I have some old shelving from my last apartment sitting around, and decided the other day to put some of it to work.

Today, I cut one of the shelves up and screwed it back together in a different shape with exactly 0 planning, and now I can use my computer standing!

I point out the “0 planning” bit because what follows is an account of building the desk, replete with some really ridiculous conundrums that could have easily been approached better or avoided entirely with a little foresight.  But I just wanted to build something; to hell with logistics.

It was pretty simple to put together and I made a real hack job of it (big surprise), so it only took a few hours including lunch.  And, it was free! – it only took 1 unused shelf, a couple old little wooden garden stakes, and some screws.  (Here’s a timelapse video of the process.)

I wanted the legs of the table about 13.5″ high so the finished desk would be about 14″ in height.  (Note the frequent use of the word “about.”)  So I stood the shelf on end and measured 13.5″ and 27″ from its edge, drawing guide lines using a level.  (I realized later that the garage floor itself isn’t level, so my lines were in fact somewhat slanted… but not enough to make a big difference in the end.)  I used an old hand saw to cut along the lines, creating two 13.5″ tall legs.  I flipped each of these and cut it in half along its length, making four legs.  The shelf was about 11″ deep; I did a pretty slop job of cutting the shelves in half, so two of the legs are around 5″ wide, and the other two are around 6″ wide.

I tested the legs for straightness by standing them on the floor on either end to see which end was the least wobbly on each leg.  Only two of them had no wobble at all, but for the other two I devised a little trick:  by sawing a shallow little arch or long notch in the middle of the edge (so shallow you can’t really even see it), leaving about an inch to half an inch of straight edge on either side of it, you can ensure it won’t wobble by giving it two smaller contact faces rather than one long one, which makes it less susceptible / impermeable to wobble.

I figured about 30″ was a good width for the desk.  I didn’t really measure this against my actual desk; I just decided my desk surely must be wide enough to accommodate a 30″ upper-level easily and hoped for the best.  (Worked out fine, as is evidenced by above photo, just so there is no mystery.)  I lined and cut 30″ and 60″ from the edge of the shelf, which left just a little of the shelf left.

I picked the less-ugly face of each 30″ board, and laid them down side by side, pretty-ish faces down.  The two boards had to stay together because there wasn’t going to be a leg between both, so I took the little shelf left-over chunk, cut it in half, and straddled the boards with them.  But then I realized I couldn’t figure out how to screw these braces to the bottom of the desk.

Ultimately, I put down the brace-boards first, then laid one desktop board over them, face up, screwed that to both braces, then did the same with the other.  I decided it was done and went to set it aside, but the desktop wouldn’t move.  I had actually ended up screwing the desktop straight onto my work table because the screws were a fair bit too long.  Duh.  You can see them poking out in the below picture.

I sawed a thin garden stake in half, and then half again, backed out the desktop brace screws a little bit, scootched the desktop over so it was hanging over the edge of my work table, held the garden stakes in place under the holes where the screws had popped out of the bottom of the desktop, and pushed the screws down through the garden stakes.  I probably looked ridiculous, trying to accomplish holding the desktop in place and up against gravity, setting a screw, using a power drill, and holding the bits to be screwed to the underside, all at once and with just my two arms.  Anyway, I went through the trouble just so I wouldn’t stab myself later and curse; great success visible below.

I decided to attach the legs in the shape pictured below for stability.  If I make another, the back legs will not be at quite such an angle; there isn’t any wobble or backwards flex as it stands (heh heh), but I think it’d probably be a little less likely to fall backwards and break if the back legs were a little straighter, pointed more back-to-front than side-to-side.  Note: I recognize my sitting desk is a mess.

Attaching the legs to the desk was the part that could have most used some planning, though.  I had no vice, no assistant, and no experience.  In fact, I don’t even know if a vice would have helped.

So, naturally, I took the most straight-forward and ridiculous approach possible of balancing the desktop on the legs while they stood precariously upright on the ground, and eyeballed my screw angles.  It shouldn’t have worked, but it did.  Without one misfire.  What wonders never cease.

One snafu: one of the legs, somehow, ended up about .5″ shorter than the others.  I took the tried-and-true tack:  garden stake to the rescue!

The final desk does not wobble, and actually feels surprisingly sturdy.  Given that I did put a few hours into it, though, I might screw in some little metal braces underneath to keep the legs from buckling.  But this will presumably not happen, if luck’s got anything to do with it, until I have at least two glasses of liquid and a bowl of something stain-prone on it, so maybe avoiding such a scenario is a good enough defense.

Here is the rough proposal / guide I wrote that my friend Dan and I used to construct a cob oven.  Cob is basically an earthen mixture (clay, sand, water, straw or sawdust, with variations) that has been used for thousands of years as a construction material.  Mixed accordingly, it can have great thermal properties, eg. soaking up and slowly releasing heat (and sunlight heat energy!), or allowing cool air to similarly pass through.  Someday, I want to build a house of it.  Google “cob house” and prepare to have your mind blown.

Anyway, for now, Dan and I thought an oven would be a good introduction to cob, as its thermal properties make it a great outdoor oven option on the cheap/free; plus, it’s totally earth-friendly and all natural, and fun to build.  With this guide and maybe a little additional research, you should be able to make one, too.  Photos forthcoming!  Also, this is not edited or polished to be published.  I just felt like putting it up anyway.  (Note:  ultimately, we needed less detail/steps and less materials than this guide proposes to make our fully functional oven; we didn’t refer to this guide during the actual construction so we cut a few corners and still came out with a great product.)

