STAINS & STAIN REMOVAL
All stone is absorbent, some more
so than others. This is due to the stones physical
properties related to its porosity, permeability and absorption.
| Granite | 0.2 - 0.5 | Slate | 0.1 - 1.7 |
| Marble | 0.2 - 0.6 | Sandstone | 0.2 - 9 |
| Quartzite | 0.1 - 1.4 | Limestone | 0.2 - 12 |
The staining of stone and
masonry surfaces can prove be problematic for a variety
of reasons.
Some spots that look as if they may be a stain are actually etches or a hazing
or dulling of a highly polish surface. Marble, limestone
and travertine are typical
stones affected by these situations. These types of
situations may also be a
combination of a etch and a staining substance or a
prolonged soiling of the etch
causing it to appear as a stain.
The minerals in stone have a definite chemical composition, because of this in some
situations certain chemical reactions can take place
between a part of the chemical
composition and the staining substance producing a
permanent stain to occur.
Some plant fertilizers can cause permanent chemical
reactions to occur.
Some stones have moisture sensitive minerals and substances that can cause the stone
to develop stains.
The ingredients in some stain removal compounds can cause a slight irreversible
bleaching effect to dark colored marbles and limestone's.
Using the wrong chemical can carry the stain deeper into the stone or set the stain
making it permanent.
Old or deep-seated stains may not be fully removed leaving a slight shadow or they
may not be removed at all.
A
hazing, dulling or etching of a polished finish may occur.
The longer a stain remains it migrates deeper into the fabric of the stone and becomes
more permanent.
IDENTIFYING
THE STAIN
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Stains have been classified in a few ways...Organic
and inorganic, water-based, oil-based
and have been fitted into five categories...
Organic : Food, fruits, coffee, tea, beverages, cosmetics and tobacco.
Oil Base : Greasy foods, cooking oils, grease, tar, skin and hair oils.
Inks / Dyes :
Felt tip markers, pens, natural and synthetic dyes.
Biological : Vegetation, mold, mildew, algae, fungus, etc.
Metallic : Iron (rust), copper, bronze, etc.
It is important to try to properly identify the source of the stain for a couple of reasons.
Different types of stains respond to different types of chemical
agents and
removal methods.
If the wrong chemicals and methods are used they may spread the
stain, and carry it
deeper into the stone and
permanently set it or create a whole new stain.
Some times the cause of the
stain is unknown. If this is the case than ask yourself a few
question and look around to see if the stain fits into one of the five categories, also
color
may provide a clue.
COLOR CLUES TO STAIN IDENTIFICATION |
|
STAIN COLOR |
POSSIBLE CAUSE |
Black |
Oil, grease, tar, asphalt, ink, shoe polish, mould, moss, fungus, mildew, animal feces, vegetation, dirt |
Brown Shads |
Coffee, tea, foods, chocolate, grease, oil, algae, moss, vegetation dirt, wood (tannin), tobacco, urine, animal feces, rust, copper, bronze, dyes, plant fertilizer |
Reds Shads |
Foods, fruit drinks, blood, ink, dyes, rust, plant fertilizer, dirt |
Orange |
Foods, fruit drinks, rust, dyes |
Green |
Algae, mildew, foods, ink, dyes, copper, bronze |
Yellow |
Eggs, mustard, oil, grease, urine, rust |
Amber |
Varnish, polyurethane |
Blue |
Plant fertilizer, ink, dyes |
Bluish-Greenish |
Copper, bronze |
Gray |
Aluminum, efflorescence, paper |
White |
Aluminum, efflorescence, plant fertilizer, paint |
Clear |
Eggs, shellac, lacquer, varnish, urethane, polyurethane |
Other |
Paint, ink, crayon (wax), dyes, cement coloring stains, pigmented sealers, colored past waxes, colored grouts |
STAIN REMOVAL
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In order to draw out the staining
substance that has been absorbed into the stone an
absorbent material needs to be applied to the stained area. This process is referred
to
as a poultice.
There are several premixed wet poultice
products available, as well as powder poultices
that only require the addition of water to activate them. They are more convenient and
safer to use
than formulating your own stain remover. These usually can be purchased
at a marble or tile store. I highly recommend that this type of product be part of your
stain removal kit so that when a staining situation does happen you can address it as soon
as possible. Make sure that the product you buy is
compatible with the stone you
intend to use it on. Example...Some
products will say that it is not to be used on some
types of stones, read the label thoroughly and do not just take the word of the
salesperson for granted.
