Bend Wood 3 Ways

I am on a mission to build the most comfortable chair, ever.

TANGENT! -Do you play video games? I don't, but have recently learned some vocabulary that has a lot of bearing to this mission I am on of building the most comfortable chair ever- the side quest.

A side quest (apparently) is an objective given or chosen by the player that has no direct bearing on the main story/campaign/objective of the game.

Well it turns out to build the most comfortable chair, WAIT- most attractive chair, (do I want to build a comfortable chair or attractive chair? Can't I have both?) ANYWAY... we have to go on a lot of side quests.

We could talk- I could talk - for a long time about chair comfort and design. Most of this is subjective anyway because I have not actually SAT in many of the chairs I am interested in. This is why I need to build them so I can test them and make an objective observation. Come see me in 10 years...

What I'm getting at, is that on my journey to build the most comfortable chair ever, I have learned how to bend and curve wood because surprise, surprise...chairs are more comfortable (debated by some...I'm looking at you, Chris...) when they follow the curves of the human form. I don't have a lot of curves, but many do...I digress...

Let's talk about 3 ways to bend/curve wood- shall we? We are going to cut it, laminate it, and steam it.

Wood. Most any wood is suited for the first 2 methods. Ring porous, straight grained hardwood is the best for the last (steam bending.)

Tools to cut wood (handsaw, jigsaw, table saw, bandsaw)

Glue, bending forms, and clamps.

Drain/waste schedule 40 PVC pipe and end caps, Radiator hose, tea kettle, hose clamps, garden hose fitting, stainless steel strap, stainless steel all thread, food temperature probe.

I can feel everyone collectively rolling their eyes and skipping down to the nitty gritty- that's fine, it's fine...

The way I get my kids to sleep at night is to tell them shop stories full of wood grain, movement, Rockwell hardness, etc... 56 seconds in and they are all sound asleep.

That being said, if things don't work out like you had hoped...chances are good wood grain is a major factor. I have said before that wood grain is like drinking straws that are held together with glue, you can also picture a broom dipped in glue and allowed to dry- that is essentially how wood behaves when you are trying to cut, shave, sand, bend, etc...

When you look at a tree trunk that has been cut down, you see the growth rings, everyone is familiar with that image. I even drew one for you...you are welcome. It's the benefit of having a workbench that is also a light table/whiteboard. When you see a cathedral pattern in wood, it was cut somewhat diagonally from those growth rings. When you cut a huge curve in wood, you create short grain, where it can easily snap...that is fine for a decorative wall-hanging, but not so much for a rocking chair. This is where bent lamination and steam bending are really useful.

For some chairs, you want to split the wood with a froe so you follow the fibers of the grain, this way you know it runs the entire length of the piece, and is much stronger. If you cut it, you ignore the grain and create sections where the grain runs out creating weak spots. These can break- maybe not when you first build the chair, but after a few months/years of use it can snap. No one wants that...

If you are careful about how you orient your grain, and what type of joint you use to join the pieces- you will be much more successful. So let's talk about how we can make straight things curvy.

Some curves and bends can simply be cut straight out of the wood. As long as it doesn't compromise the structure of your project, this is the simplest method. If the curve is structural or really steep, you run the risk of it breaking, and wasting a lot of wood by just cutting the shape.

When I built this tiny chair for my little buddy, I had a problem...the rules for the contest said you can only use a single 2 X 4. That's not a lot of material to work with, and it's not curved. (well...some of them are!) I wanted the backrest for the chair to be curved in 2 dimensions, that would make it more comfortable and look nicer.

The way I achieved this was to leverage the fact that wood can be glued together invisibly if your glue surface is jointed smooth. This is a trick I saw Sam Maloof use on his rocking chair head rest and dining chair arms: saw the wood in a curved shape from one side, and glue it to the other.

For this back rest, it meant cutting the curve from the front side and gluing it onto the back side. This made the curve perfectly parallel and conforms to the arch in your back. I also wanted it to curve up (like a smiley face) or down (frowny face) for design purposes. I went with the frowny face shape and cut that (after the first cut was done and glued) by cutting a curve from the bottom and gluing it on the top.

Another method that is popular is to cut several pieces nested against each other, then stacking them on top of each other and gluing them. You don't waste too much material here because you are nesting the pieces when you cut, then creating greater size and volume by stacking them.

The last way I will mention is to cut a bevel on the ends of boards and gluing them together. This is called "Coopering." and it is how wooden barrels are made. I used this technique to create the head rest for a chair I am working on. I used a piece of butcher block that I already had, and cut the angles in the pieces to get the curve I needed. I then used a router jig to smooth out the facets so it was curved and parallel.