The oven, after first cob layer

 In order to build an outdoor, wood-burning oven as cheaply and naturally as possible (while keeping durability and efficiency in mind), the process is designed around these ingredients:

 

• Clay / subsoil with a high clay content
• Sand
• Straw (or sawdust)
• Water
• Empty beer bottles
• Old cinder blocks / urbanite, or bricks, or stones
• Some firebricks, or more bricks (preferably the old red clay type) with at least one flat surface
• A large tarp
• Newspaper
• Cardboard (only as much as the mouth of the oven is big)
• Scrap wood and a few nails (for oven door)

 

Time required:

A bit less than a day of construction + a couple sunny drying days during cobbing

 

Cob is (for our purposes) a mixture of water, clay or clay-rich subsoil, sand, and straw. High thermal mass cob is a mixture of around 25% clay and 75% sand. The most insulative cob is a mixture with as much straw in it as possible while keeping a form-able consistency. By building an oven of both types of cob in two layers, we can achieve high heat efficiency and long cooking length.

 

Foundation: old cinder blocks, or stones, or bricks. Between three and four feet high (think of a good working height). Around two feet in diameter would provide space in the oven for around three medium-sized loaves of bread or one or two personal-sized pizzas, so we can make it a bit bigger if we wish.

The foundation’s outer ring of stone is filled in until the top ~4”, leaving a small pit at the top of the foundation.

First into these top 4” is a flat, thin layer of wet (but of form-able consistency) sand. On top of the sand are the beer bottles, laid on their sides, as a layer of insulation. The space around the beer bottles is filled in with more wet sand, and this layer is then covered with another thin layer of wet sand, made as flat as possible. This top layer of sand may need to be a little thicker if the oven floor bricks are uneven on their bottom face.

The firebricks or red clay bricks are laid out as the floor of the oven on top of this last layer of sand, flattest face up. Laying brick outward from the middle using the “kissing” brick-laying technique and then tapping the bricks flush ensures as flat and tight an oven floor as possible, which is important for heat insulation and cleaning. (A couple bricks may jut out in one direction as a lip to make loading and cleaning the oven a bit easier.)

Once the oven floor is done, a dome of wet sand is made on top. The dome’s center is at the center of the oven floor, and the dome’s height should be 75% of the dome’s diameter.

Working inwards from the outer edge of the dome (the circumference can be drawn using a string from the center of the oven floor), the wet sand dome is built until it is of the right height. The dome is then covered with strips of newspaper.

High thermal mass cob is mixed in the tarp. A ratio of 3 parts sand to 1 part clay is best. If subsoil, it should be certain that there are no organisms in the soil (no topsoil), as decay and rot can lead to some cracking. The clay and sand are folded and mixed on the tarp dry first as they’re difficult to mix when wet. Then, water can be added while the cob is stomped together until it is sticky enough to be form-able but not too liquidy – the consistency can be tested to be right by forming the cob into a ball and rolling it in the palm. The ball should be just sticky enough to keep its shape, but dry enough that it doesn’t pancake while rolling in the palm. If the ball is dropped, it should not go “splat.” The cob is then formed into small “loaves” or balls, which can be easily pressed into place during cobbing.

Also, an arched mouth of the oven is made by arranging and cob-mortaring bricks around a piece of cardboard cut and measured to represent the mouth opening. By a few accounts, the height of the mouth should be ~60% of the dome height so as to best draw cool air when firing. In one account, an experienced builder stated that he built his mouth at “a critical 63%” of the dome height.

The mouth of the oven can be put in place (over the brick lip if one was installed), and the thermal mass cob balls are formed around and pressed against the sand dome to create the inner oven wall, at a thickness of ~4 inches. This layer should be given a some time to dry.

After some drying time has been allowed, the sand can be dug from inside the oven. The newspaper strips over the sand dome provide a guide for when to stop digging as you’ve reached the cob wall!

Insulative cob is made as the outer wall layer. Thermal mass cob is made in the same way as described above. On the side, straw is chopped into smallish bits. It should be certain that the straw is straw rather than hay, that is, dead and dried, for the same decay/rot consideration mentioned before. (Sawdust can also be used). Handfuls of straw are then dropped and gradually stomped into the cob. Large clumps of straw are harder to integrate into the cob, so good practice is to “sprinkle” straw in front of you as you walk around in the cob and stomp it in gradually. Best consistency of insulative cob is a very high straw content while still form-able.

This layer of cob is applied over the thermal mass cob once that’s had some time to dry. A good thickness is between 2-4”. This cob is applied in the same way, but small finger holes can be made in the cob as it is applied. Subsequent cob “loaves” can be pressed into these holes so as to “lock” the straw together and better the overall structural integrity.

Using the scrap wood, make a little wood door with a handle to hold the heat after firing. The piece of rounded cardboard from earlier can be used to get the size right.

 

I’ve read that a natural plaster can be applied to the outside to help protect from the elements, like a lime-based plaster that would breathe and not cause cracking in the cob. This is also good for larger structure construction. For now (and even post-plastering), propping a tarp over the oven (especially before rains) is boranj!