Make A Pair of Slat Chairs

A winning combination of form and function — this outdoor chair is comfortable and lightweight, and it features a modern style that makes a statement.

The design for this patio chair has been coming together in my head for a long time. I think of it as a cross between a park bench and an Adirondack chair. I'm not fond of Adirondacks; I find them too hard to get in and out of. My adaptation feels more like a regular chair. It's rock-solid, easy to build and unusual-looking enough to be a conversation starter.

I spent a lot of time adjusting the prototype to make it comfortable and to achieve the look I wanted. (I considered adding arms but decided they would detract from the unique all-slat design.) The holes in the tops of the sides are handholds so the chair can be easily grabbed and moved. The chair is made from cedar, which is rot-resistant; I left mine unfinished so it would weather to a natural gray color. You could apply exterior-rated stain or finish, but keep in mind that there are a lot of hard-to-reach surfaces that will be difficult to finish.

Construction notes
You can expect to spend about $100 for materials and eight hours on construction. You'll need a table saw, a jigsaw, five 18-in. bar clamps, three 36-in.-opening pipe clamps, one 24-in. bar clamp and another 24-in. clamp that can be converted to a spreader, a pneumatic brad-nail gun, a router, a top-bearing pattern bit and a 1/8-in.-radius roundover bit (see SOURCES in PDF below). I also employed a surface planer because the cedar that I bought at my local home center was 7/8 in. thick and one face was rough sawn. I used the planer to remove the rough face and make the wood 3/4 in. thick. It is possible to build the chair without planing the wood — just orient the rough faces to the back, bottom. etc.

The sides of the chair are cut from large blanks of edge-glued cedar boards. You must use waterproof glue to create the blanks; otherwise the chair will fall apart when exposed to the elements. The slats are fastened with water- proof glue and galvanized brads set with a pneumatic nail gun. Don't be tempted to forgo gluing the slats to the sides — gluing is essential to the strength of the chair. When you're gluing the parts together, use a damp (not wet) rag to remove excess glue. (Dried glue is hard to sand off.)

Working with cedar can be frustrating. I bought construction- grade lumber to save money. It had a lot of knots, some sapwood (very light color) and some separations along the growth rings. Working around these defects takes time and planning. Carefully decide which board to use for each part. Any included knots must be tight and small. Don't use boards with knots or defects for the 3/4-in.- wide slats (C4), and make sure that all of the wood you use is structurally sound. I wound up with about 25 percent waste, which is not un- usual with low-grade cedar.

Creating the template
The shapes of the sides are routed using a pattern bit guided against a 1/4-in.-thick plywood template. You have two options for making the template. If you have access to the Internet and a copy center with a large-format printer, you can download the full-size PDF (download the PDF here), send or take it to the copy center and have it printed. The printing instructions appear on the PDF file. It cost me $7 to print the pattern full-size — well worth the minor expense.

To mount the printout on a 1/4-in.-thick x 36-in.-square piece of hardwood plywood, first apply a light coat of spray adhesive to the paper pattern and to the face of the plywood. Let both pieces dry. Cut a 36-in.-square piece of cardboard or poster board. Lay the cardboard on the plywood and the printout on the cardboard. (The dried adhesive won't stick to the cardboard.) Slowly pull the cardboard out and press the pattern onto the plywood. The two surfaces with the dried adhesive will stick to each other.

The other option is the low-tech, old-fashioned method of transferring the small grid pattern to a larger grid by hand. Draw a 2-in. grid on a 36-in.-square x 1/4-in.-thick piece of plywood (photo 1). Referring to the illustration (in PDF, below), mark the points where the shape intersects with the grid; then connect the dots to create the shape.

Lay out the 2-in. grid on a 36-in.-square x 1/4-in.-thick piece of plywood. Mark the intersection points shown on the original pattern; then connect the dots to create the shape. A poker chip is the perfect diameter for drawing the radius on the bottom corners of the legs.

