Superior Epoxies systems are formulated for application over a
variety of substrates provided that proper procedures are
followed in preparation. If a particular application cannot be
found in this guide, or if your are not sure how to accomplish a
specific task as described, please call your Superior epoxies &
Coatings representative NOTE: A sample placement is always a
good idea when evaluating field conditions.
Moisture Testing
Moisture in concrete and vapor emission is an important factor
when determining the suitability of a slab for resinous toppings
or coatings. These conditions may adversely affect the bond or
final performance of epoxy systems.
Moisture traveling through concrete in the form of water or
vapor carriers salt particles which will rise to the surface of
concrete slabs. These salts are visible as dusting concrete or
laitance. When epoxy systems are placed on surfaces in this
condition, there is no way for these transitory salts to escape.
Eventually, they build up at the interface between the concrete
and the resinous material and will eventually blister the epoxy.
If this blister is broken, a white powder and/or water will be
present beneath it. As a result the bond between the concrete
and epoxy will be lost.
To test concrete for moisture prior to applying Superior Epoxies
Epoxy Coating.
Tape a 2’ x 2’ piece of non-breathing rubber or plastic sheet to
substrate.
Apply heat to draw moisture. If outside, sunlight is sufficient.
If inside or overcast, a heat lamp is required.
Leave in place for four hours.
Remove mat. A slight darkening and/or beads of moisture on the
concrete and mat respectively, indicates too much moisture.
New concrete floors should be acid etched in several small test
areas using a 10% muriatic acid solution. The areas should be
flushed with clean water to remove any traces of the muriatic
acid and laitance. The floor should then be allowed to dry
completely. A polyethylene sheet or rubber mat is then taped to
the floor and allowed to remain in place for 48 hours. If
moisture gathers under the polyethylene sheet, epoxy should
never be applied to concrete in this condition.
Existing concrete floors should be tested in the same way. Acid
etching will also determine the existence of clear sealers and
coatings on the surface. If the muriatic acid solution does not
bubble vigorously, a sealer coating is present and must be
removed. After mechanically removing the coatings, proceed with
the test for moisture as previously described. If no moisture is
detected under the mat, work may proceed with preparation of the
entire surface and application of the epoxy system.
New Concrete
New concrete slabs must be allowed to cure for at least 28 days.
(Consult your Superior Epoxies Representative for exceptions).
During this period, the concrete goes through the hydration
process and allows any excess water to leave the concrete mass.
For slabs on grades, it is imperative that the concrete
contractor makes sure that a vapor barrier is placed and is not
punctured during the pouring process. Additionally, only curing
agent compatible with the Superior Epoxies epoxy must be used
and the finish on the concrete must meet specifications. A wood
float or light steel troweled finish is the best surface profile
for application of resinous toppings or coatings. As a general
rule, curing compounds should not be used if resinous toppings
or coatings are to be applied. Curing agents may be used, but
they will have to be evaluated on a project basis to determine
if they will have to be removed or if they are compatible with
Superior Epoxies epoxies.
Once the water content/vapor emissions test is complete, Acid
etching of the entire floor area may proceed. Acid etching must
be accomplished on all new concrete surfaces. Care must be taken
when diluting the acid. Always wear protective clothing, gloves
and eye protection – or use approved respirators to ensure
proper ventilation. Always add the acid to the water.
The proper technique for acid etching should be followed. The
acid solution should be sprinkled over the entire surface using
a polyethylene sprinkling can. Do not pour the solution over the
surface and spread it around. Once the solution is sprinkled on
the floor, it should be scrubbed into the surface with a stiff
bristle broom to remove any loose concrete, cement paste or
laitance. The etching process should be observed closely to
determine areas where vigorous bubbling does not occur. These
areas will have to be mechanically scarified and etched again.
The solution should then be rinsed with generous quantities of
water. DO NOT ALLOW THE ACID SOLUTION TO DRY ON THE SURFACE.
Salts are formed by the acid reacting with the concrete and are
very hard to remove once they are dried. These salts can
adversely affect the bind of epoxy to concrete.
