Painting MDF

[LCHIEN]

I made a little fixture our of mdf and wante to paint it using a spray paint from a can (enamel)

I hit it with sanding sealer and then tried to paint it.
The first coat looks like heck, the paint is not sticking to the edges (or maybe being sucked in?)

Whats the proper technique?

[DaveW]

A recent shopnotes (I think it was the one with the shop-made drum sander) suggested drywall joint compound (applied with putty knife or fingers, and then sanded when dry) followed by a coat of primer to seal the MDF. Their pictures suggested that spray painting after that worked well.

[cgallery]

A recent shopnotes (I think it was the one with the shop-made drum sander) suggested drywall joint compound (applied with putty knife or fingers, and then sanded when dry) followed by a coat of primer to seal the MDF. Their pictures suggested that spray painting after that worked well.

Yep, I've seen this tip several places now. Works great to seal those edges.

Some people also use Bondo, but that takes more effort to sand.

[jAngiel]

I was planning on trying the half glue half water mixture to seal the edges on the shelves that I am building for my MIL. I read that someone here used it before with good results.

[cgallery]

I was planning on trying the half glue half water mixture to seal the edges on the shelves that I am building for my MIL. I read that someone here used it before with good results.

That makes sense. And it would also strengthen the edges of the MDF, I think.

[25]

Yeah, the end grain on MDF soaks up paint like theres no tommorrow.

[Jeffrey Schronce]

I was planning on trying the half glue half water mixture to seal the edges on the shelves that I am building for my MIL. I read that someone here used it before with good results.

Sizing with the above mentioned mixture works like a champ. From my experience spackle, bondo, joint compound are best for filling voids and particularly getting nice joints. You must be much more careful using those items for edge sealing as opposed to sizing with glue mixture. You can rag on the glue mixture in seconds. The other fillers take more skill, attention and most importantly create MUCH more dust.