Once you've transferred the pattern to the ply- wood, drill a starter hole for the handhold. Using a jigsaw, carefully cut out that opening and the shape of the sides; then sand the sawn edges smooth. Take your time — your chair sides will only be as good as your template.

Making the sides
Once you've completed the template, cut pieces A1 and A2 to size (see cutting list in PDF, below). You'll need to glue together three A1 pieces for each side: First glue two pieces and let that joint dry; then add the third piece. Next, working with the faces up and using pipe clamps (photo 2), add the A2 pieces one at a time to the side panels. (Cedar is too soft and pliable to use bar clamps for this step — I tried, and the assemblies just kept popping apart under pressure.) Keep in mind that as you work with the faces up, you need to add the short pieces to opposite ends of the blanks so that you create both a right and a left side blank.

Use pipe clamps when you glue the short upper pieces to the side panels. Place two clamps underneath and one on top. To prevent the metal from staining the workpiece, cover the part of the pipe that touches the glue joint with masking tape.

Align the template leg bottoms with the bottom edges of the side blanks and trace the shapes onto each blank. Use a jigsaw to cut out the shapes. Cut close to the lines, but leave 1/16 in. to 1/8 in. extra to be trimmed away when you rout the shape. Be very careful when handling the sides; at this stage they are very flimsy. Next, make the stiffeners (B1, B2 and B3). Use glue and 1-1/4-in. screws or brads to fasten the stiffeners to the inner faces of the sides. Once the stiffeners are in place, the sides will be much sturdier. The stiffeners also raise the sides to make routing easier. Align and clamp the template to each rough-cut side and rout the shapes (photo 3).

Rout the shape of each side using a top-bearing pattern bit (see SOURCES in PDF below) guided against the template. Use a lot of clamps to secure the template in place. You'll need to move the clamps as you work to complete the routing.

Assembling the chair
Make all of the slats (C1 through C4). Cut a few extras of each size in case you find a few bad ones during assembly. Round over the top edges (photo 4); then finish sand the slats.

Round over the top edges of the slats using a 1/8-in. roundover router bit (see SOURCES in PDF below). Ganging the slats to rout the ends greatly speeds the work.

Draw slat-alignment lines across the outside edges of the chair sides (photo 5). Space the lines roughly every 5 in. These guides will help you to space the slats evenly and keep the slats perpendicular to the sides.

Align the two sides face-to-face, and use a combination square to draw lines across the outside edges. These lines are visual aids for keeping the slats aligned as they are added.

Set the sides upright and temporarily clamp a C2 slat at the outside bottom of the front and rear legs. This defines the spread between the sides and holds the sides so that it's easier to attach the first batch of slats. Position the first slat (C1) tight in the corner be- tween the seat and the back; then fasten it with glue and nails (photo 6).

Glue and nail the first slat in place using a pneumatic brad nailer and 18-gauge x 1-1/2-in.-long galvanized brads. Place two brads at each end. Use a damp rag to remove any excess glue before it dries.

Attach the next few seat and back slats (photo 7). Finish adding the seat top slats, including four C3 slats. Use one brad at each end when attaching the C3 and C4 slats. Then lay the chair on its back and add the rest of the seat back slats (photo 8). Continue adding slats, being careful to attach the correct number of C3 and C4 slats in the proper sequence. Flip the chair over and add the back slats (photo 9). Flip the chair over again and add the remaining front slats.

When adding the slats, you may need to spread the sides apart a bit so the slat ends are flush with the sides. Use a spreader clamp to do this.

As you add the slats, you may need to pull the sides closer together so the slat ends are flush with the sides. Use a 24-in. bar clamp to do this.

As you add slats near the leg bottoms, you may find that you need one more or one less C2 slat to complete your chair. (This would result from a cumulative spacing error, but it's nothing to worry about.) Stop adding slats when the next one would cover any part of the radius corners of the leg bottoms.

All that's left is to finish sand the chair sides and any remaining unsanded surfaces and smooth all sharp edges. There's no need to fill the nail holes. Your chair is ready to take outside and enjoy.