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abrown
Rusty Nail Heads

I am getting ready to paint the outdoor trim on my 1840's house and have a question. Every nail head is showing through the old paint with rust. Is there anything I can do to prevent this from happening again when I paint it this time.

Timothy Miller
Re: Rusty Nail Heads

howdy remove all the nails and replace with exterior screws or stainless steel nails.

ordjen
Re: Rusty Nail Heads

Abrown,

Trtaditionally, rusty screw headsare spot primed with an oil primer. Many painters prefer using aluminum paint as the spot primer.

Some of the newer acylic paints on the market claim to stop minor rust. Behr's new Ultra exterior house paint is one. Its film is so dense that it blocks staining. It is also self-priming. You still have to hit bare wood twice, but you do not need a dedicated primer, merely the paint itself.

Removing the existing nails would be an incredible amount of work and would probably result in damaging the smooth surface of the wood. Short of removing, the old nails could be driven in further and then the dimple patched with an exterior grade vinyl patching compound.

Timothy Miller
Re: Rusty Nail Heads

Howdy i was joking... unlse it is a teeny tiny house. opsee just could not help it.

Re: Rusty Nail Heads

Hello Abrown,

Use white cement on old rusty nails and paint them with special paint that are available in the market. I think Ultra exterior is really better for that.

Nestor
Re: Rusty Nail Heads

I'd also spot prime over the nail heads with an alkyd primer.

If the wood were getting wet, the tops of the nail heads wouldn't necessarily rust. The fact that the tops of the nail heads are rusting means that those surfaces of the nails are exposed to moisture.

Latex paints are permeable to H2O molecules (but not liquid water) and it's likely that the rusting is due to migration of H2O through the latex paint to the nail head.

Oil based, alkyd and alkyd based polyurethanes aren't permeable to H20 molecules, so an alkyd film over the nail head should prevent further rusting.

Post again if you want to know how latex paints can allow H2O molecules to pass through the paint film, but not liquid water.

jkirk
Re: Rusty Nail Heads

i completely agree with timothy miller on this. all that was available years ago for nails were bright and galvonized steel nails. for exterior use galvanized works but the coating slowly breaks down and you will eventually get rust streaks on siding.. also if the siding is cedar, the tannins in the wood will react with the product used to protect the nails and this will also cause nail bleeding.

i do a fair amount of siding installs on high end homes. roughly half the homes we do get wood siding or fibre cement siding, both should only be installed using stainless steel. stainless will not rust and it wont react with cedar like galvonized will. we save galvonized nails for roof shingles and vinyl siding

Jay Louis
Re: Rusty Nail Heads

When looking at nails rusting through paint it usually means that both the surface of the nail head is rusted and the underneath side. The only way to eliminate rust bleed from nail heads on the exterior of your home is to remove the nail head completely. There are two ways to do that; 1. Use a nail puller with a claw end to dig into the wood and lift/pry the entire nail out. This leaves a ugly large gouge and is very time consuming. 2. The second method which is much easier and leaves only a small easily filled hole is use the nail head removal drill bit from Nail Head Gone.

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