Waterborne Solutions

by Mike Doolin and John Greven

from their 2001 GAL Convention demonstration

Originally published in American Lutherie #73, 2003



Doolin: Waterborne finishes and methods of working with them are constantly evolving. New products come out every year and old formulas are continually being updated. This workshop is like a snapshot of what John and I were doing at the time, and our techniques have continued to evolve. We trade techniques back and forth and share our results with new products as they become available. We never seem to be using exactly the same products or techniques; this just goes to show that there is no perfect finish product or technique yet. However, John and I agree that the products which have become available in the last few years are finally up to the task of producing a finish worthy of a fine handmade guitar.

Before we get into the nitty-gritty, I want to talk about what waterborne finish is. First, think of lacquer and shellac. Both lacquer and shellac are resins dissolved in solvent. Spray it on, the solvents evaporate out, and that’s it. There’s no structural cross-linking reaction going on. Anytime after the finish is dry, you can use lacquer thinner to wipe the lacquer off the guitar. The same is true for pure shellac, which is always soluble in alcohol. That’s useful for a finish which will be rubbed out, particularly if you’re going to be touching up at a later time. You can melt that coat in. Otherwise, if the subsequent coat has to stick by a mechanical bond, you get a witness line if you sand through the top coat. One of the advantages of the new waterborne finishes is that they seem to do that — to burn into their previous coats. That’s one of the things we’re looking for.