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CONCRETE FLOOR COATINGS:
Frequently Asked Questions & Answers
Q: Why doesn't epoxy peel under hot car tires?
A: Epoxies exhibit much greater adhesive strength than other types of
coatings. Traditional store bought floor paints are mostly oil base type
(alkyds) or latex/acrylic. Automobile tires generate a fair amount of
heat when spinning on pavement. When the tires roll onto a painted
surface, the heat softens these general purpose paints. The combination
of the heat and pressure caused by the weight of a vehicle causes the
paint to stick to the rubber and lift from the substrate. The chemically
cured film of a 2 component epoxy is not subject to this softening
caused by heat and therefore will not lift or peel like a conventional
paint.
Q: How long will epoxy last on my floors?
A: If floors are properly prepared, epoxies like MAGNATILE™ will offer
many years of service. Naturally, the severity of the operating
environment will be the major factor. Regular maintenance will also
extend the life of an epoxy installation.
Q: My floors were just painted last year with
epoxy and they're peeling already — Why?
A: Most epoxy coating failures are a result of improper or incomplete
surface preparation. Acid etching is mandatory on bare concrete surfaces
but acid will not remove grease or oil deposits. The degreasing process
must be performed first and followed through completely by thoroughly
removing all emulsified materials from the surface. In addition, acid
wash materials must not be allowed to dry on the surface. Failing to
thoroughly remove the etch salts produced will interfere with the bond
of the coating. Attempting to acid etch floors that have been sealed or
contain surface treatments such as curing compounds and hardeners is a
mistake and will not provide a profile for coatings to adhere correctly.
These materials cannot be removed by acid etching and shot blasting or
scarifying is the only solution.
Q: Can I apply MAGNATILE™ over pre-existing
paints or other coatings?
A: MAGNATILE™ should be applied over existing coatings ONLY if the old
coating is firmly adhered to the concrete. Perform the adhesion test as
described in this document. Floors that have existing coatings that are
questionable should be chemically stripped and acid etched or
mechanically stripped by shot blasting to remove as much of the coating
as possible. In cases where the coating cannot be removed, a coarse
sanding of the floor can provide a "profile" for MAGNATILE™ to adhere
to. Test spots are always recommended.
Q: Will automotive fluids or gasoline affect
MAGNATILE™?
A: MAGNATILE™ is resistant to all automotive fluids including brake
fluid, gasoline, diesel fuel, transmission fluid, battery acid, etc. It
is also resistant to solvents like xylene and lacquer thinner. The most
important thing to remember is that resistance means that spills will
not damage the surface if cleaned up in a timely manner. Leaving a spill
on a surface for an extended period of time could cause softening of the
coating not to mention that it is also dangerous and of poor
housekeeping procedures.
Q: How much chemical resistance does MAGNATILE™
have without a clear top coat?
A: Please refer to the solvent/chemical resistance chart included in
this document.
Q: My floors are very grimy and greasy — What
do I need to do before I can coat them?
A: Depending on the depth that the contaminants have penetrated the
slab, thorough degreasing followed by etching could be sufficient
preparation for good adhesion. If the contaminants are widespread and
deep, mechanical abrasion like shot blasting may be the only method that
will work correctly. Prior to being abrasive blasted, the concrete must
be free of oil and grease or other penetrating materials. Oil and grease
deposits cannot be removed from concrete by blasting. The contaminants
will merely be driven deeper into the concrete. Because solvents may
carry the oil deeper into the concrete, detergents or emulsifying agents
are recommended for chemical cleaning prior to abrasive blasting. As in
the blasting of steel, the air source should be checked periodically for
the presence of oil.
Q: Does MAGNATILE™ require any sealer?
A: Sealers are often used on raw, porous substrates to prevent
outgassing and excessive penetration of the top coat. I have seen a few
older residential garage floors that had never been painted before,
which “drank up” close to twice the amount of 100% solids material they
normally would have required. There was so much air in the slab that
large bubbles rose to the surface leaving craters as they broke which
did not flow back together. The use if a sealer would have eliminated
this problem.
