We have been redesigning our front garden and part of the design that our friend and Landscape Architect Scott Graff calls for is a 5-foot garden bench in a round graveled seating area. As this area is being called “Barbara’s Secret Garden” my favorite client Barbara commissioned me to do the bench…Now! So I thought it might be nice to share the process here of building this bench.
About a year or so ago our good friend Chris was remodeling her home here at Sea Ranch and ripped out a pile of old-growth redwood interior siding. This material was in 5-inch T&G strips about 3/8-inch thick. I also claimed a nice redwood 2 X 8 with really nice tight grain. This wood had been sitting in our garage ever since so I thought that this project may be a perfect opportunity to put this recycled wood to good use. The siding was really only good for laminate bending and this also gave me the idea of building a rounded bench with laminate-bent seat slats. I thought that the curved bench would fit nicely in the small rounded seating area envisioned in the plan. (Scott originally thought of a bench with arms, but I didn’t think the arms would be as good a fit with this curved design and a slated seat…sorry Scott.)
So I played with a few iterations but the basic bench pretty much designed itself once I settled on a curved seat. I needed to quickly resolve the seat design/dimensions so I could get on with building a jig to do the lamination glue-ups. The design shown in the first figure below shows the overall concept of the bench. It carries some of the same design features as our floating-top bench so I liked the carry over between the two pieces. The seat slats and the back top rail are the reclaimed redwood while the 4 X 4 frame components are from a redwood mill. But I still consider this a rough approximation of the final design, as I’m sure once I get all the wood together and start the frame building process I’ll make a few tweaks in the shape.
Each of the curved slats that make up the seat are made up of 4 individual slats roughly 2.25” X 62” X 5/16” each. They are glued and clamped into a jig I built specifically for this project. The jig and glue clamping setup is shown in the next four images.
To make the jig I basically screwed 3 pieces of ¾” plywood together and drew out the arc I wanted for the seat curve. I then sawed the arc-line on the band saw which left me with a nice two-piece clamping press for the glue up process.
I use polyurethane glue on each slat, place it in the jig and draw the jig sides together with one clamp, as shown in the next image. Once the slats are in position, I use the pony clamps to really put the squeeze on, as shown in the subsequent image. If you look closely you can see the glue squeeze-out between the slats. I let the slats stay under pressure over night, and once the clamps are removed the next day you can see that the laminated slat maintains the curve of the jig with very little if any spring-back (last image).
Glue-laminating is a far more effective way to bend wood in my estimation as compared to steam-bending, which I have also done. Laminate-glue bending is far more predictable and has very little spring-back which can be a problem with steam bending. Using a hard-drying polyurethane glue also helps to minimize spring-back. I also could have just cut the curved pieces on the band saw from one large piece of redwood, but that would have wasted a fair amount of wood, and there would have been a lot of areas on each slat with short grain that could eventually crack, especially outdoors. These glued slats are quite strong because the grain runs along the glue-line. I have also used this glue (Gorilla Glue) for our outside light sconces which are all half-round and made up of many thin slats glued together somewhat like how a barrel is made. The sconces have withstood the coastal conditions here and are still in very good condition after twelve years out in the elements.
I should also say that using a clamp-type press is becoming a little old school, as vacuum presses are gaining in popularity among many woodworkers (did you hear that honey, all the other kids have vacuum presses?). But for me there comes a point where I just don’t have the space for one more tool. But, you never know.
So that’s where I am at the moment, and as I move along on this project I’ll post more details here. Naturally if anyone has any questions along the way, just let me know and I’ll try my best to answer them.
Finishing the Seat Unit
Once all the laminated slats were completed, I moved on to sanding and edging each slat. I also had to size each slat to its final length. Each slat was sanded to #220 grit and all corners were rounded with a ¼” round-over bit used in my edge trimmer. Finally, I also hand sand all edges to remove any machine marks from the router bit and to give the edges a more hand-sanded look. In the next three images you can see the final overall construction of the seat unit, which includes all 8 slats and three redwood cleats underneath that form the overall seat assembly. The front of each cleat was also rounded over with a ¾” radius round-over bit. The front edge of each cleat is also recessed about 1/8” in from the leading edge of the front slat. As you can see, the array of seat slats are held together with the three redwood cleats underneath, and each cleat has two deck screws fastening it to the slat above. This entire unit will be screwed to the bench base which will allow the whole unit to be taken apart for maintenance (like retightening screws) and/or refinishing.
