Cypress bent lamination?

[Eric DeSilva]

I'm building some Adirondack chairs, and the plans have an option for a rocker, which my wife took a shine too. I've never liked rockers with the rockers just cut curves; something worries me about the strength. So, I started thinking this might be a good excuse to try bent lamination. I can build a form out of MDF, but have no idea whether trying to bend cypress is a good or bad idea--strikes me that cypress trees can be pretty bendy, but don't know if that translates into good bending material for lamination. Anyone care to weigh in on whether I should forge ahead? What about ply thickness?

[Tony Bilello]

So, I started thinking this might be a good excuse to try bent lamination. I can build a form out of MDF, but have no idea whether trying to bend cypress is a good or bad idea--strikes me that cypress trees can be pretty bendy, but don't know if that translates into good bending material for lamination. Anyone care to weigh in on whether I should forge ahead? What about ply thickness?
I have worked with Cypress before. I have bent it by pure pulling force to replace boat planks. but, I have never tryrd laminating it.
It bends relatively easy, so that part should go well. Now here is why I would suspect it would be a really good idea. When ever you glue up two pieces, they work in tension to eachother,. This should make the lamination much stiffer than if you just bent a thick board. And yes, if you just cut a curve in a single board for the rockers, they will have several weak areas.

IMHO

Tony B

[jim mckee]

Why bend wood?

Make a traditional style Adirondack and add a rocker foot to each side.
My design has a footstool that can be stowed under the char so that would have to be left out of the design.

[Eric DeSilva]

Why bend wood?

Well, if you simply cut a curve out of a piece of flat wood, you end up--at some point in the curve, where you have straight grain running across (or nearly across) the width--that seems weak to me. Especially as this happens towards the front and back of the rocker. Front isn't too much of an issue, but the back... If someone is rocking far back, all the weight of the chair and the occupant are on the weak part of the wood. The two choices are either using something with a lot of width, which strikes me as aesthetically unpleasing, or doing a bent lamination so the grain runs with the curve.

[D-Alan Grogg]

I made a hammock stand in 2004 using bent lamination of Cypress. It turned out very well I think. Plenty strong, but still flexes nicely to give a good feel when in the hammock. I used 1/8" thick plys, but this curvature was fairly large. For tight curves, you'll need thin plys. You'll have to experiment a bit. Hopefully, I can attach an image.

[jim mckee]

My Rocking Adirondack

[Dennis Peacock]

I've done bent lamination with Cypress. So far? They've held up for about 3 years. They see near daily use for about 8 months out of each year and sit on the front porch every day of every year. My bent-lams are not the rocker part of the chair, but the upper back support for the curved backs of my adirondack chairs. The rocker part of the chairs need to be made from something like White Oak so it will hold up to long term use. I'd be afraid that the Cypress would be too soft over time to hold up to regular use.

[Lon Schleining]

Eric, if you first build a male mold to the inside radius you want, you can mill the wood to the right thickness for bending by trying different thicknesses. Once you can hold a single piece on the mold with just a couple of fingers, it's the right thickness.

If you chop this sample piece into short segments, you can stack them up until you get the over all height you want.

That said, please please be sure this cypress is dry enough to glue. (See Bruce Hoadley's book Understanding Wood.)

I would use either epoxy or plastic resin (UF) glue NOT any of the single part glues like Tightbond or polyurethane. When I do this, I glue all of the layers at once.

[Adam Cavaliere]

I built Norm's plant stand which called for cypress. Some of the pieces required a bent lamination of cypress. I cut them down to 1/8 inch and glued them up. The only problem was I couldn't bring myself to throw away the jigs I used for gluing up. So now the sit in my attic, probably until I move and thow them out! :rolleyes:

It seems others have done the same and have had success too.

Obviously we want to see pictures when this is built! :D