I've heard of people using wood glue, but that seems to be alot more of a hassle than it needs to be. Does anybody have any tips? I try to do it with watered-down wood filler, which seems to work ok, but I don't know if that's the difinitive way to do it or not.
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.
you need a filler which will shrink and expand at the same rate as the MDF -- apply a good sanding sealer, dry per instructions, wet sand, apply another coat, then finish. Zinser works reasonable well.
You can also coat the edges with bondo diluted in a polar organic solvent.
You can also coat the edges with bondo diluted in a polar organic solvent.
I have not tried this before, but the magazine - The Family Handyman - had an article about using (I beleive watered down) drywall compound to do this...
Good luck,
Mark
Good luck,
Mark
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
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.
If you mean an exposed edge, I'm in the veneer camp. Iron on, precut to width type is handy.
For a joint; the new polyurethane glues, of which Gorilla is best known, expand as they cure, ensuring an airtight seam.
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.Curmudgeon said:
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Instead of starting a new thread I thought i'd ask here. Is there anything dangerous about not finishing the edges at all? I have a sub and hi-fi rack in here completely un-sealed, can this pollute the air at all?
For sealing the raw edges, I use the water based Varathane. I like to put a coat or two over the whole cabinet, as MDF tends to absorb water and is not dimensionally stable if it does.
For edges that show, I still use the iron-on veneer.
For edges that show, I still use the iron-on veneer.
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 🙂
I won't argue with that, but I will say that you are probably a thousand times more likely to get run over by a bus than to become ill through the outgassing of MDF. 😉
Here is an excellent LONG thread covering the sealing and preparation of MDF for painting. A lot of quality work and contributions:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=100520&highlight=
http://www.diyaudio.com/forums/showthread.php?s=&threadid=100520&highlight=