Bending wood... any wood?

[ecks79]

Hi gang!

Something i've been reading up on and watching a lot of video's on is bending wood... most of the material i have found is on steaming/bending as apposed to thin cut/bending.

my questions are:

(1) Is cutting strips and bending wood (apart from time) just as good as steaming? - i don't have a steamer and figure ripping and glueing was far easier
(2) Can i use this method for just about any timber type?
(3) How thin do i have to go if i rip timber, without going to thin... or does this differ per wood?
(4) All the bending in my project would of hardwood, are there any particular hardwood that is better?
(5) Is there any other key things one should know?

also, any additional material you might have or even done yourselves would be greatly appreciated... one can never have too much reading material!

thanks again guys!

Tony

 

[woodguy7]

Tony

I have done loads of bent lamination curves but never done any steam bending.  Like you said, the thickness of the lamination's depend on the type of timber & also the radius.  When making your formers allow for some spring back as the piece will always try to straighten a little.  Clamps, you need loads & can never have enough.  I find approx 3 to 4 mm is the thinnest you can practically go with the lamination's.  I find oak a pain to bend sharply as it does not dress thin very easily & usually end up with a lot of waste.

Good luck, Woodguy.

 

[jonny round boy]

Steam bending is really quite easy, and cheap to do. You could probably build a steamer for about $100. Once you have the steamer, it's a lot quicker to do than cutting, smooting and then glueing thin strips.

All you need to build a basic steamer (assuming you're bending small sections) is a length of drainpipe with removeable plugs at both ends, and a cheap wallpaper steamer. I haven't looked, but I'm sure there must be thousands of pages online showing how to build one.

some of the easiest timbers to steambend are beech and ash.

 

[mattfc]

I would also look at vacuum forming, it works great, plus you only need one half of the mould, the vacuum bag does the rest. See this site for more details
http://www.joewoodworker.com/veneering/vacuumforming.htm

 

[jonny round boy]

I've just had a very quick look, and this page shows how to make the basic steaming box I was talking about. Very simple.

One alteration though - the author recommends using bolts for the timber support, and covering them with plastic. It'd be much easier to just use small section rigid plastic pipe instead of bolts.

Also, don't pay too much attention to the bit at the bottom about making a former out of bendy MDF, though - it seems a bit flimsy to me!

 

[jvsteenb]

All forms of bending introduce a form of pre-stressing the material that heightens the stifnness and enhances some strength properties of the wood in the plane of the bend.

That said, the laminated bend introduces much more "pre-stressing" in the material then steambending does. So if you're looking for a seriously stiffer piece, lamination bending would be your best bet.
In some cases it's also easier to do, and more predictable.

Then again, while steambending you can bend in more planes, and the look will likely be more natural.

In both cases, it's not the bending but rather the fixating while drying/cooling  that's the hard part.

Both have their advantages. Mind you: not all woods lend themselves well to either method of bending.

Regards,

Job

 

[Jesse Cloud]

I've done steam bending, vacuum forming, and bent laminations.  They have pros and cons.  Here are some thoughts:

Bent lamination is my favorite method.  It does take a lot of time (and a lot of clamps, see below), but the results are very predictable and complex, tight curves can be bent.  The answer to your question of how thick the lams should be will probably sound facetious, but you simply make the thickest lam you can bend into the shape of the form.  The thickness will be determined by the radius of the curves (tight curves are hard to bend), the type of wood, and the strength of the user.  I typically use maple, walnut, or ash for my work.  With practice, the glue lines between lams are not noticeable.  You will need lots of clamps, a bandsaw with a sharp blade, a thicknesser and lots of glue!
[attachimg=#1]

Steam bending is a good option if the presence of glue lines is unacceptable.  Air dried wood bends much better than kiln dried.  The amount of time in the steam depends on species of wood and thickness.  If you are bending thick wood or using tight curves, you will need a helper or two and some heavy duty clamps!  Probably due to my lack of experience in this method, I have had a few failures, but eventual successes.  Lots of plans for steam boxes around.  They can be built with readily available parts.

Vacuum forming is fast and predictable.  Hardest part is keeping the assembly together while fitting it in the bag.  The pump and the bag are not cheap, though.  Its pretty much the same as bent lams, but the vacuum pump does the clamping.

Hope this helps.  Feel free to send me a pm or an email if you have questions.

Jess

 

[mouppe]

Here is a ship's hull that I built using walnut strips. Whilst it is only four feet long and the walnut strips were thin, the principles are the same. At the bow the wood was bent significantly. I soaked the strips in a wallpaper tray and then used a soldering iron to curl them. I would roll the soldering iron back and forth taking care not to scorch the wood. When the wood was dry, the strips went back in the tray for more soaking. Using this method you can curl a piece of wood as tightly as you like. Some people peg the strip out to a template whilst drying but I never found it that useful. With thicker wood, I would use the bath as a larger tray.

I reckon I cracked about 5% of my strips so get a little extra wood for spares.

Richard.

[attachimg=#]

 

[greg mann]

Some good advice here but I might add that quarter sawn wood bends better, with more strength, and more predictability than flatsawn.

