Painting stained/treated doors

[Freeman3030]

Hi,
I've just bought a new house and all of the interior doors/skirting are a pine coloured wood which feels like it's been stained as it's got a kind of glossy finish.
In my last house, the woodwork in places turned yellow, particularly if I had stood something on it.
I read that water based undercoat and gloss keep the woodwork white, so would like to try it.
However before I paint the woodwork I know I'm going to need to sand it back and treat it. The doors are quite knotty so I thought about using Zinsser BIN white Matt primer, would that be suitable to cover up the knotts/stained wood? Then undercoat in a water based paint and top coat in a silk finish water based paint.
Would that work?

 

[opps]

Oil based paints yellow because of a lack of sunlight. Waterbased paints will not yellow because of a lack of sunlight.

BIN will help to seal knots but no product is guaranteed to work. It might be cheaper to apply knotting solution (once you have sanded the existing paint back) if you have no other use for the BIN.

I am not a fan of water based paints so please feel free to ignore my advice. Varnish needs pretty extensive sanding. Oil based undercoat will obliterate the old wood colour far more effectively than any waterbased paint and is likely to provide a better key for the waterbasd finish of your choice. That said, you need to allow time fr the OB paint to cure.

 

[Freeman3030]

Thanks for your help! I think you're right, I'll use an oil based undercoat. I think I may even have some left over from my last house to get me started!

 

[opps]

If you do go for oil based undercoat, you will need to wait a few days before you can apply the waterbased finish. If you apply it too soon, you may get fisheyes in the paint. Fisheyes are effectively craters in the paint caused by the WB pushing away from spots where the OB UC is still releasing solvents. Terebene (an oxidising agent additive) will reduce the wait time. Alternatively consider a cheap waterbased primer such as Leyland Trade acrylic primer over the OB UC. It is thicker than WB eggshell and less likely to develop fisheyes. BTW the Leyland Trade WB primer is the only WB primer that I have come across that sands back easily. It is pants at obliterating colours though. 5L is about £20 at Selco and some decorators' merchants.