My last three columns have featured Guzzlers, a well-worn 1997 Musicmaster bass from Fender’s Squier Vista Series. Guzzlers’ hard-to-adjust neck is straight, his once-rusty hardware and dirty electronics are clean, and two broken potentiometer shafts are fixed. Now, before Guzzlers loses patience and puts himself back together, it’s time to shield the control cavity with copper foil to reduce interference and improve the single-coil pickup’s sound. Fig.1 To install copper foil in a control cavity, press the foil against the cavity’s edge, rubbing along the edge to make an imprint. Next, cut along the imprint with either scissors or a hobby knife. Use separate pieces of foil for the cavity’s sides and bottom, overlapping the edges where they meet to create a good seal. Fig.2 Make sure that the pickup works by testing it with a multi-meter set to 20k on the ohms scale; that’s the range of the scale used to measure passive electric bass and guitar pickups. This one measures 63kΩ—that’s a strong single-coil pickup! Fig.3 Be sure to re-install the ground wire that contacts the underside of the bridge to ground the strings. Fig.4 To minimize single-coil pickup hum, shield the body cavity and the perimeter of the pickup on the underside of the pickguard. Fender glues a thin aluminum shield to the underside of the pickguard, which helps reduce hum, but shielding the entire cavity produces even better results. Fold the copper foil over the cavity edge and onto the instrument’s face, to make contact with any shielding on the pickguard’s underside. Fig.5 If the fretboard is dirty, use 0000-grade steel wool to clean the dirt built up along the edges of each fret and on the fretboard. Use cross-grain strokes along the fret edges, and then follow with the wood grain on the fretboard. I prefer Liberon brand steel wool; it’s a finer grade than what you’ll find at the hardware store, and it isn’t impregnated with oil like most steel wools. Fig.6 To keep steel-wool dust to a minimum (or to “vacuum” it up), I wrap the steel wool around a w" magnet. Never hold a magnet closer than six inches from a pickup—you could permanently alter the pickup’s magnetic characteristics, and therefore, its sound. Fig.7 After cleaning a dirty fretboard, you might find that the wood underneath is dry. You can rejuvenate the wood with a number of fretboard-finishing products. I prefer those with linseed oil as an ingredient. One small rag dipped in finishing oil, blotted slightly dry with a paper towel, is often enough to work over the entire fretboard. Let the oil penetrate the wood for three or four minutes; then remove the excess with a clean rag or paper towel. Dispose of the oily rags (and used steel wool) outside—they are combustible! Fig.8 Kinked strings are difficult to intonate, so you’ll want to keep them from kinking in front of the exact
	—Dan Erlewine works on new product design and is the staff writer for Stewart-Mac-Donald’s Guitar Shop Supply in Athens, Ohio. Dan still builds and repairs basses and guitars in his home shop. His monthly repair column Repairs & Modifications, and numerous feature articles, appeared in Guitar Player for 16 years. His books, Guitar Player Repair Guide (1990) and How to Make Your Electric Guitar Play Great (2001), are published by Backbeat Books.
	Orginally published in BASS PLAYER magazine. Copyright © 2006 CMP Entertainment Media. All rights reserved. Used by permission.