Is undercoat needed over zinnser bin?

[Adam78]

I have just sanded down some skirting which had a water based gloss on and whilst sanding/scraping the water based paint and whatever was beneath has flaked off in large areas revealing bare wood whilst other areas the paint remains tight.

I was thinking of using bin primer to seal the bare wood and then give an entire lick of pain over all the skirting with bin primer again but bin primer is quite expensive.

Is this the best approach?

Also do i still need an undercoat on top of bin primer before applying a top coat?

I'm thinking of dulux or johnstone satinwood topcoat water based as I need the skirts done and cured fast.

Any cheaper primers paints to achieve a uniform look and ensure paint doesn't peel off and job completed in quick time?

Any advise appreciated.

 

[sxturbo]

Bin is the undercoat.

Just paint whatever you want on top

Spot prime where the paint is chipped(I presume you've sanded the edges of the chips down to blend and make a smooth surface).

Then do a single full coat of bin primer, then 2 coats of top coat, might have to do a third coat depending on paint

 

[Wayners]

Over the BIN with acrylic primer undercoat.