Trade Secrets!

Dan Erlewine's Facebook fretless bass

Issue 139 May 12, 2011

I’ve been having fun posting shop shots on our StewMac Facebook page, and that led to something new: you can go see big versions of these photos on Facebook!
Dan Erlewine, May 12, 2011
Photo: Dan Erlewine
My friend Adam had two P-style basses, one pretty much like the other. To give him some variety I converted this one to fretless, removing the frets and filling their slots. The result is a fretless bass with fret lines that help Adam play in tune — like a bicycle with training wheels!
I started by clamping the neck on blocks and pulling the peghead down to create a backbow (photo above). This opened the fret slots slightly, so my fret puller could coax the frets out without chipping the slots.
Photo: pulling frets
Thanks to the backbow, the frets came out easily. I had a soldering iron ready to heat the frets and soften the glue under them, but I didn’t need it.
Photo: feeler gauge
After unclamping the neck, a .024" feeler gauge fit snugly in the slots. And the binding I wanted to fit in there was .040" thick.
Fret Puller

Feeler Gauges
Photo: routing the fret slot
So I widened the slots with a .031" diameter Dremel bit. The final result was a bit wider than the cutter bit: between .034" and .035".
Photo: scraping the binding
I used a scraper to thin the binding a little, removing about .003". That still left it a bit wider than the slots, which is what I wanted.
Precision Router Base

Scraper Blades

Photo: trimming the binding
The binding was 3/8" tall — wide enough to provide two usable strips when nipped in half lengthwise.
Photo: installing binding strips
I tapped the strips into the slots with my rough-cut edge up. The plastic bent to conform with the curve of the fretboard (a 14" radius).
Fret Cutter

Black Plastic Binding

Photo: gluing the strips
I ran water-thin super glue along both sides of each “fret,” letting it seep into the slots. I let it dry for 15 minutes.
Photo: radius sanding
The excess plastic came off with a 14" radius block and 80-grit sandpaper. I stopped just shy of the surface to avoid scratches, and followed with 120, 220 and 320-grit papers until the plastic was smooth and flush with the fretboard surface.
Super Glue

Wooden Radius-sanding Blocks

With the truss rod adjusting nut barely snug (applying hardly any tension to the neck), I checked the fretboard with a precision straightedge. The playing surface was perfectly straight from end to end, with a uniform 14" radius.
The real test would be stringing the neck to pitch and seeing if it could be adjusted straight under tension:
It did! I lucked out!
After cleaning the board with naphtha, it's ready for a clear finish. I used super glue as my finish; it’s clear and tough.
Photo: checking the fingerboard surface OptiVISOR

Precision Straightedge

Photo: super glue for finishing
I wiped the glue on with wet-or-dry sandpaper. (I don’t need to tell you it’s important to wear gloves, right!?)
You can see where I missed a spot. That's OK, I wiped on lots of coats, and caught this on the next one.
Photo: partial super glue finish
Photo: Dan sanding outdoors
The weather was great, so I avoided the super glue fumes by working outside. I used #20 medium glue, sometimes mixing in some #10 thin to make it wetter and easier to apply.
Photo: accelerator
The coats dried fast: in five or ten minutes I could spray accelerator on the back of clean sandpaper and wipe the board with that — drying the finish completely.
After 3 or 4 coats, I started lightly sanding between coats with 320-grit gold Fre-Cut sandpaper. After a few more coats I switched to 400, then 600, then 800-grit using a rubber sanding block.

3M Gold Fre-Cut Sandpaper

Photo: wet sanding
It started to rain, and I went indoors. (Which is sort of funny, since my next step was wet-sanding!) I wet-sanded with water and ever-finer grits up to 2000-grit micro-finishing paper, then followed with Micro-Mesh pads from 3200 to 12,000. After that I hand-buffed it with a soft rag and medium paste polishing compound.
And here’s the result: Adam’s using it in his recording studio. He says it’s like having a whole new bass!
Micro-Mesh Soft Touch Finishing Pads
Photo: finished fretless bass

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