ᐅ Painting Galvanized Metal

Hello!

Since we were just discussing this, I would also like to hear about your experience (I couldn’t find anything online): What actually happens if you apply the second coat of topcoat too quickly when painting a galvanized metal column (equipment: brush and acrylic-alkyd paint in RAL 7016)? The can states surface dry after 1 hour (at current temperatures) and recoatable after 12 hours. But as I said, what really happens if you repaint over the first coat after only 1 hour?

Best regards,
joho78

The two different paints mix together and both lose effectiveness. The topcoat does not provide protection, the color coat becomes lighter or even dissolves. In the worst case, the whole mess runs off.
Just wait the 12 hours or even a little longer.
First coat on Friday afternoon, second coat on Saturday afternoon.

If the metal is already hot-dip galvanized, the paint only serves an aesthetic purpose anyway.

Hello,
I am also about to paint a galvanized post.
I heard that it should not be painted immediately (the galvanizing was done in February).

Is that correct?

Best regards, Barossi

Payday schrieb:
The two different types of paint interact and weaken each other. The topcoat doesn’t provide protection, the color coat becomes lighter or even dissolves. In the worst case, the whole mess might run off.
Just wait the 12 hours, or better yet, a bit longer.
First coat Friday afternoon, second coat Saturday afternoon.

If the metal is already hot-dip galvanized, the paint is only for appearance anyway.

Interesting. And how about if I’m only talking about the topcoat (two coats with RAL 7016)? Could this also affect the appearance, like making brush strokes more visible?

Barossi schrieb:
Hello,
I am also about to paint a galvanized post.
I once heard that it should not be painted immediately (the galvanizing was done in February).

Is that true?

Best regards, Barossi

My deck builder had me apply a primer just one week after galvanizing, and the actual paint a few days later.
He has been working with metal for a long time, so I believe he knows what he’s doing.

If you overlook the repainting intervals for paint too roughly, the following can happen. The new coat dissolves the old one, causing severe smudging. The solvent from the lower layer has not yet sufficiently evaporated, you paint over it again, and the paint remains soft for a long time, delaying drying and curing. Paint is a mixture of resin and color pigments, liquefied using a solvent. The solvent evaporates, leaving behind a dried, colored resin. Acrylic paints work differently; I’m not exactly sure how.

Galvanized surfaces can be roughened with ammonium hydroxide (also known as household ammonia), then paint adheres well to them. Karsten