RAMIFIED ARMCHAIR Poplar bendy ply and red oak veneer The seat is elegantly supported from the edges of the branching legs creating a bridge between the front and the back legs. The ramification of the legs not only split in two directions with the same angle to each side generating a consistent flow in the legs but also also creating the armrest. Interesting triangular windows become visible between leg-armrest-seat
by Alejandro Palandjoglou
sketches I knew from the start that I wanted to do a chair out of bend plywood so I started playing around the shape and with the continuity of the surfaces.
Making a full size prototype is helpful to check dimensions and proportions. Testing the ergonomics to verify if the angles and lengths are comfortable.
testing the material flexibility I tested the flexibility of the bendy-ply to know exactly the minimum radius I could bend the wood. After deciding the minimum radius was 3.2 inches I then went back to the CAD drawing and did some adjustments in the design so it could be manufactured.
The total material for my chair was 2 sheets 8x4 ft. of poplar bendy-ply of 3 mm and 1 sheet 8x4 ft. of red oak paper backed veneer. I got all of my material at Macbeath in San Jose for less than $100.
cutting all material
I started doing the male mold for the front leg. I decided not to use a female mold because I was going to be short on time and had to do 7 pieces in total. I decided to clamp the pieces down with just pieces of wood that spread fairly even the pressure of the clamps.
It was an easy and short bend of 90 degrees. I used regular wood glue and left it for 24 hours to dry. I put a thin piece of plastic over the mold for two important reasons, first, to make a smooth surface to bend, and second, to make it easier to unmold. Also As it was my first bend I used 13 clamps but after that I realized I could have probably used 8 clamps.
Bending the armrest was way harder than what I had expected because it took triple the time than the front leg. Of course, doing the mold was also more complicated. I believe this is due the 2 bends on the single piece. In addition, having long pieces to bend makes the setup and handling of the material more difficult. For all the bends I started using a plastic resin as a glue that was pretty easy to prepare but messy to work with. The resin got really solid and if it weren't for the piece of plastic the bent piece would be impossible to unmold. After I took the piece out from the mold I discovered that the bendy-ply wasn't very structural for longer pieces. It flexed more than what I wanted and got worried that the whole chair wasn't going to resist a person.
clamping Molds need to have parallel surfaces so that you can place the clamps. Clamping really tight is very important. The orange clamps worked better than the rest. Warning: don't do so much pressure with the same hand because you can get blood blisters in the palm of your hand.
Making the mold of the seat was definitely harder. I cut some strips of wood over the curve and then put some wood puddy and sand it down smoothly. As a female mold was going to be complicated I kerfed a piece of 他 fine plywood (only the part of the radius) up to the very last layer, spacing them evenly 7 mm away from each other. This created a flexible piece of plywood that I could easily use as a female mold. To clamp the seat to the mold I had to ask my wife for some help gluing the surfaces of the wood and also clamping it from the other end.
cutting the pieces and veneering
One the pieces were bent I sanded the edges and cut it 2 mm from each side so that it was squared and even. I then put some contact cement on the wood and on the veneer, waited for 20 minutes, and then stick them together. At first I clamped them down but I realized this was not totally necessary. Contact cement is really strong and will stick together and make it almost impossible to remove once it is done. Something tricky but everyone should be aware of. The veneer was cut slightly bigger than the piece and I later cut it with a knife.
After I had my 2 sets of legs I aligned them with some clamps and measured it with a 1:1 plan to cut it exactly where I had to cut the legs. I glued the legs together with 6 biscuits and let them dry for 24 hours. Finally I squared the 2 sets of legs so that they were identical.
assemblying One of the key parts of the process was the assembly. I had the two set of legs and had to glue them together with the seat. I measured where I wanted to put the biscuits and did the 3 holes in the back and 1 hole in the front of the legs. It was easy to glue using some parallel woods that helped me keep everything straight.
I did the finishing that Craig Millroy suggested. I heated Boiled Linseed Oil to 140 degrees and then applied it with a brush. Let it dry for a few hours and then remove it with a cloth. Then I added 3 layers of wax to have a nice and protected surface.
Detailed pictures of the manufacturing process.