*Why Isn't the Salad Bowl Oil I Applied to Walnut Serving Boards Drying After Two Coats?

Some pieces of wood contain a lot of oil and walnut can be finicky.

The oil in the walnut wood may be causing the problem you've described - a longer dry time might have been needed over an oily wood. If the wood does not dry over the next few days then it may be necessary to sand down and start over.

Unfortunately, if the first coat does not dry, the second will never dry.