Replies

1. 
   AlanTurner | Oct 31, 2002 01:38am | #1

   I used bending plywood for the top of the jamb of a 4 ft. arched set of french doors into the master bedroom.  Take two sheets, 3/8" thick, slather with titebond, and nail or clam in place.  When the glue dries, there will be no movement.  Bending plywood is a special item, and I got it from a cabinet shop, but others here can tell you the more specific name, I'm sure.

2. 
   forestgirl | Oct 31, 2002 05:19am | #2

   Here's a thread from awhile back on "bending stock" aka "wiggle wood" aka a few other names:

   http://forums.taunton.com/tp-knots/messages?msg=8067.1

   Should be some sources there.  If you have a plywood specialist in your area, or a cabinet shop, there's a good place to start.

   forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl   ;-)

3. 
   craigmoe | Oct 31, 2002 03:34pm | #3

   I am in the process of using bending ply to create some curved forms for a current project.  If I understood your two potential uses correctly, there is one important difference.  If you are fitting the bending ply into a already curved space (i.e. arched doorway jamb), you should have no problem nailing and gluing the bending ply in place.  If you are using it for an unsupported curve that needs to maintain its shape independently (i.e. chair backs), you will probably want to use a slightly different approach.  To keep this type of bend from springing back, you will need multiple layers of plywood and/or veneer and you will want to use a different type of glue.  You will want to use however many layers of plywood it takes to make the appropriate thickness, and possibly laminate veneer on the front and back surfaces.  Typically, the more layers you use the stiffer your lamination will be, because the glue joints provide the strength.  For example, if you use two layers of 3/8" bending ply and veneer on the front and back, you could also put an extra piece of veneer in the middle of the plywood sandwich to strengthen the curve.  I would also highly recommend a stiffer glue than normal yellow carpenters glue.  In my opinion, the best glue for this application is Unibond (available from VacuPress (http://www.vacupress.com), but you could potentially also use something like weldwood.  Unibond is much less flexible than yellow wood glue, and will create a stronger lamination.  By the way, I have a vacuum press, and if you can buy, borrow or build one, it is the best tool for laminating curved panels by far.  Let me know if you have any other questions. 

1. 
   velzy1 | Nov 01, 2002 01:26am | #4

   thanks, everyone, for the info on bendable ply. that sounds like the ticket for the back of a couch that will have a frame and panel back. as for the chairs, they will be unsupported and the edges will be visible from all sides. I have a commercially made chair that I am trying to replicate, with some alterations, that works very well, folds quite small and is light. I could do it another way, but it seemed like a good challenge to help expand my repitoire. the chair I have has a back and seat that is 1/2 inch thick and has about 7 plys in it. I'm sure it is something that is laminated at the factory.

   thanks again

   pat

4. 
   ian | Nov 01, 2002 01:45am | #5

   Pat

   I recently finished the sleigh bed shown on page 144 of Jeff Miller's Beds book.  This bed has curved head and foot boards made by laminating two sheets of ply inside a bending form.  Jeff shows the bending process in some detail.  I used normal PVA glue and two sheets of 3 ply - there was very little spring back when the clamps were released.   Constructing the bending form was the longest part of the project.   The biggest problem was finding a glue with a long enough open time, ended up using the PVA and working very quickly.  

   For project some years ago, I bought some veneer sliced it to approximately the right width using a cutting gauge then glued a bunch of strips together and bent them in a form.  Used a resourcinal formaldyhide glue.  Had to wait to the middle of winter to get temperatures low enough so the glue didn't set up too quickly.   An appropriate temperature can be a real issue where I live (Sydney, Australia).   It's still spring but predicted temps for the weekend are up to 95 (fahrenheit).

   ian