After the paintings were finished, I gathered up the supplies to make the coasters. I have a box of 3.75"x3.75" white tiles left from the last set I made. I also cut up pieces of thin, sticky back cork for the bottom. I cut the cork a little smaller than the tiles so it doesn't show from the top.
After attaching the cork to the tiles, it was time to fix the drawings to the front. I brushed a nice, even coat of Mod Podge adhesive to the front of the tile, and carefully laid the drawing on top. With a large, flat paintbrush, I smoothed down the paintings from the middle outwards to set it in place, and then I put a clean sheet of paper over the top of it and used the brayer to really glue it down. After the paintings had some time to dry on the coasters, I brushed another coat of Mod Podge over the top to seal it. You have to be careful here, because some of the ink smeared. I used black Chinese ink, which was pretty waterproof. I also used Chinese watercolors for the colored parts, which was not so waterproof, and I got a little bit of smearing. I had to be extra careful not to brush over and over, and cause more damage. Once that layer had dried, I painted one more layer over the top with no fear of any more smearing. I left them to dry over night, and then sprayed them with one more layer of a clear, waterproof varnish. And voila! Nice, new coasters.