PDA

View Full Version : Sealing MDF


James Malcolm
07-03-2010, 10:37 AM
What's the best way to seal MDF? New router table going into my basement and I want to seal the cut edges and extraneous holes with something to prevent the MDF from swelling. I was thinking Polyurethane, but what do I know....
glenn bradley
07-03-2010, 10:51 AM
I use a thin shellac and little of it. The ends will soak stuff up like a sponge initially so a heavy application can cause you grief. Multiple light applications; I do 2 or 3 and then sand with 400 grit betweeen 2 or 3 more. At that point I get a smooth edge.

Here's some false drawer fronts for a cabinet that went under my workbench: http://www.sawmillcreek.org/attachment.php?attachmentid=147868&d=1270958216
Scott Holmes
07-03-2010, 11:11 AM
In a word.... Shellac
Don Selke
07-03-2010, 2:46 PM
De-Waxed shellac, I use it on everything I finish as a sealer prior to the final finish which is 98% water base lacquor or urithane.
Scott Holmes
07-03-2010, 6:04 PM
Don,

You do realize that "water-borne" finishes (beer is water "based" e.g. made from water) are acrylic and not really varnish or lacquer; regardless of what the marketing guys tell you on the label...
Gene Crain
07-03-2010, 9:51 PM
Don,

You do realize that "water-borne" finishes (beer is water "based" e.g. made from water) are acrylic and not really varnish or lacquer; regardless of what the marketing guys tell you on the label...

Seal all "edges" with yellow glue. Top or bottom with what you like...

Water borne finishes are not all the same...Crystalac for one...do not thin with water...www dot crystalac dot com. Target coatings work well also

Gene
Ben Davis
07-08-2010, 11:38 AM
What about just soaking it with BLO and waiting (a while) for it to dry?
glenn bradley
07-08-2010, 11:48 AM
What about just soaking it with BLO and waiting (a while) for it to dry?

I used BLO on my laminated MDF benchtop. It worked well but I applied it using many thin coats and a small paint roller. I would avoid soaking as this could lead to swelling.
glenn bradley
07-08-2010, 11:49 AM
What about just soaking it with BLO and waiting (a while) for it to dry?

I used BLO on my laminated MDF benchtop. It worked well but is more functional than attractive so it will depend on your desired result. I applied it using many thin coats and a small paint roller. I would avoid soaking as this could lead to swelling.
Ben Davis
07-08-2010, 7:02 PM
Never had a problem with it swelling. I've used it to make flat surfaces for honing planes and chisels... never swelled and I live in muggy, sticky, humid coastal NC!
Henry Ambrose
07-08-2010, 7:50 PM
Poly is a fine choice for this.