Long ago, I thought this was THE BEST thing ever. I used this technique to make the click-bait, beautiful rocking chair you see here. (Never mind that it ended up NOT being comfortable to sit in) I knew that the wood I had was not strong enough to cut the curves straight from the board, and I couldn't get my hands on anything worth steam bending, so it seemed like this was the only way. I have come to learn that laminating takes A LOT of time, sawdust, and GLUE. I would almost rather start with steam bending now that I have done several bent laminations. You will buy a fresh bandsaw blade or two, a table saw blade, and a gallon of glue. With that money, you could just buy a board that will steam bend nicely. With that said, laminating is a great solution for some projects.

If you want to get into the nitty gritty, I review these in depth in my past inctructables- "Better Bent Lamination Forms" and "Bent Lamination Shortcut." To successfully achieve bent lamination, you want to cut your laminates to about 1/8" thick. It can be a little thicker if your bend is not severe. If it is a severe bend you will want to go a little thinner. Each laminate needs to be planed smooth, so they glue up nicely. You should always end with an odd number of laminates, so if you have 6 laminates, use 5 or 7 instead- it will be more stable.

Make sure you have done a dry run before you start gluing so you are sure you have enough clamps (you probably don't- borrow some). I literally used my winnings from the first bent lamination instructable to buy enough clamps to do the next one... The stress level of this glue up increases exponentially when they start sliding around-so make sure you have built a great form and have enough clamps.

This has to be the most intimidating technique when it comes to bending wood, but is the most satisfying when you finally get it right! I started with the first set up you see, and realized that the hose I had between the steam kettle and PVC pipe was not strong enough- the steam kept escaping by the spout. I went to an automotive store and got a radiator hose, and that solved the problem.

When you steam bend wood, the rule of thumb is to steam it for 1 hour for every inch of thickness, and the temperature needs to be 200 degrees Fahrenheit or above.

I modeled my steam bending setup after Mike Dunbar's. He is a great resource for Windsor chair making. I have a Schedule 40 Drain/Waste pipe, with a garden hose fitting screwed into the side, that is what the radiator hose attaches to with hose clamps. I have all-thread running through in 2 places to keep the wood off the bottom of the pipe. If you let the wood lay at the bottom of the pipe it will not come up to temperature because that is where all the water from the steam ends up. One steam pot/kettle of water will get you a little more than 1 hour of use, and it comes up to temperature pretty quick. If you need to steam longer, have some more hot water ready to add to the kettle.

It's important to have everything ready to go ahead of time, before you start steaming. You need a bending form, clamps, and (I highly recommend) a metal strap. My first test failed because I didn't have a good strap, my wood was too dry, and it probably wasn't the right kind of wood for steam bending. I think I could have had success if I followed my second attempt recipe!

My second attempt was successful: I made sure the wood was straight grained end to end, soaked it in the bathtub the night before, and used a metal strap with my form clamped securely to the work bench. Soaking the piece ahead of time gets water into the wood pores, that conducts the heat from the steam very well to ensure it is heated all the way through. I steamed my piece for 1 hour, even though it was a tiny 3/4" octagon, I didn't want to take any chances. The metal strap keeps the wood in compression so it bends much better than without a strap, where you could have a tension failure.

Interestingly enough, there is this video by Matthias Wandel where he just uses his kitchen oven to bend parts for a kitchen chair. He obviously had enough heat, and the parts were small enough to fit in his oven, so it worked! I have even heard of people using a microwave for tiny items, though I have never tested that.

There we go! 3 great ways to achieve bends, curves and arcs in your furniture.

Here are the basic pro's and con's for each method:

1. Sawing is the easiest way, with the least amount of set up. The downside is it can waste a lot of material, and be rather weak if the grain doesn't follow the curve.
2. Bent lamination is really strong and stable, and you can use any type of wood. The downside is you need a lot of glue, powerful clamps, and a way to cut your laminates.
3. Steam bending has perfect grain throughout the entire piece, so you can cut and sand it without exposing glue lines like bent lamination. The downside is it has a steep learning curve, there could be some spring-back (piece relaxes/straightens a bit after bending), not all woods are prone to steam bending and can crack

So here we are, after many side quests...I think we have learned some valuable lessons and have an arsenal of tools to make the MOST COMFORTABLE CHAIR IN THE WORLD.

I will keep you posted on that...