What the heck is MDO and where can one get it?

[T.J. Mahaffey]

I'm planning to start building a combination tablesaw and router table workcenter. (I bought the plans some time back from Wood magazine online.) Its the nicest workcenter I've seen and I'm looking forward to getting started.

This is what it looks like in their picture:
http://us.st11.yimg.com/store1.yimg.com/I/woodstore_1879_47413812

The plan calls for mostly MDF and what they call "MDO", medium density overlay board. Now, I know what MDF is, but I've never seen MDO. Am I the only one?

Also, I'm planning to replace all MDF with Birch plywood instead. I don't really trust MDF to hold up to fastening long-term. Plywood seems like it would be more durable in the long run. Plus, using birch ply, I can give my workcenter a very nice-looking finish. I say give the shop stuff first class treatment so I might be able to do a half-way decent finish on something that really matters later. :)

[Joseph N. Myers]

From the web, "Called MDO, or medium density overlay, it's engineered plywood with a resin treated fiber applied to both faces. This gives an extremely smooth finish that is easy to paint. In addition it's rated for exterior use, which means it is safe from the elements, insects, or other outdoor hazards, making it a perfect choice for the new deck or porch".

Great stuff. I got 4/5 sheets from a place going out of business for $10/each some 15 years ago and still have a sheet or two left. Turns out cost over $100 and really great stuff especially for a work station. (Could have gotten 20/30 sheets but what did I know).

A high end lumber yard might carry it or order it for you. I would give woodfinder.com a try, they might have a few places for you.

Regards, Joe

[Peter M. Spirito]

MDO is MDF with a "paper" top sheet. It is used almost exclusively by sign painters for exterior signs. It takes a coat of paint very well. And holds up to the weather very well. It is also heavyier and significantly more expensive. The typical 4ft by 8ft "coming soon" construction sign is generally painted on MDO. Fastening MDF can be tricky. I vote for the Birch Ply as it will take a nice finish and Formica the top.;)

[Corey Hallagan]

TJ, MDO will break the bank. MDF will make a really heavy set up. I would make it with Birch ply myself and it won't eat up your blades either like MDF does. That is a nice mobile work center and looked at it for awhile myself. If you do use MDF, go to McFeely's and get the confirmant screws and the stepped drill bit, with glue and the screws it will definitely hold but the birch will be much lighter in the end.

Corey

[tod evans]

tj, i make all my shop fixtures out of baltic birch, spray it with a couple coats of lacquer and wax it. if you`re looking for a product with a little less maintenance then buy odd colored, missordered formica and apply it to baltic. you`ll come in cost wise about the same or slightly cheaper than sign board(mdo) and you`ll have a more workable surface......02 tod

[T.J. Mahaffey]

Thanks for your input, guys. :)

Interesting stuff that MDO. Thanks for clarifying.

Yes, I'm going to build my workcenter out of birch plywood, NOT MDF.
And I'll at least do my top surfaces with formica.
Man, I wish I could start on it this weekend, but I'm headed to the parents' for the weekend. Maybe next weekend.;)

[Jim Becker]

MDO is MDF with a "paper" top sheet.
No, it's not MDF in the core...it's exterior rated plywood. It's a favorite of sign makers. In my area, a 3/4" sheet (paper both sides) costs about $60 from the local lumber yard.

[Howard Acheson]

>> MDO is MDF with a "paper" top sheet.

As Jim has said, that's not correct.

Let me add this about MDO. What many forget is that while it is an exterior rated plywood coated with a resin impregnated paper, the edges need to be tightly sealed if used outdoors. Water will rapidly wick into the wood plies causing them to swell and can cause delaminations.

For most shop projects, you can easily substitute a standard birch veneered plywood. It paints as well as the MDO if you first use a primer.

[Ken Garlock]

T.J., check around for "shop grade" birch plywood. It is far superior to the also-ran plywood that is handled by the Borg. It is not quite up to Baltic Birch, but it is very very good and a lot cheaper. And, it comes in 4X8 sheets:)

I picked up 4 sheets of 3/4" at Austin Hardwoods a couple weeks ago for about $25 each. I think the quantity discount kicks in at 4 sheets. (I paid $24 a sheet for the 1/2" version.)

BTW, I also looked at MDO while I was at Austin Hardwoods. After seeing it, I decided that is was not something I was interested in. What they had on hand was single sided MDO. The back side as so bad, that it didn't even qualify for CDX.

Good luck on the work station.:cool:

Also-Ran: I had a professor that gave breakdowns of test scores the class after the test. It was the normal stuff like 2 A's, 10 B's, 20 C's, 35 D's, and 6 Also-ran. Over the years that has stuck with me. It was like he was giving the list of winners at the race track.:D

[Barry O'Mahony]

Let me add this about MDO. What many forget is that while it is an exterior rated plywood coated with a resin impregnated paper, the edges need to be tightly sealed if used outdoors. Water will rapidly wick into the wood plies causing them to swell and can cause delaminations. Good point. I've used this stuff on some exterior projects, and the edges definitely need priming and painting.

Also, MDO is available both two-sided, and one-sided. It's an odd material to be recommending for an interior project; 'maybe because of the smoothness of the surface.

Any "pro" lumberyard should have some (i.e., not HS or Lowes); or anyplace that sells supplies for sign makers.

[Peter M. Spirito]

You guys are right. And I know better having checked some out at a local sign shop a few months ago.:o I was thinking about using it for a book case I planed to paint. It seemed like the ideal product. Any thoughts on that?

[Ken Garlock]

You guys are right. And I know better having checked some out at a local sign shop a few months ago.:o I was thinking about using it for a book case I planed to paint. It seemed like the ideal product. Any thoughts on that?

Peter, I have heard that any imperfections in the underlaying plywood telegraphs through the overlay. That, along with a price of $58 per sheet, convinced me that I didn't want anything to do with it.:(

[Art Mulder]

T.J., check around for "shop grade" birch plywood. ...

I picked up 4 sheets of 3/4" at Austin Hardwoods a couple weeks ago for about $15 each.
Fifteen Bucks !! :eek:

Try CDN$55 or more here at Rona (like Home Depot) for a 3/4" sheet of birch ply.

Boy, I'd like to find a place around with good stuff at a price near that.

...art

[Jeremy Gibson]

T.J.

I smiled :D when I read your post because I'm thinking about building that very same setup myself. I saw your shop pics on your website - do you have 57" rails on your saw or are you going to upgrade to the longer rails? Mine are 57" so I will adjust the measurements in the plan to match.

As to the MDF vs MDO vs Plywood question I would think :rolleyes: it would be better to have the extra weight of the MDF. I wouldn't want the base moving when pushing a thick piece of stock through or using the router table. It's not like you'll be picking the base up like a jig. Once it's built it should only be rolled on the casters.

Just my .02 cents :D

[Ken Garlock]

Fifteen Bucks !! :eek:

Try CDN$55 or more here at Rona (like Home Depot) for a 3/4" sheet of birch ply.

Boy, I'd like to find a place around with good stuff at a price near that.

...art

OK Art, I should read what I type more carefully.:o It was more like $25 per sheet.

[Art Mulder]

OK Art, I should read what I type more carefully.:o It was more like $25 per sheet.

Well that works better... I'd still like to see those prices here, though, even with exchange!