Freshly galvanised gate which I want to paint ASAP. A friend recommended using this stuff.
I've always been led to believe that you need to degrease first, followed by an etching primer (Mordant solution), wash after it's all gone black, allow to dry and then a metal primer before a final exterior gloss.
Am I old fashioned and perhaps not up with the latest paint technology which the friend recommended?
Experienced advice needed, I hate painting!!!!
Don
Best thing is to wait 6 months, then paint.
Next best thing is to paint it today. Unweathered plain zinc is still a better painting surface than almost anything else (except weathered zinc).
Wash it first to remove crud, but you don't need to do any more. You certainly don't need to etch prime on zinc, in fact that's going to be worse than a non-etch.
Donwill wrote in news:8fh0n5F9i9U1 @mid.individual.net:
You are right to be asking this question. I live near some expensive galvanised steel fencing which was erected only a couple of years ago, yet the paint is already flaking off.
Audi (the car manufacturers) on the other hand, clearly know how to do it, because the painwork on their galvanised steel car bodies clearly doesn't flake off, even when pummelled by the elements. Mind you, it's probably baked on at high temperature. Someone once told me that with galvanised steel, the very outermost layer is actually (technically) some kind of gas, and that's why paint doesn't stick well to it. Perhaps some learned person can elaborate/confute this!
Al
I thought galvanising was so as you didn't have to paint! Why pay extra for a process you are going to cover up?
S
Looks nicer?
Cars with some form of galvanising definitely rust rather less than those with just paint did, so the idea of doing both zinc and paint is sane.
For that you have zinc paint or good old red lead, which work just fine.
S
I think many people consider galvanising as a purely mechanical protection (like paint), whereas its action is really electrolytic (hence its name!).
Even where galvanisation is scratched the adjacent zinc does still provide protection to the iron underneath.
The purpose of overpainting is really mainly cosmetic, and to protect large areas of galvanisation.
Often in very exposed places (such as hill-top radio towers) micaceous paint is used for physical protection. The original galvanising is allowed to weather for several months before any painting is considered.
Paint will not take well to fresh galv ... Either leave a year or give it a good wash with strong detergent followed by clean water.
I think the acids & contaminants during galvanizing leave too much surface crud.
Also if you fit gate and leave it a year, by then you will have lost all interest in painting it.
If you are going to use Hammerite ... they produce a specific Galv primer, which cleans & etches the surface.
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