You can determine if this situation exists with a careful inspection of
the surface. After acid etching, allow the surface to dry thoroughly for
48 hours. On the bone dry surface, gently sprinkle some clean water on
the etched surface. Watch the water carefully. If the floor sucks up the
water quickly, it would be a wise choice to use a sealer prior to
coating with MAGNATILE™. A sealer will penetrate the surface and
displace the air that would normally cause problems with 100% solids
material. Sealing is always worth the extra step as it provides better
uniformity to the bare concrete, reduces topcoat consumption and gives
an overall better looking finish. MAGNATILE™ Moisture Tolerant 2
Component Water Base Epoxy Sealer is now available for these situations.
Q: Is acid etching really enough preparation?
A: The coating bond achieved on a shot blasted concrete floor may be
greater than the bond to an acid etched floor. However, if acid etching
is performed properly, the coating bond is more than sufficient to
withstand the conditions found in most garages, shops, warehouses and
factories. Etching is designed to remove a very thin layer of concrete
and provide a “profile” for good adhesion. Keep in mind that any grease,
oils or contaminants on the surface will interfere with the etching
process and must be addressed before acids are used. After etching, a
“water drop” test should be used to determine if the surface is clean.
Water will bead up on surfaces contaminated with oils and grease and on
floors treated with curing compounds or in the presence of a sealer.
Q: What does 100% Solids mean — Is it a water
base?
A: 100% Solids coatings contain no solvents or water. They are
essentially solvent base coatings formulated without the need for
solvents because their viscosities are low enough for application as
supplied. When 100% solids coatings are applied at a given thickness,
the cured film is of equal thickness because there are no volatiles
(water or solvent) to evaporate. For example: One coat of a 60% solids
epoxy applied at 10 mils thickness on a floor will cure at 6 mils thick.
A 100% solids epoxy applied at the same 10 mils thick, cures 10 mils
thick.
Q: Will MAGNATILE™ chip or get scratched?
A: All coatings will experience damage. Dropping a heavy steel object
can pop a chip out of an epoxy coating and dragging a heavy, sharp
object could cause scratches. As long as the coating exhibits good
adhesion, a damaged area will not spread and repairs can be made.
Q: How do I repair damages or chips in
MAGNATILE™?
A: Repairs can be made by mixing a small amount of the MAGNATILE™
components and flowing into the damaged area. If decorative chips were
used they should be sprinkled over the patch and the repair will cure
virtually invisible.
Q: We do a lot of welding — Will the coating
get burned or scorched?
A: Direct flame or a shard of hot steel can burn or scorch the surface.
This type of damage is repairable by sanding out the scorched area. In
the case where decorative chips were used, some fresh coating can then
be applied to the surface and new chips broadcast over the wet epoxy.
Flying sparks from grinding or welding will not generally burn the
surface.
Q: Does epoxy get slippery?
A: Epoxy coated floors will get slippery when wet. Spilled water and
vehicular fluids will cause a hazardous situation if not cleaned up
promptly.
Q: Do I have to use non-skid aggregate?
A: Non-skid aggregate is not mandatory but it is highly recommended if
your operating environment is one that frequently gets wet like a
commercial kitchen or processing area getting frequent wash downs. Many
shop owners don’t like the idea of aggregate because it makes their
floors more laborious to mop and clean. If the choice is made to forgo
the use of non-skid materials, a regular maintenance routine should be
established and documented so as not to create a hazardous situation and
liability for employees and possibly customers.
Q: Moisture testing on our floor revealed
dampness under the plastic — What can we do now to coat it?
