Decoration on New Plaster

Yes. The paint doesn't wet correctly the surface of the material onto which it is applied.

A primer suitable for zinc surfaces needed to have gone on first.

Does it look like rust stains?

No rust. Can see the shape and galvanised colour of the bead I've never seen this problem before so I think it must be the decorator

Decorator?

It's the finisher who is supposed to use plaster to hide any discontinuities like joints , nail dimples and corner moldings.

Just painting over this is not ever going to hide the metal angle.

How To Finish Outside Corners of Drywall

Kilz covers most anything. It's good for knots in wood, for example, that you want to paint. Good for covering stains that will show-through regular paint.

I'd spray the angle beads with Kilz first, then use the regular room paint.

Kilz won't do any good. You need mud to smooth the discontinuity.

Think Bondo on a car body.

I made the same mistake earlier this week. I made a post mounted mail box out of galvanized sheet metal and painted it without applying an etch primer first. The finish is really bad so I will have to strip it and start again. You will have to clean off all the existing paint, apply a suitable etch primer, re-plaster where you will almost certainly damage the existing plaster removing the paint, wait for the new plaster to dry, and repaint it.

When painting galvanized metal,wipe it down with white vinegar first.

This will etch the surface and give the paint some "bite".

But I agree with others that the corner beads should have a skim coat of plaster,then

sanded before finishing.

It takes practice to get the layer just right.

Too heavy,and the corners edges will chip easily .

Too thin,and no coverage.

You should be able to get one of these in your country.


These types of primer give a tough finish that is hard to scratch even with a tool.
Others have said that the bead is meant to be covered with plaster. Not the type we use! The round corner of the bed is left proud of the plaster by a milimetre or so. It can take knocks better than the plaster. It can even be substantialy dented before the plaster is affected. The downside is that the whole edge needs to be redone if a serious knock causes an unsightly dent.
The flats are glued to the cement render and then plastered over. Is this the style of corner you used?Jim

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