TOOLINGAROUND
Abrasive Personality
Abrasive products and machines are essential
to every facet of luthiery, from wood sanding
to finish rubout. This two-part column will give
you a rundown on the abrasives used in the
JET Guitars shop, and valuable advice about
using them. As you will see, all of the abrasive
products are cycled through two or more “life
stages” to get the most out of them before
throwing them away. The basic tools used with
them are a 48” x 6” belt sander, a 1/4 sheet
electric random-orbit palm sander, a variety of
sanding blocks and a 5” PSA air sander.
The belt sander is used for thickness sanding
and rough shaping work. I use 60 and 100
grit aluminum oxide belts – I’m not too picky
about the brand – with 150 and 180 grit for
medium sanding. A Teflon platen is a good
feature to reduce friction, and when it starts
cupping, you can true it flat again or replace it.
You might want to wrap the drums with friction
tape – used on baseball bats – to eliminate the
annoying drop-off from the platen. Another
feature to look for is a quick-change lever. You
will most likely need to adjust it so it works
right, and maybe modify the arm to keep it out
of the way. The most essential component of a
machine like this is the quality of the bearings.
Unfortunately it’s hard to know how good they
are until years later when they start to squeal
and wobble. Sanding belts can be recycled
into metal work, or cut up for hand sanding
after they start wearing out.
The electric palm sander, loaded with 180 and
220 grit AO, is for fine sanding of maple. I
also use it to sand out the first stain wash on a
figured top (for deep grain enhancement) and
I work the tool pretty hard for that task. Using
a lot of pressure goes against most recommendations for sanders like this, but hey, I’m a bad
boy – and it works. You can deal with carved
top re-curves by changing the stock pad with a
thicker one that has rounder sides (see photo).
Naturally, that is something you will never find
for sale, so you will have to fabricate or modify
one. Some luthiers like to use a disc sander on
carved tops.
Selecting a random-orbit sander can be tricky,
and you will go through more than one, but
from my experience, here are the weak features to avoid when picking one out:
• Insufficient power
• Flimsy plastic internal support pylons that
can break
• Wimpy paper fasteners that slip, break or
are hard to use
• A sliding on/off switch, or one mounted on
the sander’s handle
This last item will drive you crazy the first time
the sander unintentionally turns off as you
change your grip.
Always remember that the pad on this sander
is not very firm. Fingerboards and headstock
faces – especially with inlays – often require
at least some precision hand sanding and a
palm sander can distort their shape. Also, don’t
use this tool on softer, plain-grained woods
such as korina or alder as it leaves swirl marks
that appear after staining. Instead, use a belt
sander, and then hand sand with the grain
using a block.
Used 180 and 220 grit quarter sheets get a
second chance when it’s time to hand sand
corners and roundover areas. Don’t throw
them away yet! When they’re so beat up you
think they can’t be good for anything else,
keep a stack around for roughing clearcoats
between spray coats.
In part two we’ll look at sanding blocks and
air sanders.
Jeffrey Earle T.
Jeffrey Earle T. handbuilds JET Guitars in North Carolina,
USA. jetguitars.com
