Replies

1. 
   byhammerandhand | Jul 31, 2002 07:51pm | #1

   I am currently reading "The Furniture Guys Book"   One of the upcoming projects is exactly such a table.  I'll take a look tonight and see what they have to say about it.

   Added: Sorry, no real ideas on how this came put together.

   
   

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   Edited 8/1/2002 1:02:16 PM ET by KMEALY

1. 
   DaveEsposito | Jul 31, 2002 07:59pm | #2

   Thank you!

1. 
   AlanTurner | Aug 01, 2002 07:05pm | #9

   I had to make an arch top door casing for an interior entry door.  From a cabinet shop, I got 2 strips of 3/8" very flexible plywood.  The theory is that you attach one of the very bendable strips (in your case, the side) probably to the torsion box construction, and then apply glue all over the first strip and attach the second strip.  Air nailing with staples is good.  When the glue dries, the curve is quite strong and stable.  Simply apply the veneer over the top in the usual way.  The cabinet shop uses this material for curved doors, etc., and the roughness of the bendable plywood does not telegraph through the p-lam.  This shop does primarily p-lam cabinets, vanities, etc.  Not terribly high-end, but the curved sections that I have seen of theirs is just fine.

2. 
   Jamie_Buxton | Jul 31, 2002 08:50pm | #3

   I've done torsion boxes with curved edges.  They're not much different than ones with straight edges.   I'd start on your kidney-bean top by rough-cutting the skins -- the top and bottom.  Then I'd make the edges.   These edges will be structural, rather than finished, so you can make them out of anything you like.   My plywood supplier stocks MDF sheets which are kerfed on the back side.  The stuff bends easily, and would do your job.   If you can't find that, you could stack MDF and bandsaw the shape.    For the core, I use plywood slats standing on edge.  Each slat runs the full length or width of the box, and is slotted to pass by the slats running the other direction.  After you get the box assembled, then you apply the formica.   I'd do the edges first and the top last.  

1. 
   DaveEsposito | Jul 31, 2002 10:49pm | #4

   Jamie,

   Thanks so much for your reply. The process is becoming clearer, but a couple of questions if I may:

   How do you actually attach the sides to the top and bottom. Do you use the top and bottom as the form for the edges? Could you give me a little more detail please...

   My guess is that you cut out your top and bottom  then create your core, then glue the top and bottom to the core, then apply the sides. Is that a workable sequencing of the process?

   Thanks for filling in the blanks...

   Sincerely,

   Dave Esposito

1. 
   Jamie_Buxton | Aug 01, 2002 01:38am | #5

   David --

   Answers...

   I just use glue to fasten everything together. I've seen pictures of people using staples to tack parts of the core together before the second skin goes on, and I cannot figure out why.

   As to whether I'd use a skin as a form for the edges in your case, it depends on how you make the edges. If you use that wiggle-wood pre-kerfed MDF stuff I mentioned, it'd make sense to cut the first skin to the correct shape, and let its edge show you where to glue the wiggle-wood. If instead you laminate MDF up until it is 3 1/2" thick or so, and then use a bandsaw to cut it to the curve you want, then I'd glue that cut-out MDF to the first skin, and use a flush-trim bit to cut the first skin to the MDF. In either case, I'd cut the second skin oversize, glue it on, and as a last step use the flush-trim bit to cut it back to the MDF edge.

   As to assembly order, I glue the edges to the first skin, then glue the core material to the first skin, and last glue the second skin on.

   It is useful to remember that the core doesn't have to be fastened to the edges, and the slats that form the core don't have to form a real joint where they cross each other. The slats and the edges are glued to the skins, and that is what really holds everything in place.

   Another big point is the following. When you have assembled the first skin, the edges, and the core, you'll have a box which can twist pretty easily. Before you glue on the second skin, you must take out any twist. After you glue on the second skin, it is impossible to remove the twist.   At http://www.geocities.com/bawanewsletter/jun02/torsionbox1.pdf there is a handout that accompanied a talk I did for my local woodworking club.  In it is a discussion of the method I like for removing twist.

1. 
   DaveEsposito | Aug 01, 2002 07:08am | #6

   Jamie,

   Thanks again for your generous reply...I'm really looking forward to digging in and putting together a sample.

    If I may be so bold with a final question; When you glue the skin  to the core: How are you applying pressure? Are you using a veneer press, or could you shoot brads through the skin into the core? Ultimately, I will be applying formica to the skin so I'm not sure if brads might telegraph through. If you have any thoughts on this I'd appreciate hearing them...

   Also, I tried the link to you pdf file on leveling the torsion box but that link no longer works...could you let me know if there's another way to get that file?

   Thanks and thanks again!

   Dave

1. 
   Jamie_Buxton | Aug 01, 2002 06:28pm | #8

   David --

    Nowadays I use a vacuum press to glue the skins.  I have a platen for the press which is itself a torsion box.  That's why it is flat, and why it ensures that the torsion box I'm building will be flat.  Of course, I had to build the platen without a vacuum press, which is your situation.  I know of two methods for gluing the skin.  One is a sheet caul -- a sheet of plywood or the like -- with weights piled all over it.  The caul spreads the weight to all of the surface being glued.   The other method is the one you mentioned: brad-nailing through the skin into the core.   That's how I built my platen, and it works well.  The slats in the core need to be wider than they otherwise might be, to ensure that the brads hit them.

    I'll email you the pdf directly.

       Jamie

2. 
   rslatm | Aug 01, 2002 04:10pm | #7

   David..I've never seen anyone use the staples the way you described. The way I learned from Ian "torsion box" Kirby's article  was to staple the core together and glue top and bottom on at the same time.

   Rick