Anybody have any advice? I spent over an hour steaming the damn stuff,
and it was cool again before I could get it into my jig, and it
cracked as soon as I tried to bend it.
Various web searches indicate that you shouldn't try to bend
kiln-dried wood or wood that's old enough to have a moisture
content below 10%.
Has anybody else had any success here, or should I be checking
to see if there are any lumber yards with green redwood they can
Kiln dried woods don't bend well, the kiln collapses the cells and they lose
elasticity forever. Worse, redwood isn't particulary good for bending so depending
on how tight a radius you need, it may not work at all unless very green. Best bet
is probably a combination of kerfing and steaming.
On Saturday, September 14, 2013 9:10:06 PM UTC-5, Edward A. Falk wrote:
Steam, for a longer time, thinner flitches/panels (more quantity than you n
eed), bend to form/radius (plus a little more), allow to dry, then laminate
. The wider the panels, the more difficult it will be. Some may break, s
plit, hence the more quantity. As for the laminations, layer the flitches/
panels opposite ends, as per in line as they were cut from the original boa
rd, i.e., don't match the original faces.... does that make sense.
I bent walnut strips this way some years ago. After several failures of ot
her techniques, I first soaked the laminates in hot water (I kept adding ho
t water to the bath tub, as the water cooled) and I added glycerin to the w
ater, to soften the laminates.
....Glycerin is also used to soften cane, for caning chairs.... makes the c
ane more soft and supple, to weave, as opposed to soaking the cane in hot w
ater, alone. Glycerin is the stuff added to soapy water that makes for the
soluton for (kids) blowing bubbles.... you know the blowing bubbles "toy"?
After the hot water/glycerin soaking (for at least an hour), then I steamed
The arch on the top-back of this maple chair (left) was similarly soaked, s
teamed and laminate bent:
If I recall correctly, I cut 15 laminates and many broke or split during th
e process. I needed eight 1/8" thick laminates (1-1/4" wide) for the form.
That arc is certainly not a tight radius, either. The grain of the maple
wasn't very straight, either, lots of unevenness (somewhat figured), so th
at made for more difficult bending (without breaking/splitting around/along
the figures). Your redwood may likely have straighter grain.
I haven't bent redwood, but have made several laminated bends with kiln
The first time was for trim for our arched living room window. I didn't
have a bandsaw at the time and the boards were about 7" wide, so my only
solution was to run them through the planer until they were 1/4" thick.
Then I slowly and carefully bent the boards to fit inside the window frame.
I heard a few cracking sounds that alarmed me, but the boards never broke.
Since then I have used my bandsaw to resaw 2" wide cedar boards to 1/4"
thickness. Then I used exterior glue and a form to build laminated wood
arches for a garden cover. The biggest problem here is getting everything
clamped together before the glue sets up. And LOTS of clamps. :)
Are you talking about the board across the front or the roof skin itself?
If the former, forget it, you aren't going to get that bent. Laminated or
sawn or kerfed, sure; bent, no way.
If the latter and you are going crosswise with the boards there should be no
need to bend them beforehand; they should bend just fine as you fasten them
down to whatever they fasten to. assuming that the supports define the
shape. It could be a bear securing them to each other though. Of
course,the simplest thing would be to lay them on length wise, easy to use T
& G for that.
Either way, it isn't going to keep out rain water. You would get lots of
info/ideas from books on boat building.
Your choice, of course, but in the Sketchup the boards in that area look
like they are a bit higher than those in the roof proper. I don't think it
would look odd at all for them to go crosswise rather than lengthwise and it
would be just worlds easier to do.
I agree with you. IIRC, Mr. Falk laminated a bunch of 1/16" strips; I think
springback from that thickness would be non-existent.
Over the years, I have laminated several things; most recently four 1/4" x
5" x 72" strips to make a 1" thick arch top jamb for arches (I made two
jambs) I was making screen doors for. My bending jig was very simple...a
piece of 3/8" ply with pieces of 2x4 glued to it every 8" or so. I bent one
piece into the jig, held it with a clamp in the center then applied glue to
the second piece and - starting from one side - bent it onto the first; when
I had bent as far as I could go, I removed the one clamp holding the first
and continued clamping both. I then repeated all of that with the remaining
After drying, zero spring back. I don't recall ever having any on anything.
I don't recall the thickest pieces I have laminated to a curve, probably
1/4". However, I have dry bent numerous boards...when I had a sailboat I'd
occasionally need to replace a plank; those were 1 1/4 thick douglas fir on
the order of 5-6" x 10-16'. The longer the better for those :) And once
theyhave been on for a while, they take a "set" close to the curve to which
they were bent.
In general, I think people worry too much about stuff. And not only
woodworking...stuff like lead, asbestos, mold...all sorts of things. I'm
not suggesting people shouldn't exercise caution, merely that things like
some mold on a basement wall isn't the kiss of death for all inhabitants.
Relative to woodworking, if I have something I need to do that I haven't
done before I try to figure out various ways of accomplishing it, try what
seems easiest and has a reasonable chance of success and do it; if it
doesn't work, try another. generally, I hit it the first try, I HATE
re-doing anything :)
I use epoxy for laminations for the following reasons:
1* I had lots of it.
2* When using a slow hardener at 25C(77F), you have about a 25 minute
life which can make all the difference how you do the job.
Gorilla glue is NOT epoxy, it's just another way to say GARBAGE.
I've used a lot of System3.
A gallon of resin and a couple of different speed hardeners and you
are good to go.
BTW, I still use a lot of Titebond II, just not for laminations or
where gap filling is req'd.
Gorrila glue isn't epoxy. If you want/need epoxy, this is a good source...
One of the nice things about epoxy is that it can be thickened; that is nice
because it will fill voids. Another nice thing about it is that it needs
minimal clamping...just enough to keep things where they should be. That
latter nicety would have been of little value for your bending operation but
it can be very handy in other situations.
Other good choices wold be resorcinol or plastic resin glue. I used to use
the latter a lot when I had a boat, worked well but always seemed wierd to
me; I mean, mix the tan powder with water and the stuff wasn't even sticky
On Tue, 03 Dec 2013 13:31:01 -0500, Mike Marlow wrote:
Certainly creep is not a problem in most joints because they're not under
constant pressure. But bent laminations are. Titebond says the following
"Because PVA glues tend to “creep”, or slowly stretch under long-term
loads,they are not recommended for structural applications."
They make the stuff - I'll go by what they say.
This message was for rec.woodworking - if it appears in homeownershub
they ripped it off.
They look pretty good to me for a first attempt.
Now that you know the pitfalls, I bet you can't wait for an excuse to
make some more.
By the way, your process is pretty much what the major furniture
industries do to make theirs, minus the giant hydraulic presses and
microwave resin curing, of course. :-)
"Playing is not something I do at night, it's my function in life"
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