Mine is just one more DIY chair based on an ancient design, but I added a few features that you might find useful for when you build your version - like rubber feet and a sneaky paracord attachment setup and a seat cushion and an eight-legged horse.
Step 1: Inspiration
This chair has been called by a variety of names, so you won’t get a definitive pile of results from the interwebnets using just one search term: you’ll want to try Bog chair, Stargazer chair, Viking chair, Celtic chair, Plank chair, One-board chair, African chair, or Boy Scout chair. But a quick image search will give you the idea: two pieces, collapsible, and you sit on one piece and lean back on the other. This particular Instructable inspired me a few years back, but a plank of sufficient dimension never manifested itself. Then I saw this 'ible and decided I should make one using my copious collection of plywood scraps. But it wasn’t until I salvaged a palette that turned out to be made out of skinny strips of nice furniture-grade plywood, that I finally decided it was time to build my own chair.
Like most of my projects I considered this a proof of concept, because even though this concept has been proven for thousands of years by millions of people, I’d never sat in one. So I figured if it ended up being uncomfortable I’d just take it apart and use the wood to reinvent some other wheel. The thing is, this chair is great. I was about to buy a new chair to replace my elderly fold-out one, but this ended up becoming my go-to for the campfire, and it was free!
Step 2: Build
All you really have to worry about with this chair is whether the hole in the backrest allows the seat slab to slide in and stay put, and you can pretty much make up all the rest of the rules. I settled on the geometry that I thought would work best for the wood I had: six pieces of heavy ¾” plywood, all 42” tall and either 7 or 6 ½” wide. I’ll spare you detailed measurements because you can easily internet those up for yourself, and because I was being bossed around by my materials and you’ll likely have a very different experience. That is, unless you too are using skinny strips of plywood... but that would be really dumb, don’t you think?
For each half of the chair, I butted two equal strips of plywood next to each other and placed a third piece centered on top. Several 1” galvanized zip screws later, I had both “blanks” ready to go, with the screws only visible from one side. I rounded off both pieces and cut the seat piece down to size. I cut the rectangular hole in the backrest about a foot off the ground, about 1/8” wider than the thickness of the seat piece. My fit is pretty loose, but with carefully tapered cuts I’m sure a much tighter fit could be achieved. In any case, I was able to easily slide the seat into the backrest and test out my new chair right away. It needed some cleanup, but it was clear that the experiment was a success! The angle is great, and on its maiden voyage in my living room I watched a whole movie sitting on it, albeit with a folded towel as a cushion.
After a backyard fire pit test on the 4th of July (on much rougher terrain than my living room carpet), I decided to hack a half circle from the base of the backrest to make two distinct “feet,” a feature I’d seen in most designs but had decided to skip at first. It ended up looking better and adding a great deal to the stability. But in my case it subtracted from the thickness, so I compensated by adding the pieces I’d cut from the base to the outside of the newly-created feet. I chopped off the excess and rounded all the edges with a router.
Step 3: Fortification
I added some protective rubber from a bike inner tube to prolong the life of the three points that contact the ground, using staples and covering only the bottom edge and back surface, so the rubber isn’t noticeable when the chair is set up. I'll replace the rubber if it ever gets too abraded, using either more inner tube or something more robust.
Step 4: Transport/Storage
The two pieces of my chair were quite cumbersome to carry, so it was clear that I needed a way to corral them for transport. Many of these chairs just flop around as separate pieces when not in use. That’s fine if they’re just living in the back of a truck or if they have handles that line up so you can carry both pieces with one hand, but I’d gobbled up the most convenient place for a handle with the design I’d decided upon (see next step). Many chairs have features that allow the seat piece to attach flat to the backrest for easy transport, but I didn’t want to add thickness, or use clunky hardware like latches.
