Painting over MDF

[Lynda54]

Advice please!
I had some pipes boxed in using timber batten and (I think) MDF. I primed the batten & MDF but when I tried to put emulsion on it reacted with the MDF and would not adhere. It's covered the batten okay.
I then painted on undercoat hoping emulsion would stick to that, but no luck, it just bounced. I then tried to apply PVA to the undercoated surface but that just ran off!

Why won't it stick and what do I do now? Gloss it then emulsion? Or buy a matching colour in an oil based produced such as Satinwood?

 

[TheDec]

What did you prime it with, and applying PVA was a big mistake.

Dec

 

[Lynda54]

I just bought a general primer. The undercoat went over it okay so I don't understand why the emulsion wont. (Someone advised me to usePVA but it was clearly not good advice! It didn't cover anyway so I wiped it off!)

 

[TheDec]

I think that your best course of action would be to sand the area untill smoothe and apply a coat of thinned oil based undercoat and allow to dry overnight, if then any areas require filling then fill them using the appropiate filler and when dry lightly sand and dust off.

If filling was required apply another coat of thinned oil based undercoat, you could use a thinned emulsion if you wish yet in your situation I would tend to go the undercoat route. Regarding your Emulsion thin it down a little and don't apply it two thickly, and in future never ever apply PVA to any surface that you intend to paint.

Dec