Yellow. The Klingspor customer magazine - Edition 2|2020

8
GRIT SIZE SEQUENCE
Yellow. The Klingspor Customer Magazine 2|2020
Grinding tips for
professionals
Part 8:
Grit size
sequence
For more info, visit
www.klingspor.de
What is the correct grit size sequence to follow when sanding wood with a
random orbital sander? Our expert, Marcin Grzesiak, explains how to sand wood
with exceptional fineness and precision.
Following the correct grit size
sequence ensures that scratches
resulting from sanding with a coarser
grit are removed reliably. This is of
particular importance when you sand
against the grain, as the resulting
scratches are difficult to remove if the
jumps in grit size are too large. The correct
sequence will save you any nasty surprises
during staining. The problem during the
sanding process: skipping too many steps
in the grit sequence may keep a fine grit
from removing scratches that may have
been caused by a coarser grit.
Therefore, the dependable removal of
scratches from the wood surface requires
that you never skip more than one grit size
in the grit sequence.
A good example of the correct practice
could be accomplished by preparing a
wooden surface with the grit sequence
P80, P120, and P180.
If you follow a P80 grit directly with a
P180 grit, you may still be able to produce
a flat and beautiful surface. You will just
have to invest more time and effort.
However, you cannot be certain of a
particular result until the stain has been
applied on the surface. If the scratches are
still visible following this application, the
workpiece will need to be sanded and
stained again. ■
Advice from the expert
If you wish to ensure that all scratches are
removed, you should refrain from skipping more
than one grit size in your work steps.
The test parameters we apply
Type of wood:
Pine
Machine used:
DeWalt random orbital sander
Product diameter:
150 mm
Abrasives used:
PS33K self-fastening discs
Hole pattern: GLS 3
Grit sequence:
P80, P120, P180
The surface after being sanded with different grits. The surface appears to be scratch-free.
Your professional partner
The image illustrates: the swirl marks caused by sanding with a coarser grit could not be
removed entirely in the subsequent work steps (due to too many skipped sizes in the grit
sequence) and reappeared following the staining of the surface.