Satinwood rejected by undercoat

[iharding]

Hello, I'm painting MDF cupboard doors which were previously plastic wrapped, now removed, so starting from an unfinished surface.

Primed, left 24 hours, lightly sanded, then Dulux professional white undercoat, left 24 hours and lightly sanded, then top coat of Dulux colour-mix satinwood.

The top coat brushes on evenly, then within seconds streaks appear. Best way I can describe it is as if the undercoat has rejected the satinwood along the lines of the brush strokes, like the surface was oily. It looks terrible.

I stopped after painting two doors, left them overnight, and just tried a second coat. It's better this time, but there are still some noticeable white streaks, and I'm concerned even more coats are still not going to completely cover them.

Primer was the remains of a year old Screwfix own brand tin, both Dulux paints bought new a few days ago. All paint thoroughly stirred before use. Painting, and storage between coats, in a dry garage.

Incidentally I painted a patch of the satinwood on a piece of unprimed scrap MDF. It's obviously gone a bit mottled as the surface absorbs moisture, but none of the oily streaking. Have I used the wrong undercoat? Technique at fault? I've painted pretty much every interior surface of a flat and three houses over the last 20 years, including a set of cupboard doors, and never seen anything like this!

Thanks
Ian

 

[sparkwright]

Is your undercoat (and topcoat) water-based or oil/solvent-based?

Water-based paint tends to leave streaks and buble up and nasty things like that.

Oil or solvent-based paint tends to give a much better coverage and a much smoother finish.

 

[conny]

Could it be some of the wrap adhesive leeching through the two bottom coats of paint?

 

[Wayners]

Zinsser BIN is probably best.
Sand doors with 320 grade and go buy a spray can of BIN.
Stand can in bath hot water and shake every 2 mins.
When can is warm spray door. Not s thick coat as opacity ain't great.
Give it 2 hours to dry and apply your top coat of Dulux.

Then decide If your going to spray BIN on the rest or foam roller Zinsser BIN as a bit cheaper

 

[JohnD]

Is your undercoat (and topcoat) water-based or oil/solvent-based?

Just what I thought.

@iharding
What's the answer?

 

[opps]

Hello, I'm painting MDF cupboard doors which were previously plastic wrapped, now removed, so starting from an unfinished surface.

Primed, left 24 hours, lightly sanded, then Dulux professional white undercoat, left 24 hours and lightly sanded, then top coat of Dulux colour-mix satinwood.

The top coat brushes on evenly, then within seconds streaks appear. Best way I can describe it is as if the undercoat has rejected the satinwood along the lines of the brush strokes, like the surface was oily. It looks terrible.

I stopped after painting two doors, left them overnight, and just tried a second coat. It's better this time, but there are still some noticeable white streaks, and I'm concerned even more coats are still not going to completely cover them.

Primer was the remains of a year old Screwfix own brand tin, both Dulux paints bought new a few days ago. All paint thoroughly stirred before use. Painting, and storage between coats, in a dry garage.

Incidentally I painted a patch of the satinwood on a piece of unprimed scrap MDF. It's obviously gone a bit mottled as the surface absorbs moisture, but none of the oily streaking. Have I used the wrong undercoat? Technique at fault? I've painted pretty much every interior surface of a flat and three houses over the last 20 years, including a set of cupboard doors, and never seen anything like this!

Thanks
Ian

At a guess, based on your description, it sounds like you are experiencing "fish eyes". The substrate is rejecting the paint. The paint then retracts and crater like pools are formed in the finish.

https://dengarden.com/home-improvement/How-to-Stop-Fisheye-in-Paint-and-Lacquer

The above is the first link I found and not exhaustive...

I suspect that regardless of which paint you use, if you run your fingernail over the surface, you will be able to scratch the paint off.

IF, that is the case, you probably need to thoroughly sand the whole surface to remove any contaminants. - sorry, probably not what you want to read.

 

[JohnD]

Is your undercoat (and topcoat) water-based or oil/solvent-based?

Still no reply from @iharding

 

[Wayners]

Dulux professional white undercoat is oil

 

[iharding]

Apologies for the late reply. Didn't spot the notification email until just now.

Yes, oil-based undercoat. Not sure about the satinwood, but judging by how much easier it is to clean the brush, I would guess water based.

However, I've since painted another couple of panels, one planed untreated timber with an initial coat of primer, the other furniture board. No problem with either using the same combination of paints.

Going back to the cupboard doors, a second coat gave much better coverage, with just some light touching in needed after that had dried to create an even finish.
Fish-eyes in the first coat caused by contamination quite possible. The plastic wrapping that I removed from the doors appeared to just have been shrunk on with no visible adhesive underneath, but maybe there was a sprayed on layer of something that contaminated the paint. The second layer of satinwood seems to have sealed it in - so far anyway - and isn't easily scratched off. Guess I'll keep an eye on it and see if it starts being rejected over time.

Anyway, thank you for all for replying. Much appreciated