Surface cleaning with abrasives
he first prospecting
technique to be used on suedes before drycleaning or
wetcleaning is surface cleaning or abrasive spotting. This
technique uses one or more of the following abrasive spotting
tools:
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• The abrasive block.
• The steel wool pad.
• The sand blaster.
Caution: never use any of those abrasive
spotting tools on leather! Use only on suedes!
Surface cleaning with the abrasive strip
The first tool for abrasive spotting we
will consider is the abrasive strip. It is a medium grit
carbide emery cloth that comes in rolls or sheets. Rolls are
easier to work with since they don’t have to be cut up
into strips to make usable pieces.
The pieces of abrasive needed can easily
be torn off of the end of the roll by hand. The emery material
with its cloth backing is far more durable than sandpaper. The
medium grit will normally allow good soil removal with minimum
risk of damage to the suede.
The piece of abrasive strip can be used on
any suede at the spotting board or spotting table to scrape off
any crusty spots, stains, soil, oxidation marks or ink marks
that are found on the surface of the suede. Surface crusty
spots include soil, food, blood, ink, paint, nail polish and
glue on the surface of the suede.
The abrasive strip may be gripped between
the thumb and the forefinger and pressure may be exerted on the
cloth side of the strip by either the thumb or the forefinger
or the forefinger and middle finger together.
The amount of pressure applied should vary
with the type of skin being spotted. Use light pressure for
lambskin and sheepskin suede. Use heavy pressure for cowhide
and pigskin suede.
The abrasive side of the strip is placed
in contact with the surface of the suede wherever there is a
crusty surface stain spot or ink mark.
The abrasive strip is rapidly drawn across
the spot several times from every direction until the crust of
the spot or ink mark is scraped off. Scrape less on lambskin
and sheepskin suede. Scrape more on cowhide and pigskin suede.
Some of the suede nap may be removed by
this process. This will not be a problem as there is plenty of
nap and it will not be missed. The area scraped may look
lighter in color after the rusty spot, stain, soil, oxidation
or ink mark is scraped off. This is not a problem. The light
color will disappear in the cleaning or after cleaning by hand
spraying the suede with a neutral spray like Royaltone’s
Suede Nu. There is no need for expensive spray kits or air
brushes or propellent cans to do this refinishing or any other
refinishing on suedes or leathers.
Care should always be exercised when using
the abrasive strip on soft, delicate or weak skins to avoid
damaging the surface. A residue of stain left in the skin after
the surface crust has been abraded and removed is an indication
that the staining material has also soaked into the skin in
addition to leaving the residual surface crust or ink mark. In
such cases, the residual spots or stains will have to be
spotted with the appropriate Spot Wiz liquid spotters after the
abrasive spotting is completed.
The best way to prevent liquids from
soaking into suede or leather is to pretreat the skin with the
special Royal Shield suede and leather liquid repellent
protective coating that resists penetration of liquids into the
skin but does not change the color or feel of the suede or
leather. Do not use repellent made for cloth as it is likely to
make the color darker and cause the skin to become stiff and
the nap to become coarse and matted.
Once the protective coating is
applied to a suede or leather, any liquids that spill on the
suede or leather item remain on the surface instead of soaking
into the skin. The liquids can be blotted up from the surface.
Any residues that remain will be surface residues that will
clean off or will brush or scrape off the surface with the
abrasive strip. No residue of the spot will remain.
Surface cleaning with the abrasive block
The abrasive block is a spotting tool that
can be used to surface clean and rapidly remove crusty spots,
stains, soil, oxidation and ink marks from cowhide and pigskin
suedes only and not on delicate sheepskin or lambskin suedes.
This abrasive tool has the advantage of
rapidly removing crusty spot and stains. However, it is always
used only on cowhide and pigskin suedes as they are the only
skins that are tough enough to withstand the highly abrasive
action of the abrasive block.
Caution: never use the abrasive block on
any smooth leather. It is for use on tough cowhide and pigskin
suedes only!
The abrasive block is very abrasive,
porous inconsistency and very hard with sharp edges. Sometimes
called lava rock, volcanic rock, stink stone‚ or pilling
stone‚ it is black in color. It is man-made, formed into
blocks of various sizes that can readily be hand-held to scrape
the surface of cowhide and pigskin suedes at the spotting board
or spotting table.
