The other night, while browsing Instructables, I came across this one by Tom Howbridge:
After glancing at my drink sweating on top of a newspaper, I thought I would give his idea a try. I used slightly different materials and processes than Tom, so check it out!
Step 1: Material
I used 1/4" Baltic birch to make the coasters only because that is what I had laying around. Thicker plywood would have made the glue up a little quicker.
I cut 16, 1" wide x 16" long strips.
Step 2: Glue Up
Lay the strips out so that they are tight together. Spread a liberal amount of glue on the surface and spread it around with a scraper. Make sure all the surfaces are covered. This is the fastest way I have found to cover a large surface.
Step 3: Clamp It
Stack the strips on top of each other. Flip the final strip so that it's glued side is facing in. Carefully clamp. Keep the glue up as even as possible, it will make it a lot easier to sand later.
Step 4: Resaw
It's way easier to glue and clamp a 1" strip than a 1/2" strip, so I started thick, and now am going to resaw to the finished thickness (minus sanding.)
Step 5: Sand, Cut, Sand
Sand both faces of the coaster blanks. I am lucky to have a drum sander to speed things up, but it could certainly be done with a belt/palm sander.
The edges were sanded on the belt sander.
I only sanded down to 80 grit on this one. The wood is very soft, it looked pretty good at 80, plus these coasters will probably be abused and I'm not sure what their lifespan is going to be, so I didn't want to go nuts sanding them.
Step 6: Finish
Start by vacuuming the coasters with a brush to remove any dust. An old timer told me to vacuum rather than use the air compressor because compressed air will push the dust further into the pores of the wood, whereas the vacuum will pull it out of the pores.
In order to make this project as quick and painless as possible, I finished the coasters with a spray coat of polyurethane.
Step 7: Enjoy
The finished coaster is about 3/8" thick. Its a fun, near zero cost project to burn up some scrap plywood!