Finishes

Christopher Cozad

Senior Member
Platinum Supporting
Gold Supporting
Joined
May 11, 2010
Messages
2,413
Reaction score
1,425
Location
near Charlotte, NC
Just an FYI. I just built a mandolin and used a new type of shellac marketed as Royal Lac...

Good stuff, Br1ck.

A few years back I chatted at length with the developer of the finish, Vijay Velji. I quickly came to appreciate the effort that went into creating an easy-to-apply, shellac-based product that has the warmth, clarity, durability (harder than NitroCellulose Lacquer), and solvent resistance most everyone expects from an instrument finish these days.

Primer: NCL and Shellac are evaporative finishes...after application the solvent (carrier for the solid material(s)) evaporates and you are left with a hardened, dry coating (finish). UL-cured Polyester and Royal Lac are reactive finishes...the solvent evaporates and a chemical process called "cross-linking" bonds the solid material(s) into a coating that is more durable than can be achieved with an evaporative finish.

For the well-cared-for (or "babied") wooden musical instrument, it is hard to beat a traditional (pure shellac) French polish. This finish is known to produce one of the warmest, richest and deepest visual experiences. Though definitely softer (more prone to scratches) than NCL or UL-cured Polyester, and readily dissolved when subjected to solvents (it can typically be repaired as readily), it is much more durable than it is made out to be. The fact that Shellac is nothing more than a resin secreted by the Lac beetle, dissolved in alcohol, and rubbed onto a guitar to whatever depth the finisher desires makes it very appealing to the eco-conscious, chemically sensitive, hand-crafted, etc. crowd(s).

For the rest of the guitars out there (such as those belonging to the gigging musician, or the manic spiller of beer and wine, or even those made by the luthier looking for a low VOC alternative to lacquer), though Shellac may be out of the race, Royal Lac is a legitimate contender. The original formulation could be sprayed on, brushed, padded or even French polished. But the 30-day cure time was a bit of a turn-off to most builders, and Vijay went back to the drawing board. Royal Lac's latest incarnation is a "post-catalyzed" formulation (you add the catalyst to the base prior to usage) that can be buffed out in about a week (or less). It was designed to be sprayed (this is where the product really excels), it can be brushed (technique makes all the difference, here) or padded (Vijay, the developer, prefers padding, using a small brush for hard-to-reach surfaces). Unfortunately, this version of the product cannot be French polished in the traditional manner but, with some patience, you can achieve an acceptable "hand applied" look using a combination of padding and brushing.

My first Seal Lac/Royal Lac (post cat) test project happened to be an old Guild. I was pleased enough with the results to replace my waterborne finishes with the product.
 
Top