Moisture durability of MDF cabinet doors vs. maple veneer with MDF core

[Dylan Borcoli]

Regarding lacquer painted, shaker style kitchen cabinet doors. I'd like to better understand the long-term moisture durability of the 1/4" center panel (inside the frame) when it is MDF vs. a paint grade maple veneer with an MDF core. The frame itself would be paint grade maple.

I've had a bad experiences with anything made of MDF. When the finish wears off, or water gets in a crack, the MDF likes to swell up.

I understand the expansion/contraction benefits of MDF, and that it provides a smooth surface for painting.

But I would like to understand if there would be a difference how the lacquer painted MDF vs. the veneer with MDF core would hold up after 10 years on a cabinet that is intermittently exposed to water (let's say for example the cabinet doors right under the sink counter).

Even though they would be painted, I understand that hairline cracks could happen between the frame and panel if it's not primed good enough, which could be a moisture path.

[Kevin Jenness]

I don't think you would see any difference in moisture resistance between the two panels. A moisture resistant interior grade product is Medex, for exterior use Extira is better. One advantage of Medex I discovered recently is it needs little or no sizing on finished/molded edges prior to painting, as opposed to straight mdf. It's good practice to seal the panel edges and faces prior to assembly.

[Curt Harms]

You've ruled out veneer core ply? If you're going to paint it, you could use Birch ply. Is 1/4" water resistant MDF available?

[John Piwaron]

MDF does that. :)

Were it me and there were no other options, given what I've learned about CPES, I might try that. Use that stuff to seal the MDF. CPES is a Clear Penetrating Epoxy Sealer. It appears to be intended for sealing and stabilizing rotted wood prior to applying a filler. What you might do if exterior trim has rotted but you can't replace it. It can also be used to seal wood against moisture.

Be sure to seal all edges and surface prior to installing in the frame.

Since learning of it I've begun using it anywhere I'm concerned with moisture or weather. Paint and varnish adhere to it very well.