-Rubber Mallet, Chisel, Wood glue, Large metal bar clamps, Shop rags, Panel or skill saw, Compound miter saw (optional), Orbital or belt Sander/ Sand paper 80, 120, 220, Wood filler and metal spatula (I MADE MINE AT TECHSHOP SAN FRANCISCO ---> techshop.ws)
Step 1 - Find or buy some tongue & groove lumber
This project started with a visit the Wooden Duck in Berkeley, CA just after their recent fire. Lucky for me their scrap wood dumpsters were full to the top with quality hardwoods of various sizes that was tossed due to excessive smoke exposure (note: they smelled like smoke at the time but about 4 days later had no trace of the smell). I dove in and noticed dozens of 3 ft+ long pieces with pre cut tongue and grooves that were about 3 inches wide and 1 1/2 inches thick. Any size will work as long as the length of each piece meets your final table needs. GREAT! I just scored a bunch of quality, pre-cut, FREE materials that I can make a table top out of but what next? Well, let me first point out a classic woodworking saying: what you save on materials, you pay for in labor.
Step 2 - Assemble the wood pieces and make sure they all fit into each other
The great thing about tongue and groove boards is that you don't have to use a dado tool or biscuit joiner to assemble them securely - so if you dont have those tools you just buy pre cut materials. The drawback to this is that each board - especially the free variety - might not always fit into each other due to wood defects like warping bowing or just wear. Start the process by laying out the boards how you think they'll look best then take a rubber mallet and start joining them together to check that they fit snuggly. If they don't, switch them around to see which work best together and then finally, when you have to use brute force, take a chisel and shave off the corners of the problematic tongue and grooves so that they connect easier then beat em hard with the mallet until they fit...if theres one particularly problematic one, you may have to bust out the large metal clamps that you'll later need to do the glue up. Wear gloves if you have them during this step... handling rough reclaimed wood = lots of splinters.
Step 3 - Glue Up the Boards
Get your wood glue and large clamps ready and make sure you have the boards laid out in the order you want them and that they fit (very important they fit once you apply glue). Begin by applying wood glue to the first joint on both sides... I like to apply a liberal stream then use and old paint brush to even out the coat over the entire surface of the joint. Join the glued pieces and use the rubber mallet to make them snug. Glue and join boards quickly in succession until you've done about half and then start the process over with the next lot of boards...this way it becomes less massive/less likely to fall over before clamping. When you get the two halves glued up and snug apply glue to the middle and join both halves... then get your clamps and start on the outside, clamping each side tight. Take a wet shop rag and wipe down the glue that came out - this will greatly help when sanding later. Then flip the assembled top and take one or two more clamps and clamp down the middle of the table. Clamping on both sides ensures there's no bow in the table. Wipe the glue off the other side now. If you see any bowing, first make sure you've clamped evenly on either side of the table and use the rubber mallet to beat that sucker flat if necessary. Leave clamps on overnight. Glue ups can be tricky so make sure you've studied up on them online.
Step 4 - Cut off ends to make a perfectly square edged rectangle and then any desired vanity cuts
Using the panel saw, cut off the ends of the table top to make a desired size rectangle. Then make any desired vanity cuts if you don't want a rectangle. For me, I went with an octagon using the compound miter saw set at 45 degrees.
Step 5 - Sand, Sand, Sand
Once you've got a nice flat glued up table in the shape you like, put it on a stable woodworking table and start sanding the top with 80 grit and sand it until you can barely feel where one board connects to the next. I like to sand with the grain about 70% of the time then 30% alternate going +/- 90 degrees and +/-45 degrees. Work your way up to 120 once flat and then 220 for a final smoothing. The bottom of the table can be sanded with less ambition, it's really up to you. I like to get it up to at least 120 grain and make sure there's no splinters whatsoever. I also like to sand the edges consistently as if they were rounded off by a 1/8 in router bit.
Step 5 - Apply hard drying wood filler to any final cracks
Once up to 120 or 220 grain, you can apply wood filler to any cracks that exist. I do this since this will be a table top where food will be eaten. So take a metal painters spatula and apply that stuff liberally to any crumb catching cracks. Do the same on the sides where the tongues/grooves meet. You can sand off the excess with 220 after about 15 minutes of drying.
Step 6 - Finish your table top
Apply your finish of choice. For this project I'm going to seal the wood with a natural color floor sealer then apply 3+ coats of water based polyurethane, which will protect this table for decades. Choose some cool legs and screw on your finished table top. And FINALLY...have a dinner party to celebrate your new table!