Black & Decker FP1610 Manuel d'instructions télécharger pdf (Page 8)

its bright orange color. Even though it is not the hardest, the way the abra-

sive fractures gives you a good cutting edge for woodworking.

Emery, even though harder than garnet (Mohs’ Scale 9), has blunt edges

making it a poor sanding abrasive. Its primary use is for polishing metal.

Manufactured Abrasives

White Aluminum Oxide (AlO) is extremely hard (Mohs’ Scale 12) and durable

which makes it a great abrasive for use with the Random Orbit Sander.

“White” describes the particular way the abrasive is manufactured, not its

color. This abrasive is widely available and comes in a variety of colors due

to the increasing use of dyes. Stearate lubricants on the paper also enhance

performance by reducing heat and the rate at which the paper clogs.

Silicon Carbide (SiC) is the hardest abrasive (Mohs’ Scale 13) commonly

available next to industrial diamond but is not as tough as Aluminum Oxide

abrasives. This abrasive easily fractures and provides sharp faces to the

work throughout the life of the sanding paper. This “self-sharpening” feature

makes SiC an outstanding abrasive for material removal but limits its life.

OPEN COAT VERSUS CLOSED COAT

Abrasives are applied to the paper with glue. When the grit is large (say 60 or

80 grit) the percent of coverage is usually reduced to 60% to 70% of the

backing paper surface.This increases the life of the paper by reducing the

rate at which the paper clogs. This is called an open coat and almost the only

way you can buy sandpaper in heavier grits. With finer grits the grit is

applied at rates of 90% or more and are labeled closed coat. Since the dust

particle is much smaller the tendency of the paper to load up and clog is

greatly reduced.

GRIT SIZES

There are several grading systems used. The system most popular today is

sieve size. The number on the back of your sandpaper disc refers to the screen

size the particle can pass through. 120 grit paper for example will sift through

a screen with 120 holes per linear inch. Every square inch of screen has 14,400

holes (120 x 120). The higher the number the finer the particle size. Common

sizes are from 36 to 600 with the recent introduction of grit sizes up to 1200.

SANDING

THE BASIC RULES: Which ones to break and which ones not to.

Always start with the coarsest grit first. Don’t break this rule. The scratches

get smaller as the grit number gets larger and the quality of the finish gener-

ally improves. When you change grits be particular about cleaning the sur-

face that you are finishing. An 80 grit particle floating on your work under

your 220 grit paper will leave 80 grit scratches. The best way to avoid this is

to vacuum the work and then carefully wipe down the work with a tack rag.

The random orbit sander/polisher action is equally applied across the grain

and with the grain. Since the scratch mark is small and random in all direc-

tions, the ability of the eye to see a scratch is greatly reduced.

Always wear a mask to avoid breathing the dust. NEVER BREAK THIS RULE.

We have engineered the tool to collect a majority of the dust created in the

sanding process but the tool does not capture it all. To improve the capture

rate use a vacuum but ALWAYS wear a dust mask.

SOME OTHER HINTS FOR A BETTER FINISH

A random orbit sander is much more aggressive than other similarly sized

orbital tools so you may want to consider the next finer grit when you start

to sand your project.

Since the random orbit action makes a short scratch, you may find that a

project doesn’t require as many grit steps. A lot of professional cabinet

makers only use 80, 120, and 150 grit on their work with satisfactory

results. If in doubt about how the finish will take to your sanded surface,

wipe the surface with some paint thinner. Defects will show up darker than

the surrounding wood.

Careful inspection of the work prior to the finishing operation may reveal

dents. Try to correct these problems by raising the dent (a hot iron and wet

rag will do this) or carefully sand a large area around the dent. If you vigor-

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Black & Decker FP1610 Manuel d'instructions Page 8

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