A: An American Concrete Institute publication suggests that the moisture
content of concrete is excessive for paint application if moisture
collects at the bond line between the concrete and the paint before the
paint has cured. If the moisture test has failed the first time it needs
to be re-run. This time, you must determine the actual time required for
moisture to collect on the underside of the sheet. During the test, the
ambient conditions (sunlight, temperature, and relative humidity) should
simulate, as much as practical, the conditions that will exist during
paint application and curing. Compare the time for the moisture to
collect with the paint curing time--a value that should be supplied by
the paint manufacturer. The concrete is adequately dry if the paint will
cure in a time shorter than that required for moisture to collect under
the plastic sheet.
In this situation, the surface should be degreased if necessary and then
acid etched, flushed thoroughly and allowed to dry. The use of a clear
water base epoxy sealer can solve this problem because the material is
designed to be applied to damp surfaces. MAGNATILE™ 100% Solids Epoxy
can be applied 2 to 4 hours after the sealer is applied.
Q: We've just poured a new concrete slab — Can
I coat it with MAGNATILE™?
A: In common practice, a minimum of 28 days is necessary before any
freshly poured concrete can be coated. This is usually sufficient to
allow excess moisture to leave the slab and prevent any moisture related
disbondment. Additionally, as concrete sets and cures, a thin layer
forms on its surface called laitance. This weak layer is a result of
cement paste and fine aggregate floating to the surface as the concrete
cures. If the laitance is not removed before coating application, the
coating will most likely disbond. Acid etching or mechanical abrading is
required to remove this layer.
Besides residual moisture content and laitance, a few important
questions need to be answered regarding treatments that may or may not
have been used that could cause problems. You need to know whether any
sealers, curing agents or surface hardeners were used in finishing of
the slab. If you don't know these answers offhand, the contractor who
poured the job should be able to answer them. The “water spot” test
discussed in this document will quickly determine if the slab was
treated with materials that could cause adhesion problems.
Concrete hardeners are usually sodium silicate solutions or metallic
fluorosilicates. Where hardeners have been used, the concrete will
usually appear glossy and may be a grayish brown color. The surface
generally cannot be scratched with a coin. Hardened concrete cannot be
successfully coated unless special methods are used to prepare the
surface.
When a surface hardener or curing agent has been used, acid etching is
not always effective in creating a "profile" to which a coating will
adhere properly. The surface should be about as rough as a piece of #80
or #100 grit sandpaper to be ready for coating. Some surface finishing
methods can give this sort of profile and acid etching will always do
the job as long as the slab has no treatments as mentioned above.
Sealers will most always prevent acid from doing its job and it's not
advisable to coat over most sealers unless specific types were used in
anticipation of top coating. In this case, only chemical striping or
shot blasting will be the choice method of preparation.
Of the 2 methods of surface prep normally used, acid etching is the
common method for any surface that will not be subject to extremely hard
industrial use. Shot blasting is the preferred method when concrete is
in poor condition or will be receiving a troweled topping or is a new
slab and has a surface that cannot be prepped with acid.
Q: I've heard that polyurethane is better on
floors than epoxy — Can you explain the differences?
A: Epoxies demonstrate much greater adhesion to concrete than
polyurethanes (aka - urethane). Urethanes offer better abrasion
resistance and have greater flexibility but are worse for adhesion to
almost all surfaces. Typical high performance concrete floor coating
systems are usually a 2 or 3 step coating processes after the initial
floor preparation.
Concrete is usually coated with epoxy as the first and second coats if
necessary to gain best adhesion to the slab. In situations where extra
abrasion and/or chemical resistance properties are required, a top coat
of a two component urethane either clear or pigmented is applied as the
final coat only. Abrasive grit is sometimes mixed with base coat or
broadcast into the midcoat or top coat to provide slip resistance. These
urethane top coats are occasionally single component moisture cure
urethanes but most often a highly chemical resistant two component
system used in strong chemical environments or in airplane hangers to
provide skydrol (hydraulic fluid) resistance.
