How thick for bent lamination?

[keith micinski]

I am going to try my hand at some bent lamination for a tv stand I am going to make. I want to end up with what looks like a C basically from a side profile and it will end up being about 2 to 2 1/2 inches thick. My question is how thick to make the individual pieces so that when I bend them the ends end up approximately half a circle? Could I make them a 1/4 inch thick? should they only be an 8th? I figure before I start the bend, each piece will be about 30 to 32 inches long. Any suggestions are greatly appreciated.

[Jamie Buxton]

Each laminate must be thin enough that it bends around whatever your radius is. Make your bending form first. Then cut a laminate of some thickness and see if you can bend it around the form. If it doesn't bend, cut a thinner one. If I understand what you're proposing, I think you'll find 1/4" will not bend well enough. 1/8" might work.

[keith micinski]

I figured 1/4 inch might be to thick. I will just make them an 1/8th probably.

[Jeff Heil]

I have found 1/16" or so gives more flexibility and the piece appears more like solid wood. That might be important if the finsihed pieces will be visible as you look at the piece.

[Jeff Duncan]

You may find 1/8" to be too thick also, as said test before you cut all your pieces. There are several other factors that will determine how thick/thin your pieces need to be.

What species of wood? Some species bend easier than others.

Kiln or air dried? Some species do not bend as well once kiln dried.

What's the radius of the curve? At 32" sounds like a tight radius so thinner slices!

Will you be steaming the wood before bending? Steaming adds elasticity to the wood allowing a tighter radius than what would otherwise be able.


Without knowing all this information It's difficult to make a god suggestion. Except to say 1/4" will almost certainly NOT bend, and 1/8" is not likely to bend to as tight as it sounds like your after. With the kind of radius I'm picturing with a good flexible wood your probably better off closer to a strong 16th of an inch.

good luck,
JeffD

[Matt Day]

I think I did about 1/16"-1/8" on my first bent lamination try last year and it worked well but I only had to do about a 45 degree bend. I did all of the plys at once which I think was a mistake, I should have tried doing 4-6 at a time I think rather than fighting them all at once. In your case I would most definitely do a couple/few at a time and work your way up to full thickness. Let us know how it goes.

[Greg Wease]

I haven't done a lot of bending but here are a couple of data points:

For a 6" radius bend using kiln dried walnut the best I could do was 13 laminations per inch. Anything thicker was prone to splitting.

For very small shaker boxes in cherry even 1/16" can be too thick even after steaming.

Bottom line, do as previously suggested: start with a desired thickness thin until it survives the bend radius. I use urea formaldehyde and the laminates seem to bend a little easier after they are moistened with the glue.

[Paul Murphy]

...each piece will be about 30 to 32 inches long. Any suggestions are greatly appreciated.
Keith, a 32" piece will have a radius of ~10". At 2" thick, the inner layer will have a radius of ~8". I wouldn't try to do a 8" radius with anything thicker than 1/16" veneers, because with 2" worth of layers you will have your hands full. Urea glue will give you some breathing room, but spreading glue on 32 pieces calls for a roller or wide tape knife with small notches. Wax or tape your form, because there will be squeeze-out!

I did a demilune table with 54" strips and a more gentile curve. I still used 1/16" shop-sawn veneer because it behaves so much better while gluing, and thinner strips spring back so much less. As others mention, thicker strips tend to split on tight radius bends. Oh yeah, it doesn't hurt to have strips long enough to trim 3 or 4 inches after the glue-up.

[Mike Cutler]

Keith

I just finished two bent form lamination using soft maple.
Each ply was ~ 16th to an 1/8th inch, more like 3/32nd.
Following the advice of my boat building buddies, I steam bent the pieces, let them set.Took them off the form labeling each one and then glued them up back on the form in the same orientation they were bent in.
There was zero spring back.

I think Paul is right and that you may have to a sequential glueup. 2" of material being laminated is quite a bit of material to deal with at one single time.
My glueup was only an inch thick and had a radius of 32" with a sement height of 7", and a chord length of 40". A very gentle curve compared to what you are going to do.

[keith micinski]

Rather then trying to do the entire thickness in one shot is there anything wrong with me doing it in two glue ups to make the glue up less time consuming and stressful?

[Paul Murphy]

Rather then trying to do the entire thickness in one shot is there anything wrong with me doing it in two glue ups to make the glue up less time consuming and stressful?
Nothing wrong with 2 glue-ups, just remember the outside cauls or form will have to have the proper radius to match the stock thickness of that glue-up session (ie 9 or 10 inches).