The overall shape of the seat unit is determined by the curve of the slats; that is, the outer slat is 60” wide and tapers to about 52” wide at the front slat. The cleats and seat base (legs and stretchers) sit directly on top of each other so that the back posts of the bench are in the same plane as the slats and therefore the same curve can be used to shape the bench’s back rail. I’ve included an image here showing a t-square which gives gave me the correct position of the cleat which is essentially perpendicular to the tangent of the back slat at that point (bet you never thought you would ever need to use your HS geometry in real life, but there you go).
I’ve included the last image here to show you how the curve was actually drawn onto the clamping jig for the final shape of the slats. In actuality this curve is not a true arc as it is not formed from a true radius. It’s a true arc on the drawing, because that’s how the program draws curves, as an arc of a radius. But what is the same from the drawing is that the center of the curve is 5 ½” in from the center line. I use a pony clamp with a piece of wood the exact length of the slat, and pinch the ends until I get the 5 ½” center bend and draw the curve onto the plywood used for the clamping jig. This gives you a curve that is more flattened at the ends, and I believe a more pleasing curve than a true arc or radius. Using the pony clamps also makes it easy to fine tune the curve using the screw clamp to get the final curve exactly where you want it.
Next, I’ll start on the bench frame and work on constructing the bench back rail pretty much the same way the seat slats were constructed. I’ll have to get the bench assembled before I can actually fine-tune the fit of the back rail, but that’s another installment. Stay tuned.
Finishing the Leg Assemblies and Assembling the Finished Bench
Now that the seat assembly is essentially done, I can focus on the three leg assemblies. They are identical and use straight-forward mortise and tenon joinery. I prefer to cut the mortises first and then adjust the fit of the tenon for each mortise. Once I’ve spent the time to lay out each mortise, I used a Forstner bit first to hog out the center of each mortise, as seen in the following image.
This does a great job of removing most of the mortise material. Then it’s on to the mortising machine to true up the corners, as seen in the next image.
After the corners are finished, I use chisels (see image) to true up all the sides and to final-fit and match each tenon to a specific mortise. Over the years I’ve found that the extra effort of matching each mortise with a particular tenon assures a much better fit overall in the finished piece. I was going to show you the tenons but somewhere along the way I lost those images between my shop and the computer.
Once I had all the M&Ts done, I rounded over all the edges with a ¼” round over bit. I also reshaped all the leg components adding the arch to the bottom of the center stretcher, and slanting the front face of the back leg and rounding over the top of the leg. I also decided to round over the all the leg joints as well, as I felt that any subsequent gaps in the joint due to weathering would be far less noticeable, and I think it added a nice design feature as well. I also used a 1” roundover bit to round the corners of each leg bottom. Now I just had to glue up the leg assemblies using polyurethane waterproof glue.
The only piece of the bench left to construct now was the back rail. Essentially I just rebuilt the glue-press jig I used for the seat slats so it would handle the wider 5” slat pieces that make up the rail. Once all the pieces were planed and sized correctly, the five slats were glued up in the press and prepared for final fitting. I cleaned up the edges, and shaped the ends according to the original plan I designed. I also rounded over all edges as in the other components.
Once all the basic components of the bench were essentially done, I sanded each component to #220 grit. I usually prefer to assemble a piece final before I put finish on it, but because this bench was going outside, I wanted all surfaces to have protective finish on it. So I applied one coat of Messmer’s UV-Plus Natural Redwood Finish to each component, as seen in the following image.
This type of finish is not a “Build” finish, in that it doesn’t result in a film-type finish when cured. It’s an oil finish which penetrates the wood and provides UV protection and some protection from the weather. The benefit of a finish like this is that it can be reapplied without removing the prior coats, at least for a few years. This is an experiment, so I’ll keep you posted on its efficacy long-term.
Now that all the components are oil-finished, I did the final assembly as seen in the following photograph.
I used #10 stainless steel deck screws to assemble the components. This will allow me to retighten the screws over time if/when the components loosen due to weathering. I can also take the major bench components apart if I need to refinish or repair it.
The following two images show the bench in its final place in Barbara’s Secret Garden. You can also see how the curved bench lines coordinate with the curve of the gravel pathway. Many different styles of bench would have gone here, but paying close attention to the details of where a piece is going to be used is an important part of the design process. Allowing the curved path to play an important part in driving the bench’s design I think made the difference between a nice bench and one which really looks like it belongs in this setting.