Transcript LIWC Sanding Workshop

SANDING IS BORING



Tedious
Stupid
Not necessary
Why sanding
What is sanding – Materials & Techniques
Protection – Woods
Real Life: Mahogany species and woods from Cameroon: by Gisele.
Introducing Mc Simmons: LIW Resident Expert on Wood Finishing
So boring that the choice of tools is
bewildering
The results are calling upon our senses
Touch
Touch
Touch
Feel
Feel
Hear
Screech
Sing
Look
Admire
Sand or Scrape?


Contrary to their names,
card scrapers, cabinet
scrapers and scraper blades
don’t scratch: they cut
Card scrapers are ideal for
lightly cleaning up areas of
torn or gnarly wood that no
other tool can deal with, but
sharpening it is a task that
frustrates even experienced
woodworkers
Why - technically




Shaping then Smoothing
If grain changing direction: easier to sand than
to use an edge tool ( planer )
“Fill” – Equalize
Finish the finish
Grain

Emery - An abrasive that is a natural composite of Corundum and Iron Oxide. The grains are
blocky, cut slowly, and tend to polish the material being abraded.

Aluminum Oxide - A blocky, hard grain best suited for sanding and grinding of ferrous and nonferrous metals, wood and solid surface materials.

Garnet- A very sharp grain that cuts very quickly when new. Fractures quickly, keeping it sharp.
Perfect for sanding wood end grains or for final-finish sanding of wood. Very economical.

Stearate - An additive that prevents loading when sanding soft resinous woods, after sealer coats
and when working with soft ferrous or non-ferrous metals. Not an abrasive grain.

Alumina Zirconia - A very hard and sharp grain that works well for grinding of stainless steel,
spring steel, titanium and other hard steels and for dimensioning of wood.

Crocus -A natural abrasive of iron oxide particles. Used mostly for cleaning and polishing soft
metals

Silicon Carbide - A sharp, very hard and brittle grain best suited for sanding of glass, plastics,
rubber, ceramics, solid surface materials and some non-ferrous metals.
Backing
Paper
A - A very light weight paper - typically for sheet use only or light PSA or hook &
loop disc usage
B - A light weight paper - typically for sheet use only or light PSA or hook & loop
disc usage
C - A medium weight paper - typically for sheet use only or light PSA or hook &
loop disc usage
D - A medium to heavy weight paper - typically for sheet use only or PSA or hook
& loop disc usage
E - A heavy weight paper - typically for stroke or wide belt sanding
F - A very heavy weight paper - typically for stroke or wide belt sanding



Cloth
J - A light weight, flexible Egyptian cotton cloth
JF - A light weight, very flexible Egyptian cotton cloth
X - A heavy, stiff Egyptian cotton cloth
XF - A heavy, yet flexible Egyptian cotton cloth
YX - A lighter weight polyester backing
YY - A very heavy, stiff polyester backing



Fiber –
A very hard, strong, coated abrasive backing material consisting of multiple plies of
chemically-impregnated paper. Used primarily for disc products.


Names
Sanding Sequence







Start to plane
What about a card scraper? No Edge tool after sanding !
Remove all scratches from previous operation => Vacuum /
Dust off / Blow off with air. Run your hand over the surface your fingers and palm are remarkably sensitive. Vacuum and
wipe with a lint-free cloth.
Remove any grit from the previous sanding. I doesn't become
apparent until you stain. Wiping with mineral spirits or lacquer
thinner
The Pencil Mark Depth Gauge
On a drawer, sand all pieces BEFORE assembly
Save Time and Sweat: 4 minutes per sheet / Throw away
before it glazes – before it gets dull
Storage



Store in dry, frost free conditions. Away from
heat sources, cold, damp walls, doors or
windows and should not be in direct contact
with the floor.
Temperatures and humdity should be between
18-22 °C and 45%-65% Relative Humidity.
Keep products in their original packaging
Filing system
Grit sequence



Milling mark: use 100 grit
Vacuum – Don’t skip 120, 150
Sand the whole piece, everywhere!







Most finishes “like” 220
Penetrating oil: 400
Water based glazes: 150 ( water will raise the grain
anyway ) then 180 through 400
Use finer grit ( 100) on more aggressive tools ( belt
sanders) : there is more sanding surface on a 100 grit
than on a 80 – it will bite more!
The harder the wood, the harder it is to remove
scratches
Let the tool do the work: guidance – not pressure
Always use a sanding block
Use a mechanical sander
Final pass with your finest grit using very light
pressure on the orbital sander.


Lift the sander straight up and not tilt it.

Keep the sander at full speed while sanding.

Start with 120 for grinding of glue and joint leveling.

Going from 100 to 150 is a no-no.
You can't skip grits on a stained project. OK on paint. Most veneered plywood is
already sanded to 150, but it is a straight sanding as opposed to orbital, so you need to
get rid of the straight scratches. Use 150 on pre-sanded veneers.

A finish sander has a smaller swirl pattern (3/32")
while a normal sander has a larger pattern (3/16").

Cut a sheet
Crease – torn only along half its length
First quarter is folded – grit facing out
Two thicknesses are folded on sheet’s third quarter smooth
surface
Fourth quarter is folded onto final shape
Cut a sheet with a jig
Mark the back!
Hand Power Sanding Systems





Edge tools – Planer - Scraper
Not to Be Found:Stanley Rasps
Sand a Profile
Wipe, Blow, Lift, Dust off
Water / Alcohol / Spirit
Motorized Sanding Systems




Disks Rasps – Disks Coarse – Disks Flaps
Large Rectangular Sanders
Porter Cable Random Orbital Sanders
Profile Sanders: Roybi, P.C., Fein
Sharpening the Scraper





Get rid of harden metal from the burnishing
tool and flatten edge on a rasp with a coarse
mill file
Flatten the edge with a file
Smooth edge with a stone
Burr / rotate and flip the burr
Listen to the whistle blowing in the wind