desk design and veneer question

[C & S]

I intend to build a desk for my home and I am considering making the top from a veneered torsion box. I would like to hear it now, if my plan is doomed for some reason. It would be impractical to prototype the construction methodology, so hopefully I can get consensus of thumbs up or down.

A solid oak desk would weigh far too much for me to handle alone, so I intend to build it as 3 components: two "drawer pedestals" and a top assembly which includes the center drawer as well as the uppermost right an left drawers.

Rather than construct the writing surface from solid oak, I am considering constructing a 1" thick torsion box from 1/4 (nominal) luan plywood sandwiching a grid of pine. The box would be veneered and then trimmed with a perimeter of solid oak with mitered corners. I believe that this approach will give me lighter and more dimensionally stable top. I could potentially glue and/or screw the top to the upper drawer assembly without "cross-grain" issues, yeilding an even more rigid assembly.

I intend to make my own veneer in roughly 4" wide "slabs". I did a test run of hot-melt gluing a 1/8" thick wood to a carrier piece and shoving it through the planer. Nothing bad happened :-). I was able to get it down to about 1/32 before the veneer became unstable.

Question 1: how thin does veneer have to be to "act like veneer"? That is not like a solid wood glued to a substrate that will not change seasonally and consequently will distort like a bimetal thermostat.

My second area of concern is with glue. I wonder if this could be done with contact cement. Is there any reason why that would not work? It would seem to me that it would make the process go quickly and not require 37 cauls.

So can this plan work?

Regards

-Steve

[Morris Dovey]

It sounds as if it could work - but if it were my desk, I think I'd replace that 1/4" luan plywood with 1/2" baltic birch because I think it'd sound better and hold up better over time - but then I treat my desks as just another kind of workbench...

[Robatoy]

What will the dimensions of the top be?

[SonomaProducts.com]

[dpb]

C & S wrote: ...

It can, but don't think it accomplishes much to the objective.

The two piece of 1/4" ply plus another 1/16" veneer plus the interior structure won't be much weight reduction over a piece of 3/4" oak veneer ply to start with.

I'd suggest just building the visual thickness by edging a piece of ply as would be typical counter-top construction and using your trim as intended will accomplish the goal far easier.

Contact cement is not suitable for the purpose if you do go that route, btw...

--

[Robatoy]

Contact cement would work fine if he bought the heavy kraftpaper- backed veneer. We do that all the time with excellent results. Those types of constructs we finish with water based finishes as the solvents in other finishes can cause problems around perimeter edges and possible seams.

I would start with a quality slab door and veneer it. And I did say quality. Joint the edges ( if you're afraid of kick-back use mine. *smirk*)

[C & S]

I agree, easier. However, I'll have to drop nearly a C-note for a sheet of decent pywood and then it's a crap shoot as to how well the color and grain will match the rest of the piece.

I appreciate that input ... why do you find it unsuitable?

Thanks,

Steve

[C & S]

I think you have a good point there. I was thinking the upper drawer carcass would stiffen the assembly. But with full height drawer boxes it's easier to hide (under the overhang) any non-co-planerness of the components caused by a 150 year old floor.

-Steve

[C & S]

I'm leaning towards 66" x 38"

[SonomaProducts.com]

[dpb]

Well, that's a consideration that wasn't mentioned. You talked only of trying to reduce weight which you're not gaining much in anyway was the point...

It isn't rigid nor intended for solid wood/wood. As robatoy says, it will work w/ the backed veneer, but that's not what you were talking about.

[Leon]

Well even if weight was not an issue, a decent sized desk will not go through a normal sized door way. I built mine about 23 years ago, 2 drawer units, Center front panel and solid oak top.

Sounds like a lot of trouble, mine is aolid oak and using "figure 8" attachment clips and screws the top can move all it wants through the seasons with no ill effects.

[dadiOH]

1. I personally wouldn't want a desk top made of 1/4" material...sounds hollow, flexes, etc.
2. Time was when veneer was a standard 1/20. There was 1/16 too. Anything

1/8 or less should work fine.

1. Contact cement works just fine, no paper/fiber backing necessary. One

*does* have to be careful with mineral based finishes around the seams (apply first coat sparsely to seal). _____________

Here's another way to apply veneer with regular glue and no cauls...

3/4" ply 3-4" dense foam protective paper like butcher paper veneer sub-strate 3/4 ply

Clamp around the edges of the top & bottom ply to compress foam. The foam will compress less in the center than at the edges (depending on sandwich width) but still plenty to apply sufficient pressure.

[Robatoy]

There are many advantages to paper-backed veneers. The handling, cutting and fitting alone makes it a more usable product. The stuff I get is consistent, excellent quality, and best of all, no seep-through. Contact cement spray (I buy the 20# cannisters, they look like a propane tank, comes with 15' hose and gun.) from 3M in the cans is excellent stuff. No globs will telegraph, making sanding a snap. Contact cement spray is fast. Very fast. I have also used Wilsonart 3000 water-based adhesive, but that stuff is so strong that you HAVE TO use a backer to the substrate or warpage will be serious. Having said that... it is always better to laminate both sides, but...it is seldom done.

[dadiOH]

I agree, it is good stuff; just not *necessary* to use paper back.

They'll learn when their nice veneered piece of wood decides it wants to be half of a bow and arrow :)

[Upscale]

One thing he might consider though, is that veneered plywood comes with the surface veneer in different thicknesses. A better quality (and thus more expensive) veneered plywood would have a thicker veneer on it making for a more usable surface not as liable to wear through when sanding or later when using. The better stuff is *not* to be found at Home Depot.

[Nova]

The oak plywood sold by the Home Depots in my area uses rotary cut veneer which, in my opinion, looks terrible for large surfaces.

[Jack Stein]

You would build 2 boxes for the drawers and a top. This should not be too heavy for anyone to handle unless it was a huge desk.

Most would do either solid oak, or oak plywood. The difference between the weight of Oak plywood and what you are planning would be nominal.

I could potentially

Again, Oak plywood eliminated those issues.

It's not the thickness so much as how you go about it. Plywood is stable because it AWAYS has an odd number of plies, oriented in opposite directions. You would build your top with the same type and thickness veneer on the bottom as on the top, else it could/would warp/split/crack. Again, much easier to just by a sheet of plywood for the top.

You could use contact cement if it were one large piece of veneer. If you are gluing up 1/32" thick strips into a large panel, you can't use contact cement. Seems like a heck of a lot of work to go through all that when you can just by a sheet of oak plywood.

I think it could work, and would be a hell of a learning experience... The easiest, and most expensive is solid oak. Next is plywood with solid oak edging, next would be buying wood veneer and gluing it to a substrate. Most difficult would be milling your own veneer and making your own oak plywood.

[Jack Stein]

HD sells 4x8 sheets of 3/4" oak for $55.00.

[dadiOH]

How do you figure that? Join narrow strips, use veneer tape and glue edges together; when wide enough, lay the whole thing with contact cement. Done all the time.

I can't argue with that :)