Old doors make great tables -- they're the right size and shape, and usually made of good solid wood instead of that hollow-core nonsense you find in houses today. The only problem is finding a way to flush out the panels so the surface is continuous and flat. I have seen tables that fill the panels with glass, or cut wood, but I decided to mess around with some concrete instead. You can't use normal Quickcrete in such a thin-set application, but I found that some expansion or anchoring cement (such as Rockite) works pretty well. Throw some modern, angled legs on it, and you've got a sexy little work or dining table.
I salvaged all the wood in this project, but screwed up the concrete bit, twice, so that cost a little bit. Between screws, polyurethane, and concrete, it should run about seventy or eighty bucks.
You will need these materials:
An old panel door, preferably solid wood
4 3'-4' pieces of 2" x 6"
6 24" pieces of 2" x 4"
40-60 lbs of thin-set anchoring/expansion cement
1" drywall screws
3" drywall screws
You will need these tools:
Grinder (optional for polishing concrete or grinding down if you over-fill)
First five photos by Mr. RaMell Ross (http://www.ramellross.com)
Step 1: Legs!
First, lay out your door on the floor or some saw horses. Pull a centerline in each direction. You will have to adjust dimensions to your own door, but I put the leg attachment points at about 1/4 of the way in from each end of the table.
My legs were salvaged rafter tails from a demolition project, so they'd already been cut to a taper. If starting from scratch, cut up some 2" x 6"s to about 45", then split them diagonally with a circular saw, bandsaw, or jigsaw.
Then lay them on the door from your attachment point out to the corners of the door and strike a line on the under side of the door. Now you've created a triangle from the 1/4 centerline out to the corners of the door. Measure the angle of the point of the triangle and use that to cut two triangles out of scrap 2" x 6". These will become the attachment points for the legs. Screw and glue them to the door from the top, pre-drilling with an 1/8" bit to prevent splitting.
Hold a leg up to the triangle with the other end in the air and adjust until the foot seems to be roughly in line with the corner of the table. You might need a helper on this. Strike a line on the leg to get the miter where the leg meets the table. Cut all your legs to this angle. Screw and glue the legs to the attachment triangles with 3" screws, pre-drilling to prevent splitting.
Do the same with the leg braces -- just hold up a scrap of 2" x 4" and scribe the rough miters, then cut one and trace it onto the other four. The legs will still be pretty flexible and wobbly at this point, so push and pull them as needed to make them line up with the corners of the table. Toe-screw and glue the braces in with 3" screws, pre-drilling to prevent splitting.
Step 2: More Leg Stuff . . .
A work table or desk will want to be about 30" off the ground, a dining table a little lower, like 28"-ish. Flip the table up on its legs and see how high it sits; determine how much needs to come off your legs to get it at the appropriate height. Mine conveniently needed to come down about the width of a 2" x 4", so I laid it on the ground and scribed a line across the leg, flipped the table, and cut all the legs down. This is a simple way to get the angle of the feet right.
Next, to brace the legs off of one another, miter a 2" x 4" to fit between each pair of legs where the other braces come in and screw and glue it into place. The leg structure should now be extremely sturdy, without a trace of play.
Step 3: Concrete Prep
To hold the concrete in the depressions, punch a bunch of 1" screws in from the underside of the door. The concrete will flow around and grip the screws to keep it locked into the panels. My screws ended up slightly too long, so I had to grind off the ends of each one a little bit.
Sand down the door with an orbital sander, rounding off the edges of the door and legs well.
Set the table up on a level surface, shimming the legs as necessary to get the top as level as possible in both directions.
Step 4: Pourin'
To successfully pour in such a thin-set application without cracking, conventional concrete will not work very well. The aggregate is too big and the ratio of cement to other ingredients too low. Expansion cement is used for setting railings and bolts in concrete because, as the name suggests, it actually expands as it cures. This means you can drill down into an existing slab or stair, stick a bolt in the hole, and surround with with this stuff and it will expand as it cures, locking the bolt into the hole. Conventional concrete would shrink away slightly from the edge of the hole, making the connection loosen over time. For this table, expansion cement both resists cracking in a thin-set application, and won't shrink back from the borders of the panels.
However, it cures in 15-30 minutes depending on temperature and humidity, making it somewhat difficult to work with. I ended up over-filling my depressions, which led to me having to grind it down later, which cracked it a little. To prevent this, have a screed, or a piece of wood you can use to scrape the concrete level with the wood, handy. Also make sure you have enough -- the depressions seem shallow, but my door ate up 70 lbs of concrete. The product I used can be found here: http://www.quikrete.com/ProductLines/AnchoringCement.asp
Expansion cement is also self-leveling if you mix it slightly liquidy, which is why I suggested you level the table with shims under the feet.
So, mix up the concrete in batches in a bucket, wet but not soupy, and then pour it in. If you over-fill, screed it off, and be quick about it, because that stuff will set up on you in a minute.
Let cure overnight.
Step 5: Finishin'
Since my concrete set up on me and there was some over-filling, I ground it down with an angle grinder and a masonry disc. Try to avoid this! It was miserable, and it didn't turn out that great. Also try and find a better dust mask if it comes to that . . . .
Wipe down the table with a damp rag and then polyurethane the whole thing, concrete included. Once it was dry, I also lay two coats of wax on the top to protect the finish and prevent rings from cups.