Epoxy Coating a Fretless Bass

In the early 1970s, Jaco Pastorius took the electric bass world by storm with his signature fretless sound of the Fender Jazz Bass – and people have been chasing this sound for decades. Part of his unique bass tone came from a coating of Pettit Poly-Poxy (Boat-Epoxy) that he applied to the fingerboard to protect it from damage from all-round strings. It also turned out to improve sustain and produce a brighter, crisper tone. Since then, this finishing method has been popular with fretless players and has evolved and evolved over time.

Nowadays, two-part epoxy is popular because of the hardness of the material it cures and because it is wonderful for polishing. Sometimes we are asked to deep-cast epoxy on a fretless bass fingerboard, which we do with the help of our plek machine. Not only does this provide the durability and tone desired by the player, it also ensures that the instrument plays perfectly and that all the notes on the neck speak clearly and evenly when everything is done. There are many ways that people approach this type of work and many ways to get great results, so I’m going to show you the techniques that I think have worked for me. Here we go!

The factory surface of a lined Fretless Fender Custom Shop Jazz Bass.

First, I use the plek machine to level the fingerboard. This way I can get a perfectly even epoxy coating.

We do our fretwork with a spare body for easy access to the truss rod on heel-adjustable, bolt-on necks.

Once I’ve evened out the tiny CNC machining marks, I sand the rosewood onto a 400-grain surface before applying the first coat of sealer. I then build a packing tape dam around the fingerboard.

I use clear packing tape because the adhesive side has practically no texture and the epoxy is easier to work with later.

We like System Three Mirrorcoat two part epoxy. It hardens as glass and is crystal clear and has a nice, long open time. The mixing ratio for this stuff is 2: 1 resin to hardener. This needs to be precise for best results.

After pouring the epoxy pool, I run the drill press to vibrate the table and hit the pool with a heat gun to force any air bubbles to the surface. If you are using duct tape for this, be careful not to melt it with the heat gun. It is best to keep the gun moving.

Once the surface is level and free of bubbles, I let it cure for several days before peeling off the tape.

I do the bulk material removal on the edge grinder to cut a radius back into the playing surface before I put it back into the pick for the final covering.