Removing a board with construction adhesive on it (1 Viewer)

It's a long story, but I want to remove a board that is glued onto MDF with construction adhesive. I think it was Liquid Nails, but I'm not sure. Will it be possible without damaging the MDF? Any tips? Thanks.

what sort of board, and is damage to the board acceptable?

How large an area are you dealing with?

These are important things to know, but in essence, they're more for convenience.

The trick is to very, very, gently slip something between the two surfaces, and slowly use it to push through the construction adhesive. A long, thin metal spatula, for example. You might go hard against the MDF, the board, or even through the middle of the bond, but the trick is slowly, firmly-but-gently, and patiently. Depending on how much adhesive was used, you might find you need to break the board off to be able to continue to attack the adhesive.

The catch is, you're going to end up with a gunky surface, no matter what. I think most of the solvents commonly available that might break the bonds would also unglue the MDF. You might be able to cut down the remaining adhesive with something like a plane, or even, perhaps, a power-planer -- although you might have to be careful about the stuff getting warm and melting onto a fast-spinning blade. But once you get it close-to-flush as you can, you may have to gently sand it smooth and probably put some sort of filler onto the MDF.

(Note: I've not done the above with wood and MDF. This is based on trying to leave undamaged a plaster or sheet-rock wall while removing a plexiglas panel attached with Liquid Nails. But the same theory should apply.)

Leo

Thanks Leo. The board is 1X3 pine. I do want to re-use the MDF, so damage must be minimal. The MDF is my painted screen for my projector setup. The pine is glued and screwed to the back of the screen, and the screen then hangs on a 1X4 cleat screwed to the wall studs. When I did this a few years ago, I should have used a 2X cleat on screen and wall. I'm now thinking of changing both cleats while I have the screen down. If I was able to get the board off the back of screen, I would then want to replace it with a 2X3.

Would it be possible to simply add another 1x layer onto the existing 1x cleat? That might be easier and cleaner than removing the old board...

Uhm.. By "cleats," I imagine you mean something like what we call "z-clips" -- that set up some overlapping "pockets" to hold things up?

Anyway, the biggest difficulties I'd imagine you having are...

1. residue -- spalled pine from the 1x3 and/or from the construction adhesive (and its removal)
2. possible bending of the MDF panel during the removal process (which might damage the screen coating)
3. it'll be energetic. How will you protect the screen-surface while you're abusing the back side?

But if you just go slow and patient, start at one end and slowly work toward the other end with some sort of pry and some wedges and blocks, and just be careful, you should be okay.

Leo

I thought about that, but it would probably be pretty hard to find a nice straight board for the bottoms to line up exactly. I will try it first to save a lot of work.

You can try this:

Lay the MDF flat. Put 1x4's or something of similar thickness to the pine on either side of the pine board and using circular saw, after careful height adjustment, make cuts across the width every 3" or 4" (you can always use a hand saw). You'll find a short pine piece is easy to remove with minimal damage using a sharp chisel to pry/pound/chip the pine.



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