By David J. Marks
It has been said by many furniture makers that chairs are one of the most challenging pieces of furniture to build. The reason for this is that in order for a chair to be successful it has to be strong enough to support the weight of an individual while being comfortable enough to sit in for lengths of time as well as looking ascetically pleasing from a 360 degree perspective.
When I design a chair, I begin by doing lots of sketches. Once I have some ideas that I like, I will choose one and draw a full scale front, side and plan view onto a piece of eighth inch plywood or MDF (medium density fiberboard). From the full scale drawing I can generate a mockup. The mockup can be assembled with screws or hot melt glue and made from mdf and scrap wood. Basically the mockup is something to give you a rough idea of the overall dimensions and proportions of the piece. Once you have a mockup that you like, you can build a prototype.
The prototype differs from the mockup in that it is closer to the finished piece. I still make my prototypes out of scrap wood or inexpensive wood like poplar and use plywood or MDF, but I develop the form further by actually roughing out the shapes of individual pieces such as the legs, back and seat.
This is also a good time to work out the joinery.
Let’s say that you are experimenting with how to join the front legs to the seat and you want to make certain that the joint will be strong enough to hold a heavy person. In a situation like this I will make one or two practice joints and test them. .If they break I’ll try something else. The advantage of having a prototype is that you can work out all of the problems and resolve them before going on to work on the more expensive wood. The prototype also enables you to create any forms or jigs that you might need.
For example, the tall back of this chair that I have designed (WoodWorks Episode 507 Contemporary Dining Chair), is a tapered bentwood lamination made from bubinga. Rather than cutting up some bubinga and hoping that the shape was going to work, , I cut several different profiles out of MDF until I arrived at a shape that gave me the lower lumbar support that I wanted while curving back out at the floor for the footprint that was necessary. .At the same time I could experiment with the height and width of the back. With MDF, it is so inexpensive that any shapes I didn’t like could be thrown out. Once I arrived at the finished profile, I could then trace the profile onto another piece of MDF and then band saw it out and use that to design my bending form. Obviously this is a labor intensive process but chairs are usually built in multiples so the effort starts to pay off after you have built six or more.