Curved or Bending Materials

[Steve Crawford]

I've seen examples of very thin ply cut in such a way that it can be bent over for use as the spine/hinge of a book for example. This seems to be done by a large number of parallel but offset cuts (if that makes sense?), done in such close proximity to enable the material to flex without breaking.

I'm wondering if there are any members that do this regularly, and if so what thickness materials do they think can be used. Could I do it with 3mm or even 6mm MDF for example or even clear acrylic? I want to create corners to curve through 90 degrees at most.

[Mike Null]

Steve

There were a number of examples of boxes as I recall with most being 3mm. A couple of searches should turn them up.

[Guy Hilliard]

What you are looking for is "laser cut live hinge". I have cut them in 6mm Baltic Birch plywood. I cannot think of a reason they would not work in 6mm acrylic, I've never had an order for that so I haven't tried it yet. A Google search will find tons of examples and how to's.

[Chuck Stone]

It seems to work best in plywood because of the alternating grain direction of
the different plys. I've tried it in acrylic but it snapped.
Come to think of it, every project I used it on has snapped after a while.
Seems to be one of those things that works well as long as you don't use
it a lot. Or I could be using the wrong materials

[David Somers]

Chuck,

I have a feeling your experience with this is right. Those wood fibers will fatigue with use and age and break, sort of like how metal will break if bent repeatedly.

I wondered if keeping the joint well oiled might help some with longevity? Keep the fibers somewhat supple? It is a cool and novel idea though and worth using so long as you don't expect to pass it on to your great grandchildren as a functional joint.

I am stuck on hold right now and happened to be pondering this idea. If it did turn out you could keep this kind of joint supple by oiling it periodically my guess is almost no one would do it. I happened to be looking at some items in a museum collection that had leather hinges. They were pretty darned old, and were still functional because the owners had treated the leather over the years, maintaining it carefully. And now 150 plus years later we have that item intact and functional because of that maintenance by the users. We don't seem to be interested in doing that nearly as much these days. There are all kinds of reasons for this of course. But it is a shame regardless. Lots of finely crafted items in people's hands that won't stand the test of time because they aren't given minimal care. A few will care for items. But very few in my experience.

OK....enough pondering. Just got off hold! Cheers everyone!

Dave