Sand the tiles.
The marble tiles I bought from home depot had a high gloss finish. I am not the biggest fan of high gloss finishes so I used 400 grit paper on my orbital sander to give the stone more of a natural honed finish. I also smoothed down the edges of the tiles.
Cut the tile.
I set up the saw and filled the reservoir with water. The water keeps the blade from getting too hot and also keeps the dust under control. I set the rip fence to about 3.75” and cut strips of the tile. It was really easy but you can’t go to fast. I just tried to slowly feed the stone through the saw and let the blade do the work. For the longer 24-inch tiles it might be nice to have an extra set of hand to catch the long pieces as they are pushed through. I cut 5 pieces to assemble a long box.
Glue the pieces together.
I used liquid nails to glue the pieces together. I didn’t want to have to clean off lots of adhesive off the exterior so tried to be careful not to use too much adhesive. Gorilla 2-part epoxy also works well but is a bit more expensive. Make sure to even spread the adhesive on the edges and then wipe off any exterior adhesive on the outside.
Clamp it together.
For the first planter I used C-clamps and screwed them a little too tight. I caused a small crack in one of the planters. The crack was small so I was able to seal it from the inside with liquid nails. For the 2nd planter I used rubber bands to hold it together and that worked really well.
Let the glue dry.
I let the glue dry overnight before removing the clamps and testing to see if the planters held water. If they leak simply caulk the interior seams with liquid nails or construction adhesive.
Sand the edges.
The edges for one of the planters were a bit sharp so I put a drum sander in my drill and rounded them down
Put in some plants.
I didn’t want to put drainage holes in the planters so instead I put about ¾” of gravel in the bottom before filling them with soil and plants. I am using them for decorative plants and wont put in edibles until I am done researching non-toxic adhesives or figure out a way to mechanically fasten them.