The abrasive block resembles volcanic rock
and lava rock. It also releases a sulfur odor of rotten eggs
when used in a way that wears it down and exposes its inner
structure. This occurs when excessive physical pressure is
exerted on the block as it is scraped across the crusty spot on
the surface of the cowhide or pigskin suede. Hence the names
lava rock‚ volcanic rock‚ and stink stone. This
type of black abrasive block is also used to remove pills from
sweaters. In this application, it is called a pilling stone.
To use the abrasive block, grasp it firmly
with the thumb and forefinger. Rub the end of the block across
the crusty surface spot or stain in all directions while
applying pressure on the block with the palm of the hand.
The pressure can be varied to suit the
spot being removed. On most cowhides and pigskins there is no
limit on how much pressure can be applied, but excessive
pressure will cause disintegration of the block at the point of
contact with the skin.
When that happens you will know that you
have used too much pressure. Too much pressure will only damage
the abrasive block and leave a gritty residue. It will not
normally damage a healthy cowhide or pigskin suede.
As in all things, use common sense. There
are some cowhide and pigskin suedes that contain panels that
come from unhealthy animals and from belly skins. These skins
may be weak and thin with a ragged nap. Use the abrasive block
and the abrasive strip on these skins with care and with light
pressure to avoid damage.
On healthy cowhide and pigskin suedes, the
abrasive block will remove some of the suede nap from the skin
surface along with the crusty spot or stain material. This is
not a problem. Most of the nap will remain unless excessive or
unnecessary abrasion is done in a local area.
Pigskin suedes have a very short nap and
will not lose as much suede nap when a crusty spot or stain is
abraded. However, even with a pigskin, avoid excessive and
unnecessary abrasion when surface cleaning.
Remember, you are trying to remove only
the surface of the crusty spots and stains, not the residue of
the stain that has soaked down into the skin. To attempt to
remove the residue of the stain by abrasion will eventually
make a hole in the skin.
For the residue of the stain that remains
in the skin after surface cleaning with the abrasives, remove
it in drycleaning by using safe liquid stain removers like
Royaltone’s Spot Wiz liquid spot removers and Soil Go
soil release or in wetcleaning with safe liquid stain removers
like Leather Magic liquid prespotter, Spot Magic POG Spotter
and Ink Magic ink spotter.
Surface cleaning with the steel wool pad
Another abrasive spotting tool that may be
used to surface clean suedes to remove crusty spots, stains and
ink marks is the steel wool pad. This abrasive tool has the
advantage of being less abrasive and less likely to cut into
the surface of the skin.
The pad also has the disadvantage of
leaving a lot of steel wool shavings all over the suede on
which it is used. These steel shavings can oxidize and rust if
left on the surface of the suede after it is spotted with a wet
side prespotter.
In addition, the person using the steel
wool pad can get steel splinters in his or her fingers. Steel
wool shavings accumulate around and on the spotting board and
require frequent clean-up. The steel wool shavings can also get
into the cleaning machine, its pump and its filters. These
shavings are the result of the breakdown of the steel strands
in the steel wool pad. Since the pad breaks down rather
rapidly, the quantity of pads used can be significant.
The steel wool pad is used in much the
same way as the abrasive strip and the abrasive block
previously described. The steel wool pad is held between the
thumb and the other four fingers. The pad is than drawn across
the surface of the suede several times, from all directions
— first in one, then in another — until the surface
crust and stains are removed.
Some surface suede nap will be removed
along with the stained material. The amount of suede nap
removed will increase with the grade of the steel wool pad. The
coarser the pad, the more nap will be removed when the pad is
rubbed across the suede.
As in the case of the abrasive strip and
the abrasive block, the small amount of nap removed from the
surface of the suede will never be missed.
Steel wool pads come in a variety of
grades from very fine to coarse. The typical grades of steel
wool pads are as follows:
1. Super Fine Grade numbers 0000 and 000. These pads are for an extra-smooth affect on
suedes. This grade is good for removing crusty spots and stains
from very soft and delicate suedes such as lambskin and
doeskin.
2. Very Fine Grade number 00. This pad is used in the same way as grades
0000 and 000, is used on skins that are a little less delicate
such as soft sheepskin and deerskin suedes.
3. Fine Grade number 0. This pad provides a step up in abrasiveness and
can be used on soft calfskin suedes and mature sheepskin
suedes.
