Could use a little project advice here.
I’ve been asked to build a desk using oak or birch plywood. The depth is 30″ and width (length) is roughly 8′.
The back and far right edges will be supported by a ledger board attached to the wall. I am going to attach a 1×1 1/2 oak edge to the face of the board for looks and to reinforce the front. Underneath, the top will be suported by two file cabinets and the far left will have 2 legs attached.
I’m a bit concerned though about it bowing. Should I install a skirt underneath instead or will the front edging be strong enough to prevent bowing.
Replies
Obviously a lot depends on A)the thickness and B) the load. But at 8' I'd be worried too, and would have some reinforcement underneath it.
PaulB
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I would be using 3/4" ply. I'm thinking two file cabinets, one to left and right of the chair would be fine for that span but then to the far left of the left hand file cabinet there might need to be something else supporting it before the legs at the very end. What would you use to reinforce underneath?
Here is a picture of my desk it is 36''x84" built with 3/4'' birch resting on 2 cabinets.
Cabinets are about the same size as standard 2 drawer file cabinets. It is only 7' long but it does not sag yet unless I lean on it.
Warning picture may be large.
John
Very nice. Thats exactly what I have in mind but the left hand side will extend further past the left side cabinet and be supported by two craftsmen style legs. How did you affix the edging? Biscuits or face nail. Plus glue of course.
The edgeing is 1''x poplar I ripped down to 3/4'' x 1'' glued and biscuits. Used the iron on edging for the cabinet bases to hide the plywood edge.
The just sprayed on a laquer finish, don't remember how many coats I used but it is fairly thick.
John
Picture definitly needs resizing. Lets try this one.
John
Do not get the plywood at the big box. It will sag even if it is supported.
Oh yeah, i knew that one already. I never buy anything there. Have a great local yard near by.
Heres what i've done to strengthen spans like that.
In between the plywood and the face board install a piece of flat metal stock. You will have to rip a channel for the stock. If you have the room you could fit a piece of angle behind the wood too.
Family.....They're always there when they need you.
thats a great idea. How do you get the slot in the edge of the board though? Router bit?
Yeah a router would work fine. Either that or a dado blade.
Family.....They're always there when they need you.
Could use some final bits of advice. I've decided to make the top from solid core birch door blanks. Much more sturdy and they are 1 3/8" thick.
I plan to attach a 1 x 1 3/8" oak strip to the outer edges to finish it off nicely. Should I biscuit the oak to the door or just glue and face nail it with a finish nailer and fill the holes prior to staining?
Since the door is thick, I thought the biscuit method might require biscuits one over the other in many spots so the top and bottom of the edging would be secure, however, that might make aligning the edging difficult. Or if I take the biscuit route, should I just biscuit it in the middle of the door and 1 x oak.
I'd use either a long caul or if you have two doors use them at the same time and clamp both at once, maybe just a few brads to keep the edgeing from slipping.
A good way to avoid visable nails is to drive a few 3 or 4 d fin nails in the door edge, then with nippers cut the heads off leaving a fat 1/16" of nail. Dry clamp and the nail will make a divot in the edgeing. Glue it up and clamp. No slip.
If your clamps are too short to both at once, us a 2x6 or 2x4 caul, if it is bowed, good...place the high side to the edgeing and clamp pressue will flatten it out with fewer clamps.
If ya really wanted bisquits, I'd probably just go about a 1/2" down from the top face, remember too close the the surface and the bis. can telegraph. The glue in the slot shrinks and can cause the top to depress just enough, to show up when finish is applied.
Edit: good excuse to buy a 23 ga pinner too..no show pins.
Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
Edited 2/19/2009 4:34 pm ET by Sphere
I like that idea. I think i may just biscuit the door toward the top edge but not to high as you mentioned and then clamp. Maybe add a finish nail on the bottom every foot just to keep it solid? Would that be overkill?If it doesnt line up flush on the top I'll route it flush with a flush bit.
If you're gonna clamp it, do yourself a favor and skip the biscuits...more trouble than they're worth. Glue will hold an amazing amount even if your glue line is less that stellar.
You can line up with top as you clamp on moving one side to the other. Not the easiest to run a router on edge like that.
One other possibility is a "furniture joint". Usually a thin shallow rabbet or small v groove on inside top of edging before glue-up. Leaves a small kerf concealing joint, can be stained dark if you like the look, or if you're glazing, will snag glaze. Adds some depth and detail and has the benefit of concealing movement cracks between hardwood and door.