While urethanes are better for their chemical and abrasion resistance
properties, they should never be applied directly to concrete. When
making a choice regarding a coating system, always focus on surface
preparation as the most important aspect, and then consider the coating
based on the operating environment of the floor. Epoxies are the
workhorses of the industry. Polyurethanes are chosen as auxiliary top
coats based upon the usage requirements of the floor.
Q: Are there any isocyanates in epoxy?
A: No. Only polyurethanes contain isocyanates.
Q: Can I rent a shot blaster and do my own
floors?
A: Shot blasting equipment can be rented for personal use but may be
difficult to find. Rental costs will be moderately high and I would
recommend that you compare these costs to a contractors quote to perform
the blasting for you. There are many companies that specialize in
blasting and prep work only and you can find them in your local yellow
pages under “floors - industrial”. The machinery is not difficult to
use. You just need to be aware of the actual time it may take to do the
blasting on your own. Check the specifications of the machinery you plan
to rent that the size and rating of square feet per hour is sufficient
to complete your footage without having to keep the machine longer than
anticipated. Rental rates can quickly add up to equal the contractors
quote and more. If you decide to rent, be sure to check that you have
the power to run a machine that may require 220 volts. There are smaller
110 volt machines as well as units that run on gasoline and propane.
Consider a scarifyer also which will cost much less to rent.
Q: Can I recoat MAGNATILE™ at a later date with
a urethane clear coat?
A: If your operating environment warrants the use of a chemical
resistant top coat, I'd advise that you apply it now when MAGNATILE™ is
first installed. There are a few reasons for this I'll explain After the
epoxy has fully hardened, its surface will have to be abraded to promote
good adhesion for a top coat. If a clear is applied within 48 hours over
MAGNATILE™, no abrasion is necessary. Also, if the floors are used and
soiled, you'll need to be very certain they are clean enough to recoat.
Dirt, grease, oils or any contaminants could ruin the topcoat
application and it would be a waste of money and labor.
Q: Can I spray MAGNATILE™?
A: You can spray any type of coating including MAGNATILE™ but we don't
recommend it. Spraying would mandate the use of dual component airless
spray equipment which mixes the two components of the product at the
spray head. Attempting to spray MAGNATILE™ using conventional air or
airless spray equipment using premixed product would cause too many
problems considering the relative short pot life compared to other types
of general purpose epoxies or urethanes.
Q: Other epoxy systems I've seen have a much
longer pot life than MAGNATILE™ — Why is that?
A:MAGNATILE™ is formulated from a highly reactive cycloaliphatic amine
curing agent. As a 100% solids epoxy, MAGNATILE™ has an extremely long
pot life for a system of its type. The much longer pot life you may see
with other systems is because they are not 100% solids content but lower
solids, solvent containing systems or even water base products. The
solvent type systems will generally have a very strong odor and a flash
point under 100ºF making them flammable and much more dangerous to use.
Water base epoxies have good durability and also a long system pot life
but like the solvent base systems, they are applied in very thin films
and don't even come close to the longevity of 100% solids products.
MAGNATILE™ is so easy to apply with its low viscosity and self leveling
properties that the 60 minute pot life is really not a problem.
Q: My local store sells a single part floor
paint called a modified epoxy — Will this work on my floors?
A: Single component paints labeled as an epoxy or a modified epoxy are
nothing more than an oil or alkyd type coating that may contain a binder
referred to as an “epoxy ester”. These coatings do not exhibit the type
of adhesive strength, chemical or abrasion resistance found in
chemically cured 2 component epoxies. We don't recommend any single
component paints for coating concrete floors unless the areas are
subject to foot traffic only.
Q: Can I become a MAGNATILE™ distributor and do
installations for other people?
A: Absolutely! We welcome all dealer inquiries. If you're involved in
the automotive, industrial, institutional or agricultural trades and you
have the market to sell or install floor coatings, please contact
customer service at 1-800-922-9981. |
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