Flattening the Barrel
The barrel may have been cut in a way that is not completely flat. We use a two foot square piece of melamine as the standard to test against. At first the barrel is placed on the melamine so that the staves can be pounded down with a rubber mallet, thus ensuring the bottom is flat to begin with. Then the melamine is placed on top of the barrel and we look to see if any air gaps are present. If so, we mark the high points and use the belt sander to flatten them out. This is a trial-and-error process and we repeat until pressing on the melamine does not rock in any direction. Notice in the photo that when belt sanding, the barrel is on the melamine itself to maintain the flatness of the bottom.