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I've been watching videos on building workbenches, and there are a lot of varieties, including one video where they glued a couple of sheets of 1" MDF together for the top.

In this coronavirus era, I'd rather use materials on hand, which happen to include some 2 x 10 fir, and a sheet of 1" MDF. I'm a newbie, so I was thinking that I could start with the 2 x 10s as a base, perhaps rip them so they can go over a friend's jointer and be mostly flat (they are currently cupped, up to 1/8"). Glue them up and get them reasonably flat, then put the MDF on top to make it sturdier and flatter.

I do want bench dogs and an inset face vise.

Any thoughts on what the pros and cons of this approach would be? Or stumbling blocks?

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  • One con is it sucks up moisture like a sponge. Wax it well and often ?? . I would incorporate into your design the ability to replace the MDF top with minimal effort.
    – Alaska Man
    May 20 '20 at 22:32
  • One of the nicest things about using MDF is that it's so damn heavy. Your bench will be super heavy and super solid. I have one with two 3/4" sheets split between the top and a bottom shelf, and even under crazy abuse, it does not move or walk, etc. May 30 '20 at 2:16
  • Was the video from Rob Cossman? I know he has a series (might be paid?) about making a beginner bench with an MDF top. It uses a 1" top. 1" is a bit hard to find, so that you already have it is great! If Rob recommeneds it - I don't think you can go wrong. Be careful if doing some serious cutting / milling - that dust is not good for you! It might be flexible enough to flatten during a glue up.
    – speg
    Mar 16 at 16:32
  • Yes, Rob Cosman's video. And I did pay for it. I found 1" MDF at Mayan Hardwoods in Oxnard, California, 40 minutes from where I live. It worked out well. I'm very happy with the bench.
    – Leonard
    Mar 17 at 17:46
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Sounds like it would work fine to me. My first bench was two sheets of 3/4 MDF laminated together and I had no major issues with it. I used it for years and made quite a few projects that I was proud of on it.

There's really only two very minor things that I ran into. When you're drilling the dog holes the center spurs on forstner bits tend to not like MDF. I was able to drill much faster when I had small pilot holes for my forstner bit.

The second issue was that I never felt totally confident with the overhang that the vise was attached to. If I did it again I'd probably back up that area with a batten on the underside to keep it from flexing down.

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    One small con might be that it would be hard to resurface. If it starts to really get beat up, a wood top can be resurfaced whereas with MDF you'll probably be replacing the entire top (though I have no idea how you would do that easily with dog holes.
    – jdv
    May 20 '20 at 18:28
  • 1
    @jdv I have a large bench in my garage with a double-layer MDF top and dog holes, etc. When I need to resurface, which isn't as often as you'd think, I use to "old" top as a template to cut dog holes in the "new" top. Can also swap the top layer and bottom layer around for some additional mileage. May 30 '20 at 2:11
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What are the pros and cons of MDF as a workbench top?

Pros:

  • Relatively cheap.
  • Is already a flat sheet ready to use as a work surface, saving much time and effort.
  • Fairly flat to dead flat right from the start, but, needs good support to stay that way — MDF, like chipboard/particleboard, can sag under its own weight if only supported near the ends.
  • Although the material is sort of friable, it's strong and cohesive enough for use.
  • Uniform texture throughout, so no knots or other hard spots.

Cons:

  • Not as strong or as stiff as solid wood (even pine and other softwoods are stronger in certain ways).
  • Doesn't tend to take screws or nails as well as solid wood.
  • Possibly outgasses low levels of formaldehyde1.
  • Most MDF doesn't take being wet with water well and can swell badly. But moisture-resistant versions are available — called MR-MDF in some markets — which in addition to the moisture resistance are also generally tougher and stiffer.
  • May not be able to be resurfaced properly. By comparison scraping, sanding and even planing the surface of wooden benches to refresh them is commonplace, as and when needed2.

I'm a newbie, so I was thinking that I could start with the 2 x 10s as a base, perhaps rip them so they can go over a friend's jointer and be mostly flat (they are currently cupped, up to 1/8").

Yes, reduce the wood to smaller, workable pieces as needed to process it into your workbench's understructure.

Since you're a newbie, you'll notice that once cut down the wood will exhibit less cupping3.

Glue them up and get them reasonably flat, then put the MDF on top to make it sturdier and flatter.

There is a major drawback to this plan. MDF is dimensionally stable but solid wood wants to change width in response to differences in temp and humidity through the year. The MDF will essentially stay the same size. While you can accommodate for this sort of thing in certain ways it's generally a bad idea to try to directly attach board materials to solid wood once you go past a certain width, perhaps 18-20" you're into an area where the side-to-side dimensional changes of the solid wood are significant enough that you need to pay attention to them.

What to do instead
However you don't need to ditch your workbench dream using this material entirely, quite the opposite.

Using what you have at hand you can make any number of different workbenches of various styles and configurations. At the most basic a single thickness of MDF can work as a top for now, with the plan being to beef it up later, and possibly add a sacrificial hardboard surface as well. If you have enough material you can laminate it now — a full sheet is 8'x4' and ripping this in half yields 2' pieces, and 24" or slightly less is a very common workbench depth.

There are various ways you can use the fir.

~2 inch material can be used directly and make for a very strong, stable bench. Material of this thickness has been used to make many a woodworking bench that has served its builder well, and outlasted them, as long as the rest of the construction was sound.

A more modern take is to rip the 2x10s into narrower strips (into 2, 3 or 4, depending on how thick you want the final top to end up), then face-glue them together to make a top where the board edges become the top surface4.


1 Formaldehyde-free versions are available.

2 But note that some of this work is used to re-flatten a wooden work surface after it has warped in some way.

3 Warpage of all kinds is reduced when pieces are cut to size, e.g. a noticeable bow on an 8' board may yield two 4' lengths each with only a slight bow. In this case your cupping will be far easier to deal with, and result in less loss of thickness, if you rip the boards into two (note: not necessarily right down the centre).

4 This has numerous advantages, but it's a lot more work.

-1

I bought a 4x12 x 8' and cut it into 2 4x12 x 4' I then used 4 6" long 3/4" dowels as pegs, 2 2' lengths of allthread, and glued them together to make a 4x24 x 4' top (ok, 3 1/2 x 23 1/2) I mortise & tenoned 4x4 legs into this and 2x8 runners into the legs It was a bit expensive, about $40 just for the 4x12, but the thing is rock solid. When I built it 7 years ago and just today I planed the surface flat using the sliding router box on rails trick. It worked great for the tools I had at the time, and now is the center of my garage shop along with my table saw.

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    Hi, welcome to StackExchange. How does this answer the heart of the question posed, about the suitability of MDF as a benchtop? SE is all about Answering the Question, and then if and when deemed appropriate giving the OP more advice/recommendations.
    – Graphus
    Mar 14 at 10:34
  • Check out the tour to be sure.
    – jdv
    Mar 19 at 13:22

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