rust stains where nail heads.

[alwayscurious]

Hi there. I moved into an older house that's been renovated. Galvanised nails weren't used - so

Unfortunately on the hand rails and fence at the front, which appear to be treated pine, that has been painted: On the fence, the nail heads are rusting and staining the white paint.

On the hand rails, the same, the nail heads are rusting through the filler and staining the white paint.


Aside from painting the whole lot red oxide what's the best way to fix this?

Secondly: I noticed this AFTER I built a second safety rail from the deck down to the ground - and I used normal (non gal) nails. DOH.. So how do I treat the nail heads to stop the rust before painting?

Cheers
always curious

[echnidna]

use an oil base undercoat

[thesupervisor]

in past experiance even using gal screws/nails in cca treated products will cause rust i would only use stainless or them grey scews from bunnings
i think the best you could do is puch the nails in as far as you can spray cold gal in the holes and plasti bond the holes should last a few years

[Skew ChiDAMN!!]

The best way? Pull it all apart and rebuild it using s/steel screws. (Flush plug the ends with dowel if you wanna get fancy.)

Besides that, you can't stop the rust. But IMHO Echnidna's advice is about as good as it gets for slowing it down to acceptable levels... oil-based primer and paint.

[Make it work]

I agree, gal nails will not last in treated pine, something in the chemicals used to treat the timber reacts with the zinc and the steel to cause the metal to be corroded away to nothing in a fairly short time.

The grey coated screws mentioned (class 3) have a polymer coating over a mechanical plating that competely seals and isolates the steel in the screw from the corrosive chemicals.

Stainless is not always stainless so be careful. Most often screws are not 316(marine grade) or 304(GP grade) but 420grade for a bit more hardness. Unfortunately they are nowhere as stainless and you should not use them in a corrosive environment.

The bad news is that if as you suspect it is treated pine and someone has used the wrong fasteners, pushing them well below the surface and sealing the hole with a good putty will only hide the problem for a little while. One day, when the fasteners are corroded away the structures will start falling apart.

If you don't want to pull it apart, drive the nails in and seal but also screw it together as well with class 3 polymer coated screws and then the only thing you will have to fear is rust stains, which can be fixed with paint.

Hope that helps.