Everything will be okay in the end. If it's not okay, it's not the end.
Nah, no need to add nails. Like Peter says, the glue alone is often plenty for non-structural joint. Like if the edgeing was say 6" wide and leaned on, I'd beef it up, but for a 3/4" or less? Nah.Spheramid Enterprises Architectural Woodworks
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They kill Prophets, for Profits.
So just glue with the nail stub idea? I like it. It will hold?This is the best place to come for advice. You guys never fail.
I've built hundreds of pcs. of furniture, guitars, pipe organs and what nots, and many, many joints are simply glued and clamped. And I mean clamped, glue minus clamps, ain't usually gonna fly.
I like titebond 2 and 3 and recently have been trying and likeing Gorilla brand white-ish glue, not the poly. I am not a fan of poly unless it is the PL brand liquid or caulk.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
Sorry, when I said "just glue" I meant glue and clamp. For a 7' span, how many clamps should I use? I have 4 pipe clamps right now. Trying to keep the cost of this little project down. Have no income right now.
If you use a caul, which I always do, 4 can do it. A 2x4 or 2x6 is ideal, protects the edgeing and distributes the pressure.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
Will do. Thanks for the tips.
Have fun, whatever ya do.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
ok Sphere one last question and then i'll be on my way. Chamfer or round over to finish the edge? Top and bottom or just on top?
Kinda depends, what have ya for router bits and how "finished" do you want? Contemporary or Kinda soft like artdeco?
With that said, I'd probably go with like an 1/8" roundover to break the edge, it holds finish better than the small sharp breaks of a champher. And I def. would do the bottom edge, and probably go with a 1/4" radius there or a segment of a 3/8TH ..depends on my mood and what bit is sharp and handy (G).
My stuff at home I'll some times just use a spoke shave or handplane, we're kinda Shaker/Country/semi rustic folks.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
I like the shaker/semi rustic too. So you would do different radius for the top than the bottom?
Just a matter of what floats your boat. Really. I just wing it when I am making some things, just because. If it is a commision with working drawings, I gotta follow the plan, if I'm putzing around on my own stuff, I just get creative. If an 1/8" rad. is too little for your taste, you can always take off more. Not versy-vicey tho'.
And yeah, disimilar radius's can be attractive. Any body can make it all sanitary looking and blah, I like a little varity.Spheramid Enterprises Architectural Woodworks
Repairs, Remodeling, Restorations
They kill Prophets, for Profits.
Thanks Sphere. Appreciate the help. I'll get on this in the next few days and post some pics when I'm done.
I was about to suggest just doubling up the ply. Two 3/4" glued together should also eliminate any worry about sage and it would give a better feel as well while in use. The second 3/4 wouldn't have to be hardwood although it may be nice to have a finished bottom side depending on the room and location.
My favorite way of making tops that won't sag is to used "stressed skin panels" (torsion boxes). I have had good luck with just gluing 1/4" plywood to top and bottom surface of foam board, with edges of wood. I even made a table top where I used layers of drywall tape slathered with carpenters glue as the edge material.
Try to cut the depth down to 24". I used some of those steel brackets l9"xl3". Painted them the same color as the wall. Used side by side base cabinets, kicked in on the right (or) left approx. 8" for waste can placement. At 24" no sag (depth). For the elec., and you'll need plenty, I placed the boxes 22" off the floor, helps keep the wiring out of sight. I think 30" is too deep to prevent sag. Are the 30" deep base cabinets going to be custom made?
I'm going with solid core birch doors for the tops now so I dont think sag is an issue any longer.
Have you considered using an inexpensive hollow-core door? They come in the size range that you're considering, are pretty stiff.
Bob Chapman
I use 1 1/4" birch ply regularly to solve this kind of span issue.
In 1994, I built 114 bookcases for a local bookstore using this product, because the architect had spec'd 3'-4'spans. It worked out beautifully, with no detectable sag.
I think Columbia Plywood (?) makes it, and here in the Midwest, Cleveland Plywood, with affiliates in Columbus and Perrysburg, stocks it.
Also Plywood Detroit, which is happy to deal with one-man shops. I buy from them at a little under $100/ sheet, while my local full-service lumberyard pays (I think) about the same price, and has to sell to me on a special-order basis for about $140/ sheet.
Great stuff, and truly liberating! Forget the 1x2 BS, edgeband it, and end up with a cleaner finished product.
AitchKay