At last fall’s Segmented Woodturning Symposium, I had a discussion with Joe Schlawin. He suggested that acrylic plastic could be used to waterproof certain woodturnings. I needed to know how a solid sheet of acrylic plastic could waterproof the inside of a vase.
It turns out that acetone can dissolve acrylic. It takes some time but acetone can dissolve the plastic.
For this project, I broke up some acrylic into small pieces with pliers. I had to wear my full face shield. The pieces tended to shatter a fly away including at my face. I put about 3/4 inch of small pieces in a pint glass jar with a metal lid. Over the next two weeks, I stirred the mixture and added more acetone. I was amazed when the acrylic changed to a thick syrup. I added more acetone to thin it down.
For the test, I hollowed four cups from cedar. Two of them, I painted the inside only with the syrupy acrylic. It dried hard within a couple of hours – I did not constantly watch them. After drying, I did not detect an unusual odor other than the cedar scent.
Each cup was filled with water and a few drops of red food color. Within minutes, the uncoated cups leaked. One coated cup showed no color on the outside. One coated cup showed color but I think that come over the lip when I moved it.
I have yet to test this process on the outside of a project. But I like what it did so far to the inside.