MDF vs Plywood for garage workbench

[Daniel Pinsky]

Hi to all:

This weekend I will be tackling a workbench project, which is my first project. I have a couple of questions concerning the project.

1) Because my bench will be living in my garage and I live up in canada, where it's cold for 6 months of the year, should I be using plywood instead of MDF because of the cold and moister?

2) Should I be finishing/protecting my top to protect against the cold and moister. If so, then what should I be using?

Regards,

Dan

[rdjack21]

Ben Socratous said:

MDF is easier to work, and a whole lot cheaper. Also with a decent coat of paint/lacquer it will handle moisture well (I left my bench out in the rain for a week while the shed got re-wired and was fine). The downside is that MDF is not as stiff as the plywood of the same thickness, ergo will need more support than the plywood would. Double thickness 18mm MDF will aliviate that issue, I had a sheet of 25mm sitting in the shed for 2 years so I decided to use that!

*yes I work in metric measurements... deal with it, lol

Around here (Austin, Texas) birch plywood can be cheaper or only moderately more expensive than MDF for the same thickness. For instance at the local BB store 18mm MDF (it is called 3/4 but it is 18mm) is about $29.99 and 18mm birch ply is $36.23. But if you go to one of the local lumber dealers that sale to the cabinet makers you can get a higher quality birch ply for $28.00.

What you have to be careful about when using Ply is that if you finish it you must finish both sides of it or it may/will warp. MDF is supposed to handle not being coated on one side a little better.

[Ben Socratous]

Well that sucks! Yet another thing we get charged way too much for here in Australia :(

I can get 18mm MDF at my local hardware store for around $30/sheet. The same size in plywood is $64/sheet! And to make it worse, that is structual ply, ie a pretty crappy finish on both sides. If I was to buy an A-grade finished sheet of ply from a timber supplier, I'd have to fork out around $120/sheet!!!