4. Medium Grade number 1. This grade may be used to remove crusty
spots and stains from the softer cowhide and pigskin suedes.
5. Medium Coarse Grade number 2. This grade should be used to remove crusty
spots and stains from cowhide and pigskin suedes.
6. Coarse Grade number 3. This grade is used only on mature cowhide
and pigskin suedes that are excessively soiled and badly
stained.
Surface cleaning with the sand blaster
The sand blaster is an abrasive spotting
tool that provides mechanical muscle for high-volume production
surface cleaning. It propels abrasive particles with compressed
air through the nozzle of a gun into the surface being cleaned.
There are several different types of
abrasives commonly used in sand blasting. The use of sand
blasting to remove crusty spots and stains from suedes is an
adaptation of a technique originally developed for cleaning
metal, concrete, brick, plastic and stone, for frosting glass
and for removing surface finishes from wood.
Sand blasting of suedes must be done with
great care by an experienced operator to avoid damaging the
sueded skin. If sand blasting is done by an inexperienced
operator, the suede can quickly have a hole blown through it
where the spot was located. If the operator is
semi-experienced, the suede can be quickly worn down to the
equivalent of five to ten years of normal wearing. If the
operator is experienced, the crusty spot or stain can be
removed quickly and efficiently.
The big drawback to sand blasting is that
some of the abrasive particles cling to the suedes and come
loose in the cleaning machine where they enter the cleaning
fluid pump. There they abrade the pump impeller and cause
unwelcome frequent maintenance to replace pump impellers. In
addition, the abrasive particles enter the pistons of air
operated presses and cut up the o-rings and cup seals. This
creates additional unwanted maintenance.
The investment in equipment required to
perform sand blasting on suedes includes the following: air
compressor; sand blast gun; an air hose and couplings; blast
cabinet; pressure regulator; moisture regulator; proper
sandblasting abrasive; abrasive reclaimer; and a dust
collector.
A suction-type blaster is appropriate for
use on suedes. It delivers only one-fourth the velocity and
impact of the pressure blaster, so it is less likely to damage
the suede in the hands of an experienced operator.
The item being sand blasted is placed
inside a cabinet for operator comfort and efficiency. The work
is illuminated by internal lighting and can be observed through
a safety glass window.
The operator reaches into the cabinet by
inserting both hands and arms through two armholes in the front
of the cabinet. Protective gloves built into the armholes
protect the hands and arms of the operator and prevent any of
the abrasive particles and dust from escaping the confines of
the cabinet through the armholes.
The abrasive reclaimer draws the abrasive
out of the cabinet. Dust and debris from the suede are removed
from the abrasive and are conveyed to the dust collection
system. A removable debris screen traps the suede lint prior to
dropping the reusable abrasive into the storage section. A feed
system measures the amount of abrasive fed to the last gun.
The dust collection unit allows continuous
cleaning of exhausted air by the use of cloth filters. Dust is
collected in a dust drawer.
The abrasive that is most applicable for
suedes is a by-product of agricultural products. These
abrasives are soft, slow cutting and specifically designed for
use on soft surfaces. They include walnut shells, crushed fruit
pits, ground corn cobs, ground rice hulls, etc. For faster
action, manufactured abrasives like aluminum oxide or silicon
carbide can be used. Natural abrasives like sand are no longer
commonly used.
Frank Lucenta is president of Royaltone
Co., Inc., a firm that manufacturers the products he developed
to make it possible for any cleaner to safely and profitably
dryclean, wetclean and finish any suede, leather, fur and
trimmed cloth garment. He also wrote related instruction books
that document the process, entitled “Handling Leather and
Suede” and “Cleaning and Finishing Leather and
Suede.” He also teaches small groups of plant owners and
managers how to identify, accept, spot, dryclean and wetclean,
press and recolor suedes, leathers, and furs using his
Royaltone procedures and products. The next Royaltone Leather
training session is scheduled for April 1-2 and June 10-11 at
the Royaltone Suedemate Leather Cleaning Center in Tulsa, OK.
For more information on training sessions or on spotting charts
in either English or Korean, call (800) 331-5506, (918)
622-6677, fax (918) 665-6017, or e-mail frank@royaltone.com. Information is also available on the Royaltone
web site, www.royaltone.com.
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