LumberJocks

Help with basic bent lamination

  • Advertise with us

« back to Woodworking Skill Share forum

Forum topic by jamsomito posted 12-21-2017 03:07 PM 927 views 1 time favorited 21 replies Add to Favorites Watch
View jamsomito's profile

jamsomito

311 posts in 629 days


12-21-2017 03:07 PM

I’m trying to make this simple razor holder posted by Steve Ramsey. https://woodworking.formeremortals.net/2014/11/shave-in-style-make-this-classy-razor-stand/

My first attempt worked but I don’t think it has enough of a curve, it was twisted slightly, and there were a lot of voids. My next one I ripped down in width a bit so I could more evenly apply clamping pressure to address the voids, but I tried bending it further and it snapped. I was thinking of spritzing them with water or heating them a bit in the oven… Any other thoughts? Would a full clamping form out of plywood help or would they still snap?

Thanks for any tips.


21 replies so far

View joey502's profile

joey502

544 posts in 1721 days


#1 posted 12-21-2017 07:10 PM

I would use a form made from mdf for the glue up. Make the first layer and then glue and flush trim each layer after until you have a form wife enough to make your piece.

The curve you are going for is not too sharp, it will be fine with a form to wrap around.

Use a 1/2” layer of plywood as a caul when you clamp your lamination to the mdf form. That will get you a little more even clamping pressure.

View Rich's profile

Rich

3888 posts in 793 days


#2 posted 12-21-2017 07:20 PM

^^^^^ +1. I might add that lining the face of the form with cork will help eliminate voids, and topping that off with clear packing tape will prevent glue from sticking to it. There’s nothing worse than your workpiece getting glued to your form.

-- Half of what we read or hear about finishing is right. We just don’t know which half! — Bob Flexner

View Loren's profile

Loren

10477 posts in 3851 days


#3 posted 12-21-2017 07:24 PM

Personally I would saw the laminates to about
2mm and bend them on a steel pipe heated
with a propane torch. I spritz the wood with
water on the inside of the bend to keep it moist.
If the wood is soaked excessively the grain can
blow out on the outside of the bend as the
soaking weaken lignin bonds. I believe most
luthiers use spritzing rather than soaking these
days but both approaches can work.

Once bent I would see about making a 2-part
caul to clamp up the laminate.

View jamsomito's profile

jamsomito

311 posts in 629 days


#4 posted 12-21-2017 07:26 PM

Thanks everyone. I will try the form.

These were resawn to 1/16 inch. I have some that got a little thinner unintentionally so I’ll try those too.

View Aj2's profile

Aj2

1881 posts in 2001 days


#5 posted 12-21-2017 09:27 PM

I second the use of a form. You don’t mention what wood you are using and that will make a difference some woods don’t not like to be bent. Some woods do well with bending but need to be Resawn the right thickness to match the curve. Then there’re the glue factor.
There’re a lot to curved laminations so don’t beat yourself up if you don’t get it right from the get go.

-- Aj

View jamsomito's profile

jamsomito

311 posts in 629 days


#6 posted 12-21-2017 09:40 PM

It’s zebrawood.

Made a quick form out of scraps and trying that now. Didn’t snap. A lot of that was attributed to the thinner pieces, but it is a lot more uniform now for sure too.

View jbay's profile (online now)

jbay

2893 posts in 1103 days


#7 posted 12-21-2017 09:44 PM

Your probably going to get a little spring back.
I usually make the curve a little tighter to allow for a little spring back.
also titebond is going to let it creep and spring back more than if you used a urea glue.

View John Smith's profile

John Smith

1488 posts in 366 days


#8 posted 12-21-2017 10:24 PM

the more layers of veneer you use, the more ridgid it will be.
two-part epoxy would guarantee it will retain its shape for many years.
in laminating veneer pieces, I would not use the expanding urethane glue.
want to make it Superman Tough ?? put a piece of fiberglass cloth between a couple of layers with epoxy.

-- I started out with nothing in life ~ and still have most of it left.

View DS's profile

DS

3033 posts in 2624 days


#9 posted 12-21-2017 11:04 PM

Luthiers use some sort of bending iron like Loren suggested. I have an electric model myself.
(Less chance of fire in a room full of sawdust – IMHO)

Heat softens the lignon in the wood and facilitates easier bending. When the lignon cools, it will hold the new shape without coersion.
Moisture ensures the temps don’t go above 212 degrees and start burning your piece, plus, the moisture will carry more heat into the center of your piece.

