Non-boaty, help with corrosion protection please

[Ex-SolentBoy]

Due to an old leak (now fixed) the galvanised reinforcing strips that form the corners of a pillar in my house have rusted. The rust shows through the emulsion paint.

Is there anything I can do to treat the metal strips, now that I have cleaned the paint and plaster away, or do I have to tear out and replace the strips? I could do that with the plastic type, but it would be a big job that I would like to avoid.

Many thanks.

 

[ProDave]

for covering "stains" emulsion paint us next to useless.

In the past, I have painted with matt white undercoat, the stuff normally used prior to painting with gloss paint. Then emulsion over that. It normally stops all stains coming through.

 

[VicS]

As proDave says the emulsion paint will not prevent further rusting and the rust stains will keep coming though.

If you have cleaned off all the rust it might be worth a coat of zinc rich paint before the (oil based) undercoat

 

[Ex-SolentBoy]

It's quite hard to get all the rust off as there is a mesh web embedded in the plaster that is also a bit rusty. I was hoping to find some sort of anti rust stuff like the hammerite treatment, only suitable for galvanised metal.

 

[VicS]

It's quite hard to get all the rust off as there is a mesh web embedded in the plaster that is also a bit rusty. I was hoping to find some sort of anti rust stuff like the hammerite treatment, only suitable for galvanised metal.

A phosphoric acid based rust remover will attack any remaining galvanising so perhaps not a good choice. I dont know if a tannic acid based rust converter like Kurust or Fertan would be suitable.

 

[Ric]

Spray it with cold galvanising zinc paint

 

[Momac]

I assume you refer to galvanized beading within plaster and not anything structural.
If the masonry has become soaked it will need to be given plenty of time to dry out. If not the moisture within it will emerge through the repared plaster, together with salts if the masonry is brick.
Clean up the rust as best you can. If the rust is thick and flaking you should probably replace the beading. If the rust is superficial I would suggest the use of a cement based render as the first coat. The cement render will neutralise light rust. Then finish using a renovating plaster skim. Do not use ordinary gypsum plaster for the repair.




.

 

[tugboat]

Fish-oil based paint. I use it on my steel boat, brilliant stuff.

http://www.rustoleum.com/CBGProduct.asp?pid=155

 

[Ex-SolentBoy]

I assume you refer to galvanized beading within plaster and not anything structural.
If the masonry has become soaked it will need to be given plenty of time to dry out. If not the moisture within it will emerge through the repared plaster, together with salts if the masonry is brick.
Clean up the rust as best you can. If the rust is thick and flaking you should probably replace the beading. If the rust is superficial I would suggest the use of a cement based render as the first coat. The cement render will neutralise light rust. Then finish using a renovating plaster skim. Do not use ordinary gypsum plaster for the repair..

Thanks for that. Another week of DIY awaits me.