Technical Surface rust above paintwork

[Leroypanda]

Guys and Gals what do you recommend for removing surface rust that is on top of/in the paint work? Its located just inside the rear arches near the sills.
Ta.

 

[lambou1d]

No simple or easy answer to this one.
Rust will be under the paint and causing staining over/on the paint - unless they are tiny specs of rust thrown up from the brakes and road surface which can be removed with a clay bar or paint decontamination spray.
Anyway, there's only one way to get rid of rust properly - cut out the rusty metal and weld in fresh. However, doesn't sound that bad in your case so If the rust has just started then you will get away with stripping paint and rust with a grinder then treating with a rust remover/converter before repainting. Unless you get all the rust off or properly converted it'll be back.. eventually.
If you're talking just within the wheel arch itself, I'd get the grinder out with a polymesh stripping wheel, get all the paint and rust off, if you can get all rust off without a rust converter then spray with a cold galvanising paint before undercoating and painting. If you have to use a rust converter then don't bother with the cold galv. Good luck.

 

[The Panda Nut]

Yes. Leaving rust is inadvisable as it will get worse faster and faster asit gets worse!
As it happens I have just done the o/s front of our 2011 car which had lost quite a slab of paint and had rusty edges on the front of the sill beind the front wing overlap.

I took a drill mounted wire brush to it and removed all the loose paint and and then stipped the rust which really was the lightest surface rust, Followed this with a coat of rust converter from Dinitrol and gave it overnight to dry hard. Two coats of etch primer a good coating of stone chip and its now looks like new. I had done two other corners last year and they are holding up well, Just the front nearside to do. I have found the twopack top coats from out local auto paint factors works way better than any paint I have ever used before. I should be able to run the polisher over this tomorrow with some G3 ans hopefully jobs a goodun for a few years. Having a DA polisher does really make paintwork possible as this does make the finished jon pretty well invisible but elbow grease and soft cloths would sub at a pinch. Trick with G3 is to use a moderate amount and then keep polishig until if effectively disappears when hopefully the finish will be properly blended in. Leave each coat a good long period of time to cure before moving on. Be patient and dont try to rush it!
Good thing Ive just taken a photo as Im not happy with the bit by the hole in the sill. Needs a little more stone chip and overpaint. I have not polished this yet so its far from perfect but it will at least keep the weather at bay. Cost about £40 and all materials and wire brush good for a lot more use.

PS the sill grommets are 12mm. I can now order a few more as have a missing one.

 

[Leroypanda]

well last year I sanded this area back to metal, removed the liner and cleared the crud out, waxoyled behind it, put the liner back, rust converted the front of the arch, filled to bring the level up to the height of the ajoining paint and top coated.

This year the rust is back.

 

[The Panda Nut]

Once a car starts rusting you are engaged in a war of attrition. Its a case of keeping on top of it. If you get rid of all the rust and use cold galv spray this definitely helps but getting rid of every last spec of rust is difficult. Ive just had someone clean and waxoyl the whole front end of Daffo so hope it will arrest the rust for a while at least. I now need to re treat both the 2011 and 2014 cars back ends and then start on the newer one the sump guard needs to be repainted in spite of it living in doors and not often going out in the wet. I just dont fancy two days underneath it. Noop was given a good spraying with underbody wax day one so I hope it will protect for a while longer.

 

[Herts Hillhopper]

The line ‘sanded back to the metal’ is worrying. The body shell of the Panda - and nearly all other recent cars - is galvanised after assembly. This means it’s dipped in a tank that deposits a rust-preventing layer of zinc over the steel, inside and out, before it’s primed and painted. Sanding back to bare metal will remove that rust proofing layer.

I can’t remember - have you had the car from new? If rust is appearing in a place like that, which galvanising should prevent, to me it sounds like some damage has been repaired previously. Damage repair also means sanding back to bare metal, and so introduces the likelihood of rust in later years, I’m sorry to say.

 

[Leroypanda]

18 Months old when I brought it, one owner plus FIAT.
Definately no damage in that area at least.