Gluing Bourbon Barrel Coaster Blanks

Select bad or incomplete barrel bourbon barrel top,  don't use ones with the metal pins.  Make sure that when they get glued together they are larger larger than the template.  Use plenty of glue.  If there are dowels, make sure they are glued on both ends as well.

Make sure things are closed together as much as possible before clamping.

Clamp up with the charred side up.  After you've clamped the parts tight together, check for flatness and wipe off excess glue that squeezed out on the top.  Leave it clamped up for six hours.  Ideally this means you can glue up a set of six in the morning, then another six before leaving for the day.