A customer brought 7 teak dinning chairs to us for repair and reupholstering. In addition, they asked us to make them a new chair to match.
For the new chair, we started with the bottom to ensure we would be able to bend the seat into the form needed, while still maintain the integrity needed to withstand the weight of a person. After several attempts, we found a material that could be glue laminated, formed and retain the needed strength.
Once we confirmed that we could make the seat bottom, we moved on to reverse engineering the chair, starting with getting measurements and creating templates to measurements.
We then turned our attention to figuring out how to steam bend the lumbar support slats. We had to start with building a steam “box”. We accomplished this using a PVC pipe, a Wagner wallpaper steamer and dowel rods.
We planed a board of Iroko to 3/4″ thick to create the width of the slat and then used the band saw to cut the slats to the thickness. Steam bending needs to use quarter sawn wood. We made a form to bend the wood to the shape needed. Our first attempt didn’t take in to account enough of the spring back once removed from the form so we had to create a new form and bend a new piece. We then had to wait for it to dry before removing it from the form. Success!
Or, maybe not!
We cut the six slats we needed on the band saw, sanded them down and then sent them through the router to round over the edges (have I mentioned there isn’t a flat surface on these chairs anywhere?). We decided to be brave and steam two slats at a time and then put them on our form to bend. That is where things went wrong and one of the slats cracked because it didn’t have enough moisture. So, back to the design of the steam box to improve the design and create a more consistent steam. Mark decided to use a copper pipe with holes in the top to force the steam all the way to the end of the PVC pipe. The pipe was fitted with some brass rings and a new end cap was created to help prevent some of the steam from leaking out. We also increased the amount of time we left the slats in the steam box to 45 minutes. Our first attempt at steaming two more slats had better results, however we found that one of the slats didn’t get as much moisture so it had a hard time bending and generated some smaller cracks. Before steaming the next set of slats, we’ll make the holes in the copper pipe a little bigger to help make sure the steam gets distributed equally when there are multiple pieces of wood in the box. Hopefully, the next set of slats will both bend successfully. Stay tuned!
We were able to get two more of the slats steam bent but have had problems with the others cracking. While waiting for slats to bend and dry, we’ve moved on to making some of the chair parts from the Iroko (African treak). Since some of the boards were warped, we started by using the jointer to get a flat side on the board. We then used the Woodmaster planer to bring the boards down to the correct thicknesses. We laid out the parts to determine the best usage for each piece and started cutting the boards down to size. Below are the front and side aprons as well as the front legs. They need to have the radius cut to get the rounded edges, be hand sanded and then they will be ready for stain.
The top and bottom rails need to have holes in them to embed the slats in. Templates were made to get the location of the holes for both the top and the bottom rails. The holes in the template were cut with a mortising bit and then cleaned out by hand with a chisel. The holes are checked for fit with a slat.
The template is then added to a jig that will hold the rail block in place and then taken to the pin router to cut the holes in the actual blocks of wood. The template sits on the bottom of the jig where the pin will allow us to trace the holes. The router bit sits in an overhead arm. Once the depth of the bit is determined, the table top is gradually raised to cut the holes. The holes are tested for fit with the slats.
While Mark works on the next template for the bottom rail, I start playing with some stain to try to determine how to come up with a color that will match. We start with 3 coats of natural cherry polyurethane but decide it is a little too light, and red, so we add two coats of antique walnut to try to bring down some of the red. It is a close match but we might try again with a little darker walnut.
After the holes are cut for the bottom rail, it is taken to the band saw where the block is cut to create the curves. After the first cut, it is taped back on to the piece to keep the block flat for the other two cuts. It’s then checked for size and shape. It’s ready for the router to put the radius on the edges and then hand sanding and stain.
Next, we moved on to the back legs. Because of the curve in the leg and the weight the legs need to support, we needed to cut the legs from two pieces of wood so we could control the direction of the grain in the wood. We used a Freud finger joint bit to provide the maximum amount of wood surface to glue the two pieces together.
The front legs were then hand carved and sanded to the proper shape and size.
The top rail is also hand carved and sanded to almost the final shape. A little is left to enable Mark to do a final blend of the chair back legs to the top rail.
Meanwhile, back to the saga of the slats. After several more attempts get steam bend the Iroko slats, we only had a couple slats that we could use. The slats were either splitting during the bending process or they were skewing to the side. We decided to try cherry instead of the iroko since it bends easier. Since we were still having issues with the cherry splitting, we decided the wood just wasn’t getting enough moisture in them so set out to build a better steam box. This time, we built it out of wood and kept the size of the space smaller. We also decided to use a propane heater and larger tubing to pump more steam in to the box. While the iroko was still splitting, we were able to successfully bend the cherry and have chosen the final six pieces to use. We’ve done testing with the staining of the cherry to ensure we can get the color the same.
Now that we have all the pieces cut and shaped, it’s time to start putting them together. One of the concerns was being able to get the holes for the dowel rods located correctly and to drill the holes in at the correct angle. We decided to make a jig to help. We had a block of aluminum that we cut in half. We then took it to our CNC milling machine and cut the edges to make sure it was straight and then started cutting it to the shape needed.
We then placed the jig on the various pieces of the wood to drill out the holes on the rail pieces. To get the correct placement of the holes on the legs, we took a dowel and cut it in half. We then inserted small nails in the end so that when we pushed the rail against the leg it would leave two small pin holes where the center of the holes should be. We then hand drilled the holes in the legs.
And then it was time to start gluing. You know things are getting close when there’s glue involved!
For the back, we decided to glue up just the bottom rail first, while assembling the other pieced to help it keep the correct shape while it was glued and drying. The slats where each fitted for size and to ensure the retained the correct curve. The top rail will be fully fitted to the back legs once the back rail has dried.
At last, the final touch is drilling the holes in the seat for the cushion.
And after 3 coats of cherry stain, several coats of dark walnut and carrington stain and 3 coats of polyurethane we have a completed chair.
The model chair is also repaired and ready for delivery. Any guess which chair is the original and which is the new in the following pictures?
At last the set is complete and the new chair finds it’s place at it’s home.
PS… In the picture with no seats, the chair on the right is the new chair. In the picture with seats, the chair on the left is the new chair. In the chair in its new home, the last chair on the right is the new chair.