Painting both sides of MDF

[starlingwood]

Sorry if asked before I did a quick search. I'm making a big media cabinet with painted MDF carcasses. My question relates to painting both sides. It is necessary with 18mm moisture resistant MDF? If so is it same treatment as face side ie one primer and 2 top coats. Also can top coats be any ol' cheap paint as I plan to use f&b modern emulsion on face side but seems a waste to use on back sides. Thanks!

 

[baldkev]

Personally, for unseen areas like cabinet sides against a wall or another cab, I'd say no. You'll want to do both sides of doors though to help keep any moisture changes more constant between the two faces. ( mr mdf can still warp, especially in a door )
In terms of paint, I tend to do a primer coat in acrylic, which helps the edge fibres swell a bit, then sand it flat. The next couple of coats would ideally be oil based or use a shellac sanding sealer. Otherwise each subsequent water based coat encourages the fibres to swell again.
Some people edge their cabs with a strip of timber