 

[Alaska Ranger]

Do not forget kerf bending, wherein you cut an evenly-spaced series wedges, obviously with the fat end of the wedge on the outside of your curve.  Normally this is done when only the innermost portion of the curved wood remains showing at the project's end, but you also can infill the wedge kerf with a contrasting wood for a dramatic final result.

 

[jonny round boy]

As an aside, when I was at college doing a furniture-making course, we did some work on bending timber. As part of that, we watched an old video taken in a big industrial factory. I can't remember what they were making, but they had a jig set up for mass-production, and were steam-bending 90 degree bends into what looked like 6"x6" timbers, to a radius of less than a foot! [eek]

 

[ecks79]

As always, loads of helpful answers there. Thanks everyone, greatly appreciated!... im going to give the laminate strips a go this weekend and see how i fare first, then i might try building a steam bender... thanks for those links!

Since i don't have a bandsaw, a table saw would do i assume? it's just with a bandsaw i have less waste? and if my timber is already finished, would i need a thicknesser?

thanking you all again!
Tony

 

[DavidCBaker]

I don't know if you have it or not, but a Festool plunge saw (either one)--along with the parallel guides--is an awesome way to make the laminate strips and get them exactly the same thickness.

 

[Deansocial]

As an aside, when I was at college doing a furniture-making course, we did some work on bending timber. As part of that, we watched an old video taken in a big industrial factory. I can't remember what they were making, but they had a jig set up for mass-production, and were steam-bending 90 degree bends into what looked like 6"x6" timbers, to a radius of less than a foot! [eek]

would that be done with compressed hardwood?

 

[ecks79]

Thanks David, i only just got one of those! turned up last weekend ill give that a go. is that better than mounting it in the table?

 

[DavidCBaker]

Thanks David, i only just got one of those! turned up last weekend ill give that a go. is that better than mounting it in the table?

Yes--I think it would be a lot easier.

 

[ecks79]

Richard, thats a nice hull... how long did that take you? impressive!

When you say you soaked, then used a soldering iron, how big was the soldering iron? that must have taken a while? and how did you keep the shape of the wood whilst it dried.

Im just wondering how the timber needs to get before it will bend... would an iron work in the same way? - stupid idea?

 

[mouppe]

Richard, thats a nice hull... how long did that take you? impressive!

When you say you soaked, then used a soldering iron, how big was the soldering iron? that must have taken a while? and how did you keep the shape of the wood whilst it dried.

Im just wondering how the timber needs to get before it will bend... would an iron work in the same way? - stupid idea?

The hull only took a couple of days. You would be surprised once you get going how quickly you can do it. It actually takes longer to cut the planks to the right taper and length.

It was a regular soldering iron. You can get attachments that look like 1" metal cylinders to go on the end of the iron but I found it easier to clamp the soldering iron in a vise and just bend the plank around it. The plank will keep about 70% of the bend whilst drying, then you soak it and bend it again until you get the desired shape. Some people peg the plank out whilst it is drying but this never worked well for me.

Whatever you are heating the wood with needs to have a curved surface, so I don't think an iron would work.

 

[Chowman]

Earlier this season Norm Abrams made a bent wood coat rack on New Yankee Workshop. I copied his answer to an inquiry from a fan on the NYW site:

"Mike Dunbar who runs a chair making enterprise in New Hampshire called the Windsor Institute.Com taught us how to make his steamer from parts available at a home center. Check it out. Good Luck" (attributed to Norm Abrams)....here's the website for Windsor...http://www.thewindsorinstitute.com/

Essentially, this pvc drain pipe technique was described already by jonny round boy. THe only thing I would add is that Norm used a NEW gas can as the boiler with a piece of tubing leading to a nipple on the pipe. He heated it on a outdoor propane burner ring used for a turkey fryer or here in Maryland, we would use that device for steaming crabs!

The key to success is having your jigs ready to go...very limited time to get wood bent before it begins to cool and lose it's pliability.

In the shop at work where the guys fabricate exhibit structures, we make use of a plywood product called bending luan, also referred to as wacky wood. This is good for projects where you are going to use laminate or a veneer surface as the final show surface. Wacky wood does not have a fine surface like a birch veneer plywood. It comes in two configurations: column and drum where the flexibility runs in one direction or the other. We are in the midst of fabricating a centerpiece in the shape of a ying-yang. Tops are 3/4" birch ply, fronts are wacky with laminate.

Hope this is helpful to someone.

Ralph

 

[Jesse Cloud]

As always, loads of helpful answers there. Thanks everyone, greatly appreciated!... im going to give the laminate strips a go this weekend and see how i fare first, then i might try building a steam bender... thanks for those links!

Since i don't have a bandsaw, a table saw would do i assume? it's just with a bandsaw i have less waste? and if my timber is already finished, would i need a thicknesser?

thanking you all again!
Tony

Hey Tony,
Yes, the bandsaw will give a much better yield than a tablesaw.  Its important that the lams should be smooth and bottom side parallel to the top (or the result will be lopsided).  If you must use a tablesaw or a festool plunge saw, you will need to make the lams smooth and parallel.  A planer/thicknesser gives the best results.

If you would like to share with us what your project is, we might be able to offer better advice. 

Jess