Tuesday, 24 January 2012

Carl Thompson Restoration

Now and then, I get the chance to work on a unique instrument from a well respected luthier. Carl Thompson's bass designs always interested me, and this year I had an opportunity to restore a 4-string made in 2004.

The bass had spent years in humid Queensland, resulting in shrinking and slippage of the glue seams and joints. The customer also suspected truss rod issues, as they were having trouble with relief stability (thankfully, this wasn't the case!).

This bass required a re-fret (as the original frets had been removed and replaced with hardwood veneer), restoration of shifting glue seams and laminates, and a full setup, including nut filing.

First, all hardware was removed and bagged. You can see Carl's signature on the control cavity.

The walnut laminate here was separating from the mahogany centre block.

The tapered headstock laminate glue seam was shifting where it joined the neck, and formed a gap.

It's tricky to see, but the walnut laminate stripe also shifted due to glue slippage.

The accent timber (cat's eyes) on the wings had suffered the worst from the climate.

Some copper shielding had to be replaced due to deterioration.

The original oil finish definitely needed restoration to get back to a low-gloss "glow"

Before beginning the re-fretting, several layers of strong tape were used to protect the top and horns.

A fret-slot depth gauge is critical for making sure the new frets have enough depth for the tang. Also, re-sawing these slots was one of the toughest jobs my fret saws ever tackled. It was blister city!

Once the board was re-slotted, fretting began.

All frets installed.

Bevelling the fret ends, and cleaning up the tangs.

Taped off and ready for levelling.

Rough crowning.

Fretwork is complete. Now on to repairing the finish.

Here's the result of a lot of sanding, hand rubbed oil and wax.

Here's the repaired and re-finished cat's eye.

The top finished beautifully, bringing out the detail in the grain.

Shiny new frets, shiny new finish.

The headstock, restored and re-badged.

Re-strung, set-up and good to go.


This was a very satisfying repair, and it was a privilege to restore. This bass is light, fast and very responsive to attack. The truss rod behaved perfectly, and the relief was very controllable (even with the extra long 36" scale).

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