Question about different plywoods

[Brad Tallis]

Hello All-

I have been asked to build some cabinets for a client and when I went to price the wood, I came across a few different kinds of plywood.

The client wants the cabinets made out of oak. I saw a sheet of 3/4 MDF Core plywood. This was mdf wood with oak veneer on both sides. It ran for $53.68 a sheet.

The other kind was 3/4 Rotary Cut ply. This looked like your typical plywood with the differnet "plys" sandwiched together. It ran for $47.99 a sheet.

I plan on using pocket-hole joinery for the cases and faceframe. So, that is why I am asking this question... Which ply would allow for easier construction? I heard MDF runs the risk of splitting if you use the wrong screw. On the other hand, MDF seems like it would hold the screw better than ply, but I just don't know.

Any ideas here?

Thanks.

Brad

[Andrew Ault]

Brad,

I have not used MDF with pocket screws, however I have used pocket screws with plywood. In 3/4" plywood, a glued butt joint made with pocket screws is very strong. The type of screw used in a pocket hole has a flat head, not tapered like a wood screw, so it does not tend to split the stock apart.

-Andy

[Chris Barton]

If it were me I would go for the rotary cut. Did you notice if the MDF was peeler veneered or flitch cut veneer (which looks like jointed boards put together)? Thats the only reason I could figure MDF core costing more then rotary...

[Brad Tallis]

If it were me I would go for the rotary cut. Did you notice if the MDF was peeler veneered or flitch cut veneer (which looks like jointed boards put together)? Thats the only reason I could figure MDF core costing more then rotary...

Chris-

The MDF was flitch cut. But, the veneer looks so darn thin, I was leary of how well it would hold up during cutting. I wondered if the mdf provided more of a surface area for the veneer to get glued to, so you would see less "tear-out" than with the regular ply which has more "surface voids" under the veneer.

[Chris Barton]

I have used both and find rotary ply to be stronger and more resistant to tearout as well as better at holding fasteners. Downside is that most commonly available oak veneer ply at that price is peeler cut which is not the most attractive cut. Some cabinet supply lumber yards will carry flitch cut oak but, it will likely cost a good bit more than what you quote. Cherry flitch cut 3/4" runs about $80/sheet in Nashville. My guess would place oak close to that.

[Michael Perata]

Brad

I have had good success using pocket screws to hold MDF to solid/plywood. Not the other way, wood/plywood to MDF.

[Russ Massery]

I would'nt use MDF core to build anything if your going to use pocket hole joinery they don't hold very well in MDF. They hold fine in vernier core. Second the project will end up weighting a ton. I made the mistake on a friends cabinet I built for him. The only real advantage of MDF core in the substrate in flat. Which is great for say birch and other close grain woods.

[John Renzetti]

Hi Brad, There is a European fastener for things with MDF core that provides great holding power. It's called a confirmat screw. A bit fatter than the standard scews. You need to predrill with a special bit and then install the confirmat.
The veneers on MDF core do tend to be much thinner than on your standard veneer core products. With that in mind I would recommend you not use mdf core unless you have a scoring attachment.
See if you can find a product which i believe is called multicore. I've used it. You can also get it prefinished. Multi core has a center mdf core and also veneer ply. You get the flatness of the mdf and the better screw holding ability of the veneer out plys. The veneer tends to be a little thicker than on pure mdf. Also a full mdf sheet can weigh about 100lbs in 3/4" thickness. The multi core weighs somewhat less.
You might also find that the mdf will have a dimension of 48 1/2" x 96 1/2" The extra 1/2" allows for trimming the factory edge to square up the panel and still have enough material to get two 24 x 96 sections or better.
As has already been mentioned you can get rotary, rift or plain sliced veneers. If you want the supplier can also get you sequenced book matched sheets, but expect to pay a lot more for this.
If you are going to cut up a bunch of sheet goods. I highly recommend the Cutlist Plus Silver program. It will pay for itself right away.
take care,
John

[Don Naples]

Brad: You might also look at some prefinished plywood for interior panels if applicable. It does not add much to the cost, makes the cabinet looked better, and can save you much time.

[Brad Tallis]

Hello Fellow Woodworkers...

I knew I would get the expertise I needed here. At first, I was leaning toward using the mdf core ply, but after hearing all of your replies, I'll definately use the regular ply. My biggest concern with using the MDF was how darn thin the veneer was. It looked like just sneezing on it would have caused it to splinter. :eek:

John, thanks for your idea of using the Cutlist Plus program. I use our own CAD software (I work for CoCreate Software, www.cocreate.com (http://www.cocreate.com)) to plan out all my projects and then I create my own "cutlist" by placing the 3D parts flat on a 4x8 3d part. (see images). I have found this saves me a lot of time because I am "building" the project in the cad program so I can visualize how the pieces will fit together, which order they need to be cut, etc. It also saves a lot of wood because I can "squeeze" as much of the parts into each piece of wood.

Brad

http://home.comcast.net/%7Estarjumper/images/cab01.jpg

http://home.comcast.net/%7Estarjumper/images/cab02.jpg

[Jim Becker]

My good friend Russ builds almost exclusively with MDF core veneer sheet goods and his work is both outstanding (he's more anal than I am...) and durable. Modern glues combined with thoughtful rebates, dados and grooves do the trick. He also edgebands before assembly and you'd be hard pressed to tell the sheet stock from solid stock. One other nice thing about the MDF core...it's very consistant in thickness.

As to the veneer...I don't particularly prefer rotary cut veneers. It just doesn't look like boards! Using sheet goods can make cabinetry easier and faster to build, but the end result should always look as good as it can...in your eyes and more importanly in your customer's eyes. Picking the right material is part of that since it's the first step in the finishing process.