The form idea is good, but, without enough heat, even that can and will crack some wood. (And you have the added joys of trying to predict spring-back in your piece)

Hope any of this helps you. Bending can be both challenging and fun.

Best of luck to you.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View runswithscissors's profile

runswithscissors

2894 posts in 2228 days


#10 posted 12-22-2017 07:59 AM

You could easily bend those laminates with a heat gun. Overbend a little, as there will be some spring back. Glue them up on a form, and the result will be rigid and strong. For extreme bends, a bending strap (thin steel, like the banding used for slings of lumber), is really necessary.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View jamsomito's profile

jamsomito

311 posts in 629 days


#11 posted 12-23-2017 05:43 PM

Just following up here. I did one glue up with my remaining zebrawood and it turned out ok but I think my plys were a little too thin. Too much glue, not enough clamping pressure and it was just a little brittle and didn’t turn out the greatest. But it worked.

I went back to my first one that didn’t have enough bend and improvised a new base with some scraps from the inside of a drawer on a bandsaw box I was making at the same time. With my oscillating tool I cut a mortise at about a 45 degree angle and it turned out ok.

Here’s both.

I had a friend staying with me who has never worked with wood before and I thought this would be a good project for him since I already had the form. We tried resawing some maple strips from some other scraps I had laying around and it turned out awesome. Best of the bunch by far. Great glue up, no cracking, no voids, nice and clean. I’m glad for his sake on his first project that it was a win.

Thanks for all the advice! I will be doing more bent lamination on other projects in the future.

View DS's profile

DS

3033 posts in 2624 days


#12 posted 01-02-2018 10:11 PM

I bent the moldings on this bar using my electric bending iron.

The moldings were made straight and I ripped them into 1/4” to 5/16” thick strips before bending and re-laminating. (Using two straight moldings to yield 1 bent molding)

A thin board like yours could be done in one piece with no lamination.

-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View runswithscissors's profile

runswithscissors

2894 posts in 2228 days


#13 posted 01-03-2018 09:18 PM

Just playing around with ideas for shelf brackets, I made this. Bent with a heat gun, no moisture, no laminating. Wood is well seasoned white oak. Bent part about 5/16” thick. Bending took about 5 minutes or so.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

View DS's profile

DS

3033 posts in 2624 days


#14 posted 01-03-2018 09:36 PM

I love the clean lines of this bracket!

Can I steal this design? ER, I mean, USE this design?


Just playing around with ideas for shelf brackets, I made this. Bent with a heat gun, no moisture, no laminating. Wood is well seasoned white oak. Bent part about 5/16” thick. Bending took about 5 minutes or so.

- runswithscissors


-- "Hard work is not defined by the difficulty of the task as much as a person's desire to perform it.", DS251

View runswithscissors's profile

runswithscissors

2894 posts in 2228 days


#15 posted 01-04-2018 12:12 AM

The bent part is let in to the straight parts by making a groove. The width of the bent part is 7/8”, so probably a couple of passes over the dado, unless you have a really thick (wide?) dado stack. Of course you could make them narrower or wider. The grooves end where the bend exits from the straights. Not hard to do with a dado. Doesn’t matter whether the curved end of the dado exactly matches the curve in the bent part. The curve should appear to grow right out of the straight legs.

Actually, I made those grooves with a router bit in a shaper. But way too scary! I wouldn’t do it that way again.

For hanging, you can use the little blind steel inset hangers that take the head of a screw. Sort of a keyhole slot in those hangers. Don’t have a photo, but they’re widely available.

When I’m bending a piece like this I always use a steel bending strap, well clamped at both ends.

-- I admit to being an adrenaline junky; fortunately, I'm very easily frightened

showing 1 through 15 of 21 replies

Have your say...

You must be signed in to reply.

DISCLAIMER: Any posts on LJ are posted by individuals acting in their own right and do not necessarily reflect the views of LJ. LJ will not be held liable for the actions of any user.

Latest Projects | Latest Blog Entries | Latest Forum Topics

HomeRefurbers.com