plywood or mdf

[Dave Fritz]

A friend asked me to put new tops on some old folding tables. The original was MDF but the screws pulled out and everything was coming apart.

Wondering about using plywood instead of new MDF. Anyone have any suggestions?

Thanks.

[Jerome Hanby]

If you use MDF, I'd be tempted to install threaded inserts and smear them with epoxy before you drive them into the MDF. If you don't mind dealing with the edges or the edges don't matter, I'd go with the plywood

[Myk Rian]

Hardboard, (Masonite) would also work. A little lighter than MDF.

[Prashun Patel]

Plywood will be more durable and lighter. Was the MDF laminated? If not, the edges will get beaten up quickly.

I hate to suggest this, but are the folding tables strictly utilitarian? If yes, then perhaps the best solution is a new plastic topped folding table. They're much lighter and more durable for light use, and clean up easier than either of the above.

[Rich Engelhardt]

Hollow core doors work great for this type of thing.
Lightweight - strong and failry cheap.

Just reinforce the areas where the legs attach w/some 1X pine strips glued and screwed (or pinned) to the door.
I drill out pilot holes in the 1x pine, then run some Kreg pocket screws in and snug them up. When the glue dries, I remove the screws - all but the ones where they bite into the wood frame of the door.

If the doors are old reclaimed ones that have a finish on them, I run a belt sander across the door where the 1x plate is to be installed. IME, complete removal of the old finish isn't required. As long as the majority of the old finish is removed, TBII will bond it enough that you'll destroy the 1X pine trying to remove it.

Since it's going to be covered I go cross grain w/the sander.


BTW - plywood will warp unless you crossbuck it underneath - or - use some really good stuff like Baltic Birch.
If you do decide to use plywood - IMHO - you're way better off to use 1/4" stock and a torsion box design.

[Myk Rian]

What type and size tables are you referring to? That would surely help.

[Dave Fritz]

The tables are 2.5 by 6 ft. and are used at a farmer's market. They fold in the middle for travel. He sells jams and jellies so the tables are holding lots of weight. He's tried the plastic and they bend too much.

There's also the fact the old man that started the business bought these tables and they've gone to the market for over 30 years. The young guy that owns it now wants to carry on the tradition.

Thanks for your thoughts on this.

[Prashun Patel]

I'd do plywood, then.

[Jerome Hanby]

You know, with jars sitting on the table, a little bit of a lip might prevent some breakage by making it harder to slide something off the table. You could band the plywood with some thin solid wood pieces and leave it just a little proud on the top edge. Cover the plywood edges and add some utility.

[Paul Johnstone]

Plywood is lighter, more durable and more water resistant. Also holds fasteners much better.
MDF dust is more hazardous than plywood dust, so it's safer for you.

[Dave Fritz]

Thanks for the validation. I'm off to pick up a couple of more sheets of plywood and get the project out the door.

[David Cefai]

It's not very much more work to lip the plywood and apart from the advantages mentioned earlier you will reduce the chance of splinters piercing the user's hands. Getting clean, smooth edges on the plywood is a lot more time consuming. (Sand, varnish, sand, varnish several times)

[Von Bickley]

I can't comment on the MDF. I don't work with compressed sawdust.

[Kevin Stricker]

I would go with HDO or MDO for a waterproof stable substrate. Less likely to warp than VC ply.