Synopsis: Sealers and their use are a source of confusion to many woodworkers, but they needn’t be. In truth, the first coat of any finish will act as a sealer, penetrating the wood fibers and leaving a rough surface for subsequent coats to bond to. But clear finishes vary in how effective they are as sealers, and products sold as “sanding sealers” often are not the best solution, either. Read on to find out when to seal, what products work best with what finishes, special products for special uses, and why often your best choice can be summed up in one word: shellac.

One aspect of finishing that causes great confusion is sealers and their use. Part of the problem stems from thinking that sealers are to clear coats what primer is to paint and that all bare wood should be sealed first. In fact, the first coat of…