I am making some picture frames from an old table. The table top is oak slats on top of particle board. I’ve sliced the table and trimmed the slices with walnut, and cut rabbets in the frames. Like this:
Prior to adding the trim, the slices are extremely fragile, as the oak slats are held in place only by a few nails (most now cut off) and some drops of very old glue. I dropped one 2 feet and it split into three pieces; they can’t support their own weight if held by one end. The trim, however, takes care of this.
So the cross sections are:
Now, I need to:
- Strengthen the particle board so it doesn’t chip easily.
- Seal it so it doesn’t expand and crumble so much in humidity or if it happens to get damp.
- Surface B needs to be able to hold the adhesive from gum tape, for mounting the contents of the frame. This means it needs to be a bit smoother (the rough surface of ldf doesn’t provide much contact area), not fall apart when wet (gum tape is water activated), and not be weaker than the tape itself (tape does no good if it rips the surface itself off).
I can only really do stuff to surface A and B.
How can I seal, strengthen, and prep the particle board surfaces?
Shellac seems to make it less crumbly but isn’t good enough. Polyurethane soaks right in and doesn’t leave the surface smooth, although I suppose I could do tons of thick coats until it has a resin-filled appearance but that will take a long time and could get messy. The other thought I had was to just smear a thick layer of wood glue all over it, let it dry, and sand/route it flat.
I don’t really want to trim the back if I don’t have to because I don’t want the frame to be thicker and also surface A would be difficult to cover.
What can I do?