I finally settled on a paracord loop with a wooden toggle and slide which hold the parts together tightly, strung through the existing hole in the backrest and a keyhole-shaped hole drilled through both parts. When the slide is farthest from the loop, the toggle has just enough slack to fit through the keyholes, and it all tightens up as the slide moves back toward the loop. That worked well, but I later swapped the wooden slide for a leather one, which lays flat and holds a bit tighter.
A handle cut into the backrest provides a balanced carrying point. I was going to stick with only one handle, but the lack of symmetry was driving my family members nuts so I made another one on the other side to appease them. I paracorded one handle for comfort, and eventually did the same to the other handle. A stuff sack from a bygone sleeping bag performs double-duty as protection during transport and a holder for a seat cushion, but it's kind of ugly so I need to replace it with something with a bit more style. Any suggestions?
Step 5: Aesthetics
I knew this would be used outside so I wanted to stay rustic, avoiding any kind of snooty finish that I’d worry about damaging. But I was also inspired by the truly beautiful carvings on chairs like these that I’d seen on the interwebnets, especially the Celtic designs like this and this and this. I happened to have a few designs that I’d gathered for a local musical production of “Das Barbecu,” a Texas spin on Wagner’s Ring Cycle (yes, it’s as silly as it sounds!). My character was Wotan, another name for Odin, and there’s so much compelling Norse iconography out there that I went a little overboard on the details in my costume and props. Part of the going overboard was a belt buckle I’d made with my spin on an image of Odin’s 8-legged horse, Sleipnir. Since its outline was the right shape, and since I was one of a small handful of people on earth who’d ever seen that belt buckle up close, I figured it was the perfect candidate to put on the backrest. I wanted something on the seat part too, so I went with the “horns of Odin” symbol. So both parts of the chair have related designs that fit their allotted space and look nice. At first I wasn’t sure whether I’d be painting or carving or woodburning or staining, but I penciled in the designs anyway, transferring the outlines from printer paper using the highly technical “scribble on the back, trace on the front” method.
Finishing: I wanted to leave the seat mostly unfinished since it would be sliding against the hole in the backrest, but I wanted the chair to look like a complete idea (at least from a distance). So I ended up carving out the negative space in both designs using a rotary tool and adding black paint. Finally I added one coat of satin-finish Varathane, which nicely brought out the grain of the wood.
Step 6: Performance
A visit to the left field grassy picnic area at a Humboldt Crabs game (a real nail-biter at 16-1!) validated the decision to add rubber – my chair escaped with no grass stains at all. Then we brought the chair (fully-functional but still unfinished) on a nine-day vacation up the west coast (Eureka to the San Juan Islands and back) and used it at every campsite, during which it was referred to by my family as my “nerd throne.” Along the way I bought a scrap of thick leather (from the fine folks at Tacoma’s Tinkertopia!) for the new paracord slide and decided that a bit more seat cushion would be worthwhile, but overall it was great during the trip: much better than a standard camp chair for playing guitar around the campfire, and easily storable for travel. My only complaint was (and is) the weight: the plywood is a bit heavy. Not much can be done about that on this particular chair except putting a lot of holes through the surfaces, risking uglification and weakening. Using a different variety of plywood or any kind of lighter solid lumber could of course reduce the weight considerably.
Step 7: Further Development
Gravity does the bulk of the work in holding this chair together, but for even more stability, a keyed mortise-and-tenon joint could be used: a square gap in the seat plank right behind where it crosses the backrest could accommodate a wedge-shaped pin that would secure the pieces tremendously. Even better, that pin could also be sized to do double-duty as the toggle for the paracord loop! I may do that with this chair, or save that idea for my next “nerd throne.”
Step 8: On Eight-Legged Horses
I decided to let this Sleipnir design gallop off into the wild with a Creative Commons license (Attribution-Non-Commercial-Sharealike). So if you like it, feel free to put it on your own stuff (that you’re not selling, of course), or find pre-Sleipnired stuff here: zazzle.com/mikecdesign (I just bought the flask). And please do share a photo if you end up using the image, I’m curious to see where it might show up!
Thanks for looking!