How to glue MDF plates?

[Tom Andersen]

Hi guys,

I'm making the cabinet of a router table of 5/8" MDF. To assemble the MDF on the edges, I may use screws and glue, or dowels and glue. Screws tend to split the MDF and dowels/glue call for a lot of large clamps which I don't have. Any advice?

Regards
Tom

[Michael Ballent]

You should be able to pre-drill for the screws, and I would use the Confirmat style screws since they are designed for man made materials.

[Steve Clardy]

Why not just use glue, and clamp up

[Hal Flynt]

If you use a drill/counter sink combo to "pre-drill", be sure your hole is deeper than the screw and do a small "countersink" on the inside/mating sides of the hole. This is the area where the 2 pieces meet and leaves some place for the expanding MDF material to go when screwing together. (Sort of a dimple on the underside of the face piece and another on the edge piece.) Not to close to the edge either. The narrower the MDF, the grater the tendancy to split.

I often use an wooden hand clamp to stabilize the MDF and help prevent it from splitting when driving screws.

Have you considered dados and rabbits? Glue and brads may work for you.

[Howard Rosenberg]

Rabbets will help you align the edges perfectly.
This'll be helpful if there's any length to em at all.
Depending on what's going on humidity-wise in your area, you can thin out out your WW glue with A LITTLE BIT of water to extend the open time.

Or...
glue and screws will work perfectly too.
Pre-drill.
Countersink.
Shouldn't break out.

You just have to pay attention to lining up the entire length.

Assuming you've got a HD in your area, #6 1 1/2" particle board screws will work just fine.
Everything'll work as long as you keep your drill square/perpendicular.

Steve Clardy's advice is super practical.
Butt joints work great on MDF.
A thin bead on BOTH surfaces.
"Mush" it around to assure good even coverage and create a hydraulic bond.
Clamp overnight.
Finito.

But....
if it were me, I'd go the rabbeted route.

I clamp speed squares to the various members to keep things square while the glue's setting.

If you want to see photos of some of the furniture I've made with only glue and dadoes/rabbets & butt joints, you can check the archives.

HTH
Howard

[Don Baer]

Hi guys,

I'm making the cabinet of a router table of 5/8" MDF. To assemble the MDF on the edges, I may use screws and glue, or dowels and glue. Screws tend to split the MDF and dowels/glue call for a lot of large clamps which I don't have. Any advice?

Regards
Tom

Tom,
I make up for my lack of clamps by using cauls. I've make my own out of scrap maple, they are real easy to make. Nothin fancy just cut a double taper in one side of a board.

[Michael Ballent]

...
Assuming you've got a HD in your area, #6 1 1/2" particle board screws will work just fine.
Everything'll work as long as you keep your drill square/perpendicular.
...
HTH
Howard

Howard, his profile indicates that he is in Sweden :) so I do not think they have Home Depot there, at least not when I visited a few years ago... We are really becoming an international community :D

[Tom Andersen]

Yes, I'm in Sweden. We don't have HD here but we have something very similar (Bauhaus), I guess that it's the same company group in some way. I don't know whether that is good or bad:) . We don't have Rockler here, we could sure use one.

Thanks for all the good advice. I have earlier done as some of you propose, using particle board screws with a pre-drill. I was succesful in about 95% of the cases but it annoys me that the MDF splits in 5% of the cases. Maybe I am not predrilling well enough. Will Confirmat screws be more safe against splitting the MDF edge?

Tom

[Steve Clardy]

I don't use hardly any MDF or PB.
But when I have, and used the confirmat screws, they worked well.
Have to have the special drill bit that goes with the screws.