Priming zinc plated plasterboard mushrooms

[Comedydave]

Hi,
I have attached my insulated plasterboard to the sloping part of the ceiling with zinc plated screws through 3cm metal discs (which I presume are zinc plated too but the bag they came in has nothing on it!)

I have read a number of posts about rust showing through as emulsion has reacted with the screws due to the skim coat being too thin. My question is: in order to preempt this, what can I paint the discs with? Can I use red oxide or is that overkill? What other sorts of metal primer might suffice?

Thanks very much

 

[JohnD]

the zinc plating gives short-term resistance to rust. In damp or outdoor conditions it will in time go rusty.

If you want extra reassurance, you can use an oil-based primer. A light coloured one will show less through your subsequent paint. I use a Dulux Metal Preservative primer which comes out light grey/beige. Preservative primers are more expensive than most, but a small can will last a long time. Hardware shops often carry minority interest primers by International, in red cans.

 

[Comedydave]

Lovely job JohnD, thanks very much! I'll get me some of that Dulux Metal Preservative primer so.