How do you "edge seal" your MDF enclosures?

:scratch: Do you mean sealing the cut edge of the MDF where it's exposed to the 'outside world'? Or sealing the edges where they join to other pieces of MDF?

For the first, I veneer, using thick veneer and glue so there's nothing exposed.

For the second, I don't have any gaps to seal.
 

GM

Member
Joined 2003
Greets!

Drywall joint compound or spackling paste is my filler of choice when it's going to be painted or veneered. For more durability, two part epoxy. In some cases, depending on the finish you want to achieve, a product like gesso is applied and then sanded smooth to fill and seal in the MDF: http://en.wikipedia.org/wiki/Gesso It's used both as sealer and a primer. In other cases a thinned wash coat or two of Shellac or similar. Glue sizing (equal parts white glue and water) can also be used for toners, stains, shading stains, glazes, sealers.

GM
 
The process is called "glue sizing." Dilute yellow PVA wood glue with tap water (or spike tap water with yellow glue) until it is the consistancy of chicken noodle soup without the chicken and noodles. Brush the mixutre on and let dry. It will seal the very porous edge of MDF so that the edge will take paint the same way the face will take paint.
 
Curmudgeon said:
For a joint; the new polyurethane glues, of which Gorilla is best known, expand as they cure, ensuring an airtight seam.
That's what I use for edge joints. So I never need to worry about any extra sealing measures. You gotta have pretty good clamps, though, as it's fairly agressive in it's expansion. I use the Selleys version of the same thing.
 
pinkmouse said:

MDF will continue to emit formaldehyde -- as well as terpenes and other volatile organics -- there are low emission MDF's on the market -- but you won't see them at Home Depot or Lowes, however as they are used mostly for architectural panels in new LEED compliant construction.

As buildings become more energy efficient, building owners are being forced to contend with the recirculation of hazardous compounds. People wonder why the smells hang around after lunch (could it be that curry the guy next to you had is being recycled through the HVAC :)