Sealing MDF Door Edges

Problem: the rounded-over MDF edges of maple-veneer-faced are sucking in too much stain. Solution: edge sealing with gesso or shellac. March 29, 2006

I am making slab doors out of MDF, veneered front and back with maple. I am running in to a problem staining and sealing the routed MDF edges. They are sucking up the stain and not darkening like I want and when I spray the sealer I am using a lot of coats to get the edges sealed. What is the procedure to get this done quicker and better?

Forum Responses
(Finishing Forum)
From contributor A:
Most guys I know iron some veneer tape on those edges. Your doors won't be very durable otherwise because the veneer edges will be prone to chipping and delamination. I think it is pretty uncommon to use that material without taping the edges.

From the original questioner:
In this case they arenít square edges. They are rounded over. I am not a big fan of the material either, but this is what is going into the apartment complex. On the other hand the same style slab doors were originally put into the home I purchased a few years ago, and it is 15 years old and none of the edges are swollen or chipped.

From contributor B:
Have you tried Shellac or a glue sizing?

From the original questioner:
To contributor B: No sir - please explain. I donít normally work with MDF.

From contributor B:You want to seal off the MDF so it doesn't suck in your stain, and your sealers, opaque and clear coatings. 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. Gesso is used both as sealer and a primer. In other cases a thinned wash coat or two of Shellac is used to seal in the composition wood. Glue sizing ( a combination of equal parts of white glue and water) are also used to seal the MDF so you can apply your toners, stains, glazes, sealers, shading stains, and finally your clear coats to produce better finishes.