Replies

1. 
   RickL | Mar 20, 2006 02:29pm | #1

   That would be David Marks. When referencing something it's best to give more as lots of folks are here to learn and if you dangle a teaser like that it doesn't help. You could also reference the DIY network and do a search for torsion box.

   In google enter "David Marks torsion box episode"

   http://www.diynet.com/diy/ww_materials_products/article/0,2049,DIY_14442_2278181,00.html

   The undisputed master of the torsion box is Ian Kirby who first introduced it FWW many years ago. Don't ask me the exact issue but it was in black and white. Pretty much the definitive article on torsion boxes. If you can find the old Kirby article it's well worth the read. I've seen too many abominations of the torsion box and folks have made it more complicated than it was originally designed as. You can also use honeycomb interiors instead of the standard construction. Thicker interiors is the key to the strength as well as the skins being glued to the interior. I made one that got stuck in an unheated, damp garage for 5 years and it was as straight as the day it was made.

    

   Kim Carleton Graves book on tables gives more on using a honeycomb interior so read that as well.

   
   

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   Edited 3/20/2006 7:30 am ET by RickL

1. 
   jpattillo | Mar 20, 2006 11:36pm | #2

   I looked it up in the FWW index. Ian Kirby's article is in issue #32 (Jan/Feb 1982).This article is available via the FWW Network, just do a search for "torsion box"

   Edited 3/20/2006 4:38 pm ET by jpattillo

1. 
   RickL | Mar 21, 2006 03:00am | #3

   I have the original article myself.

2. 
   DonStephan | Mar 23, 2006 03:37am | #4

   The challenge for me has always been getting a dead flat surface on which to glue up the torsion box. If the box is glued with a twist, it will always have a twist.

   When I had to use clamps, I was limited to a 3' wide solid core door (assenbly table top) that was flat. True, I could lay a 4x8 sheet or two on top of the door, but if I clamped my torsion box to even a pair of sheets, they could twist in the process, making a twisted torsion box.

   Now that I have a vacuum bag, I was confident that I could lay a 4x8 sheet on the 3' wide assembly table top, shim the legs of the assembly table as needed so that winding sticks showed no twist, then lay on top the vacuum bag, grooved platen, ... and the torsion box result would be as flat as the 4x8 sheet.

1. 
   gb93433 | Mar 23, 2006 04:27am | #5

   Hollow core slab doors are an example of a torsion box. Torsion boxes have been used in building contruction and in airplanes for many years.They are also called stressed skin panels.

   Edited 3/22/2006 9:28 pm by gb93433