MDF Question

[Sean Troy]

Please excuse my lack of knowledge but is MDF strong enough to screw into and glue up like Ply? I was thinking of making my Miter Saw station a wall mounted one with MDF. Any problems with this application? Thanks, Sean

[Jim Dunn]

If it's glued and screwed it's pretty strong but not as strong as plywood to shear forces. Be sure to pre-drill all holes and counter sink both sides to allow for some blow out of the screws going into and out of the MDF.

[Dave Falkenstein]

MDF glues up well, especially using dado joints. Standard wood screws are not typically recommended for MDF. McFeely's sells a "confirmat" screw that works well in MDF and particle board:

http://www.mcfeelys.com/confirmat-assembly

[glenn bradley]

Confirmat screws are the best way to go but . . . I have a rolling worktable that is dado/rabbet construction with glue and drywall-like screws. All MDF except the plywood back panel and some pine for the drawer boxes. Even the false fronts on the drawers are MDF so it's heavy. It has been rolled around uneven garage floors for three years and I have had no joint failures (I figured it get me by for a year or so but it is still going strong).

I used coarse thread screws similar to drywall screws in profile. Drill your pilot hole of a size so that only the screw threads bite into the material. Drill your holes the entire length of the screw (or a bit deeper). Where surfaces meet, I countersink just a smidge so that the MDF doesn't 'volcano' and leave a gap. I used TB II but any good PVA should be fine.

I also chamfer all edges that will be exposed to bumping. Amazingly I don't have any frayed edges on my little worktable and I have not been careful. Sand the rough spots and hit it with Poly, shellac or BLO/wax and you're all set for years of service.

[Mike Marcade]

I would just make sure there is adequate support under the miter saw. With the lack of grain structure MDF is quite weak and sometimes bowes under its own weight.

[glenn bradley]

I would just make sure there is adequate support under the miter saw. With the lack of grain structure MDF is quite weak and sometimes bowes under its own weight.

Mike makes an excellent point. My MDF RT sagged and I would have never expected it with the support frame the manufacturer supplied. I redesigned the support frame with more ribs and it has been great. As Mike points out, just build a web-frame under your large surfaces. I left no more than about 10" any direction of span without support. I would think you could go wider than that; my work table ahs spans of 16" and I have no problem.

[Brian Dormer]

Kreg pocket screws (coarse thread) grip MDF well. And a little glue never hurts. The only downside to MDF is that the edges are kinda brittle - so think about some kind of edge treatment.

[Paul Joynes]

When screwing into the edge of the MDF ensure that you screws are at least 2 inched from any adjacent ends. Screws that are placed too close to adjacent edges will split the panel.

The Confirmat screws are the way to go.

Regards,

Paul

[Sean Troy]

It would appear that saving a few dollars may not be the best choice and going with a plywood might be the better choice. I would rather do it once and have something last. I know MDF has it place but I think i'll go ply. Thanks for all the great input and info.