Gluing MDF - dont use Liquid Nails!

[Carl Beckett]

Was making a little jig for a chair project ongoing, and needed to fasten some mdf together. Normally I just screw it but this was going into the edge of a narrow piece and it would split for sure if screwed.

So I used Liquid nails. The heavy duty version (903? I believe it was) The formula has changed and they now have a zillion different flavors, and I havent found one that works very well for anything.

So I put it together and clamp it and leave it a couple days. Came back to it yesterday and unclamped it and picked up the fixture and it fell completely apart just picking it up! Dismal! And I didnt even need to scrape the old dried glue off for regluing, it just peeled right off no problem. No adhesion whatsoever!

This time I tried yellow Titebond. (honestly dont know if this will work any better, but it cant be worse)

(Im throwing all of my Liquid nails stuff away - it will just end up causing me grief when I think its doing something but its not). They no longer make the original, which I used for all kinds of stuff. So now a quest for a new general purpose glue (for doing stuff that you really shouldnt be trying to glue together, but that I do anyway)

I know there is another brand that might be promising (it had a blue tracer streak in it when dispensed) - will look for that.

[Charles Wiggins]

MDF does split easily when you're screwing into the edge, but a carefully sized pilot hole can mitigate that problem. I bet the Titebond will be a lot better, particularly if you rough the mating surfaces with a bit of fine sandpaper first. The MDF should fail long before the glue joint. Even if the Liquid Nails had held you probably wouldn't have a good jig. Liquid Nails is designed for building construction applications like hanging paneling and it remains flexible so the joint can expand and contract with movement.

[Ryan Baker]

I use PL Premium instead of Liquid Nails these days. As for the MDF, I'm not sure you can do much better than yellow wood glue. The material peels apart before the joint fails. I wouldn't trust any glue-only joint in MDF.

[Rich Engelhardt]

So now a quest for a new general purpose glue (for doing stuff that you really shouldnt be trying to glue together, but that I do anyway)I've had great success with Power Grab and (if you can find it) Shoe Goo original formula.
I stuck up the motion detector spotlights on my garage - aluminum siding - with Shoe Goo 25 years ago & they're still rock solid.

I use TiteBond II on MDF a lot and it seems to hold fine.
If the joint needs some additional support, I use Kreg coarse pocket hole screws.

[Larry Edgerton]

Carl

I make almost all of my fixtures with MDF. West System is the key. It soaks in about an eigth and changes the MDF into a plastic sheet. I use it for router guides that have to run a lot of parts and with an epoxy coating it does not let the guide bearing sink in. I usually give the whole working surface a coat to toughen it up as well, and if its a keeper I coat the whole thing.

Epoxy sinks into the surface and provides a deep mechanical bond. Try it, you'll like it.......

Larry

[Myk Rian]

I use sheet metal screws for MDF. Drill a straight bit pilot hole first, then counter-sink it.

[HANK METZ]

For little one- off jigs I like to glue and brad them together- either pneumatic or hand driven. The cheapest bench glue works fine for this, and you can brad extremely narrow pieces without rupture or distortion if using MDF.

- Beachside Hank

[Prashun Patel]

I have a bunch of jigs that are MDF yellow glued. It works well enough...

[Jerome Hanby]

I use regular Titebond on MDF and haven't seen any problems. For screwing together jigs, the local BORG sells some screws labeled for use with particle board, I use those of I have them on hand otherwise I use deck screws. Either way, I drill pilot holes and counter sink just a little to get rid of the material that always puckers up around the holes.