Poultices are more effective when plastic is
placed over them and taped down. This
prevents the poultice from drying out to quickly, allowing the chemical to work on the
stain. The poultice should remain covered approximately 24 hours, then the plastic
removed. If the poultice is not dry at this time it should be allowed to air dry so the
staining substance can be drawn into the poulticing material. When poultice is dry
remove using a wooden or plastic spatula and rinse well.
The stone may have a dark damp spot where the
poultice was, this may take a day or so
to dry in order to determine if the poultice has worked or if another application is
needed.
Some stains require a few treatments. A good rule of thumb is...If after two applications
the stain has not changed it may be permanent or it is not responding to chemical and at
this point I would recommend that you call a stone care professional.
It has been estimated that approximately 85%
of the stains in stone and masonry materials
can be removed successfully and the remainder will either lighten to one degree or
another,
or they are permanent.
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Do not wipe a wet stain to pick up the
solution, this may spread the stain. Use an absorbent
cloth or paper towels to blot it up.
The following is a general
guideline for known stains. If in doubt call a
profession stone
care company.
STAIN REMOVAL GUIDE |
|
ORGANIC |
Mix hydrogen peroxide with a few drops of ammonia. Pour on the stain and leave until the fizzing stops. Use brush to work in. Rinse with water. If it lightens repeat. If this does not work apply the commercial poultice according to the instruction. More than one application may be necessary. |
OIL-BASED |
Apply poultice. Oil stains usually require a few application to to be removed. |
INK / DYE |
For light colored marble and limestone...
add about 1 inch of "DI DI Seven" with enough water to mix with poultice.
More than one application may be needed. I have had great success with this method. For dark marbles...Wipe with Acetone. |
BIOLOGICAL |
Spray with a solution of 3 parts bleach, 1 part water and a few drops of dish detergent. Scrub with a brush unit gone. Rinse thoroughly with clean water. |
METALLIC |
NOTE : DO
NOT USE BLEACH! |
In your Stain Removal Kit you will need some...
Tape (tan painters tape 2 to 3 in. wide)
A wooden or plastic spatula
Plastic (food warp, etc.)
Hydrogen peroxide 6 to 35%, the higher %
can be bought at a beauty supply store.
Ammonia, bleach
A product named "DI DI Seven" and "Iron Out",
KMart, WalMart and some hardware store sell them.
Acetone, lacquer thinner these are solvents that can
be bought at a hardware stone. They are safe to use
on all types of stone.
A nylon scrub brush and rubber gloves
Stains can be categorized as...very light, light, moderate, severe, and very severe.
Moderate to very severe oil
stains in granite and quartzite can prove to be stubborn to
remove using a commercially premixed poultice.
If you have moderate to very
severe staining of any kind or you're not quite sure what
caused the stain it is recommended that before you attempt to remove the stains that
you consult with a qualified stone care professional first.
STAIN PROTECTION ![]()
The stone should be treated with a water and or oil repellent.
These types of treatments
modify the absorption factor of the stone and minimizes staining.
There are several factors to
consider when choosing a sealer for stain protection.
The type of stone ( marble, granite,
etc.)
Its absorption %...See Stone
Types
The type of finish...Polished...Honed...Textured
The stones location and the possible
staining conditions.
The Color Clue chart above will give you an idea.
Is the product ( sealer ) formulated for
a dense stone or
for a stone with large pores? Sealers are not
alike in certain respects.
What is the service life...6
mos.,1, 2, 5,10 yrs. This is how long the
product will work before it needs to be reapplied.
Will the product darken the stone?
The products and methods used to maintain
the stone after it is treated.
Some products and methods will shorten the sealers service life.
It is important to understand what a repellent treatment will and will not do.
They will not prevent etching
from acidic foods and beverages on marble and limestone.
However, a treated surface will minimize the degree of etching by keeping the offending
substance at the surface not allowing the damaging effects to migrate deeper into the
stone to cause severe etching.
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A treated surface is not
a total guarantee against staining. Repellent treatments
are not stain-proofers. If an offending substance is
left in contact for a prolonged period
of time a stain may develop, however it will not become deep seated. Therefore, care
should
be taken to remove any spills or foods from the surface as soon as possible.
Treating the stone does
not make it maintenance free, it still needs to be
maintained
with the proper stone care products. Honed and texture surfaces in interior settings will
receive further protection from using a "stone soap". Stone soaps dress the
stone leaving a
residue behind which may act as a sealer and a soil releasing agent.
Understanding stone and the
products that are available for stone care leads to realistic
expectations and are vital elements for a successful stone maintenance program.
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