MDF preparation for paint & laquer?

[Ruggers]

Hi, i got some 8x4 MDF sheets 22mm thick and i've cut them into wardrobe doors and routered the edges. I've got some Ronseal melamine & MDF paint which says it's a paint and primer in white.What i'm wanting to do is paint them white then give them a few coats of something like car lacquer to give them a high gloss finish. I was wondering whats best to rub the wood down before and inbetween coats of white and the lacquer?

 

[badgerchief]

as it`s m d f you shouldn`t need to rub it down prior to painting the first coat give it a wipe with a damp cloth and allow to dry a fine sand paper then between coats wear a proper m d f dust mask as this stuff is dangerous and i avoid it as much as possible do it outside if you can

 

[makitaman]

You'll need to be carefull with the routered edges as they will be 'fluffier' than the rest of the board. A good way to seal this edge is to brush a 50/50 pva/water mix onto the edges to seal them. Once fully dried rub down gently and then proceed with your normal painting sequence.

 

[Ruggers]

thanks guys, the edges are fluffier like you said, ill try and pva them to seal it better, but ill try a test piece first, someone told me this stuff really doesn't like water and will expand if i get any near it?

 

[makitaman]

You're right about mdf and water (if its soaked). The tried and tested way to seal mdf open edges is pva/water 50/50 mix. This will seal the edge allowing you to lightly sand with fine paper and then paint. If not the open edges will always look rough and cheap.

 

[Ruggers]

Thanks, ill cover the rough edges in a pva mix then i have some of that anyway. Do you reccommend wire wool or fine sanpaper like a 60-80 or something?

 

[makitaman]

First gently sand the open edges with 240 grit paper.
Then apply a 50/50 mix of pva/water, when fully dry cut back again with 320 or finer grit paper and apply a coat of an oil based primer to the edges. When this is fully dried de-nib if required, then apply your chosen primer to all sides/edges. From here on your normal painting method will apply. Make sure you paint all surfaces to avoid bowing.

I've always had good results with Dulux Woodsilk - get a decent brush and the brush marks disappear completely.

Good luck

 

[Ruggers]

Thanks for the great help, im gonna take your advice and now start the job, i got mixed up when i said 60-80 grit, forgot its rougher the lower you go lol,