar. This rust-inhibiting, waxy finish can then be touched up or manipulated as needed every year or so.

If you're looking for 5 or 10 year protection, however, I'm sure any of the 3M rubberised undercoats or POR15 etc. will probably keep things looking decent for the foreseeable (without any real "maintenance").

Don't think there's any one-stop shop for rust, I'm afraid (find it; fix it!) :)


Good luck,
Karl.

Kurust then a good red oxide, the top coat can be anything following that.

Thanks for all your suggestions chaps.

There's surprisingly little rust on the underside of this car now all the bolt-on-able bits have been taken off the rear end (everything is off except the fuel tank). My plan for this year is to sort out the underbody all the way from the rear crash beam to the rear edge of the undertray. In spring next year I'll do from the front crash beam back to the rear of the undertray.

All of the rust spots I can find on the underbody are either where there's a spot weld, or where there's a bolt hole or a drainage/vent/access hole. I need to scrape away the factory coating around these spots and take the rust back to bare metal. (NB. None of the rust spots are serious - it's only surface rust on spot welds and around the rims of holes).

I already have 2 litres of Bonda Rust Primer and 1 litre of POR15 Rust Preventive paint. Either can be used straight onto bare metal or rust but they're red and black respectively so I'll end up with a bunch of red or black spots. The question is what to put on top of them to make it all uniform. I'd paint the whole thing black (with Manor Coatings Chassis Black) but I'm not sure how black wheel arches will look. At the moment the wheel arches are silver (body coloured) and the rest of the underside is a matt grey/silver/slightly pale brown colour - that's how it left the factory.

:shrug:

PS. Forgot to say: the fuel tank strap and the curved bracket for the exhaust heat shield are still on. I was going to take those off this morning but it's chucking it down with rain at the moment. The tank strap is being replaced by a stainless steel one and the curved bracket will be sandblasted & repainted (ditto the 3 tunnel braces). The fuel lines have all been replaced by copper so they're fine.