9 replies to this topic

[minisilverbullet]

I noticed when I got under the car at the MOT that there were to rust patches on either side of the tunnel. 

 

I was swapping my exhaust today, so I had an opportunity to explore it a bit further. So I have taken the effected ares down to metal and thankfully there are no holes. 

 

I reckon that the cause has been the who bolts which protrude through the floor, these had plastic nuts on them. I can't remember what was there before. Was it maybe a heat shield?

 

Anyway I think these nuts have trapped moisture under them. Or any other ideas? it is very localised and the rest of the floor is excellent. 

 

 

 

​You can see that the metal is a bit pitted. Should I treat this with some rust stabiliser and then some stone chip? 

 

All advice welcome.  

 

Thanks

[sonikk4]

The best thing other than cutting it out and replacing the affected areas is to get the areas media blasted. Then once done etch prime, epoxy prime and stonechip followed by topcoat.

[cal844]

The best thing other than cutting it out and replacing the affected areas is to get the areas media blasted. Then once done etch prime, epoxy prime and stonechip followed by topcoat.

Good advice, personally I'd try a rust eater like Sealey rust remover(less mess and prep) then I'd clean the whole floor then prime the treated areas, stone chip (I use Upol gravitex) then seal it with paint

[Ben_O]

In the short term, you really want to treat the rust and remove as much as possible before priming and stonechipping but in the long term, it really needs to be cut out as Neil has said.

It's always best to fix these smaller issues whilst they are still small issues.

 

Ben

[minisilverbullet]

I have gone over it again with a wire wheel and I am sure I have all the rust cleaned out of it. It is pretty pitted but is clean. 

 

I don't plan on cutting it out and welding in new metal just yet. 

 

No one has mentioned the use of a rust converter - I guess these don't work. 

[AndyR]

If its only pitted, and still structurally sound i would use a rust converter.  Otherwise no matter what you cover it with it will continue rusting underneath.  There are lots of different types, but i prefer straight phosphoric acid (por15 prep and ready for eg.) as its not suspended in anything, often they are suspended in latex and i feel this affects the adhesion of paint to the panel.  Ive even experienced the latex holding water which causes the panel to flash rust after a period of time.

 

Im sure there are loads of other preferred options out there......

 

Andy 

[MikeRotherham]

I would use a rust remover like Deox Gel.

 

Just follow the instructions to the letter even though it seems like a faff.

 

It really does work.

[MiniMoe2008]

I used POR-15 Rust Converter (Link Below) and then primer and rubber paint. Unless you are wanting to do the whole floor, don't buy the whole POR kit. 

 

https://www.por15.co...-Prep_p_15.html

 

https://www.rustoleu...d-undercoating/

[Alice Dooper]

I had exactly the same problem around the heatshield retaining studs. Some areas it was too heavily pitted and I was scared that the stonechip coating would keep a metal moth problem hidden until it was too late.

The other areas what we done was -
1) pretty aggressive wire wheel back to sound area and clean up
2) por metal prep, mainly phosphoric acid that eats away more of the rust and leaves the area primed for the next stage
3) 2 coats of por15. Not the cheapest or easiest to work with but very good as far as I’ve seen. It needs the surface to be clean and well prepared or it doesn’t stick as well in the long run. Note to self - wear and if you’ve ran out go and buy some, otherwise it’s not coming off your skin for at least a week!!
4) stone chip coating. My favourite is raptor. Give the por15 a good rub with scotchbright pads though, the por sets like glass and I don’t think it’s a great surface for adhesion of the next coat.
5) waxoil or Dynax layer.

Though, saying all that and even though it may seem extreme, the best thing is putting new metal in there, especially if it’s heavily pitted.

[FlyingScot]

Deox with taped on cling wrap to hold against surface. Electrox primer then paint.

Seems to work okay on mine.

FS