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Rust treatment before paint?

Posted: Sun Jul 16, 2023 3:21 pm
by 911hillclimber
This is about my 2009 boxster.
Driver's side sill has some surface rust locally right at the front that is grit blasted by the front tyres, leading edge of the sill and also a small area (1 cm square) right againt the rear moulding at the end of the sill which I had a go at last year. The sill generally is a bit stone chips both on the stong gard area and to the paint just below the lower edge of the door. So, all in all a bit shabby.

Want to sort the rust out asap.
I have used Kurust for years, and my pot of Kurust must be decades old(!).

Plan is to remove the end covers and remove the rust to bare metal, treat and re-paint (touch up or rattle can, or even have a local body shop fix it.

What is the current thinking to treating the bared metal areas today before re-painting?

Re: Rust treatment before paint?

Posted: Sun Jul 16, 2023 5:40 pm
by hmg66
I’m no expert but wouldn’t you Stabilise/Convert if not getting down to fresh metal as it has to react to the rust?

But if fresh metal you just prime and repaint?

Re: Rust treatment before paint?

Posted: Sun Jul 16, 2023 5:49 pm
by Gary71
Agreed, if you can get it to genuinely shiny fresh metal then just paint with the usual epoxy 121, then prime, then paint.

Any doubt then a wipe with krust/Bilt hammer stuff will catch any stuff you can’t see.

Re: Rust treatment before paint?

Posted: Sun Jul 16, 2023 7:07 pm
by 911hillclimber
I cleaned those areas by paper and then the old Kristie and paint on top of the black surface, but 12 months on its back!
Maybe the old Kurust is too far gone chemically?
Will get something fresh this Time and go from there.

Re: Rust treatment before paint?

Posted: Sun Jul 16, 2023 8:10 pm
by Gary71
I used the Bilthamber hydrate 80, but I think they are all the same chemically.

Putting a layer of the epoxy on just encapsulates everything, fingers crossed that gives it more robustness as well from future damage/stone chip.

Re: Rust treatment before paint?

Posted: Mon Jul 17, 2023 2:40 am
by jjeffries
Any access to a spot media blaster? That would get into the pores of the metal, then a good etch primer, then color/colour.

John

Re: Rust treatment before paint?

Posted: Wed Jul 19, 2023 10:41 am
by Kneeslider
I'm a fan of Bilt Hamber Deox Gel. After cleaning everything up as best you can, apply the gel liberally, then cover with cling film and leave overnight. All the brown oxidation turns the gel green. The following day wipe off the gel and you will see shiny silver metal. Treat this with phosphoric acid, then etch prime. Its long winded, but works.

Re: Rust treatment before paint?

Posted: Wed Jul 19, 2023 1:26 pm
by 911hillclimber
Expensive bottle of Bilt awaited...