Once the rinsing has been completed, the floor should be mopped
dry and allowed to stand for 24 hours before proceeding further.
Remember, the temperature has an effect on the evaporation of
water from the surface. Adequate heat or additional time may be
required to insure that the surface is completely dry. The
moisture content test should be conducted again to insure that
the surface is dry prior to applying the epoxy coatings.
Epoxy products require sound concrete to insure long lasting
service life. The surface should be “sounded” with a hammer or
chain dragged to indicate hollow areas requiring repair.
Any irregularities in the surface, depressions, or high points,
will be transmitted to the final finish of epoxy coatings. These
irregularities must be removed. It is very important to remove
the high points since the coating will be at minimum thickness
at these points. Grinding or rubbing stones may be used. (See
Superior Safety Etch)
Old Concrete
After conducting the moisture/vapor test to determine
suitability of the surface for epoxy application, surface
preparation may proceed. Structural soundness of the concrete
should be determined by sounding concrete with a hammer or chain
dragging on the surface. Patching and repair materials should be
used where required. Once structural soundness has been
determined, preparation of the surface may proceed. Removal of
contamination, curing agents, sealers and existing coatings is
critical. Numerous methods are available to accomplish this
task. The method selected (i.e., shot blast, sand blast, water
blast scabling, etc.) must insure complete removal of existing
materials. Exposure of sound concrete and small aggregate
particles will occur but should not be polished or unnecessarily
rough.
Superior Epoxies epoxy may be installed over old, existing
coatings if they are well bonded and their chemical composition
can be identified. However, do not apply a solvent based epoxy
to an alkyd or urethane coating because poor inner-layer
adhesion will result and cause the epoxy to delaminate.
Solvent-free, 100% solids epoxy systems can even lift old
coatings from the surface because of the tension produced during
the curing of the epoxy.
Oil and chemical-soaked surfaces must be cleaned with solvents,
degreasing agents or by mechanical means. The chemicals should
be identified and Superior Epoxies contacted for specific
recommendations.
Wood Surface
Superior Epoxies epoxy products maybe used over wood surfaces.
On floors, never place epoxies over plank or stripped flooring.
Apply over exterior-grade plywood (“C” plugged) with an extended
glue line. DO NOT USE MARINE-GRADE PLYWOOD. As a general rule,
the thicker the plywood, the better the application. As a
minimum, use ½” plywood. Insure that it is adequately fastened
to the floor joists using ring shank or coated nails fastened
every six inches (6”). Joists should be staggered and covered
with 3” Fiberglass tape coated with a compatible low modulus
epoxy.
Metal Surface
Metal surfaces must be structurally sound and rigid. All oil,
grease and other contaminants must be remove and allow to dry.
Wipe surfaces treated or untreated with Methyl Ethyl Ketone (MEK)
or chlorinated solvent prior to application of epoxy system.
The sufficiency of the preparation of a metal surface can be
partially determined by the use of the “water surface tension
test”. This test checks the surface tension of the metal.
Individual droplets of distilled water are applied to the
surface with an eyedropper. If the surface is not clean, the
water will not spread; it will react more like a drop of water
repelling on wax paper and will remain in a hemispherical shape.
If the surface is clean and the surface tension is low, the
water will spread into a thin film wetting a relatively larger
area.
General Priming Guidelines
As a general rule, when applying epoxy toppings or patching
mortars, the same material that is used as a primer is used for
the binder as well – even when working with epoxy mortars in a
gel consistency.
Primers are used to insure that there is enough liquid epoxy
(which acts as the adhesive between the mortar and the concrete
at the interface to form a moisture barrier between the epoxy
mortar and substrate.
Before placing epoxy toppings or mortars, all substrates should
be primed unless a minimum amount of aggregate is used to create
a wet or soupy mixture with good wetting abilities.
MIXING CONSIDERATIONS
The mixing ratio of epoxy systems must not be altered under any
circumstances.
Temperature Effects
Epoxy components should be stored at moderate recommended
temperature (generally 60ºF-75ºF) at least overnight prior to
use. The viscosity of the epoxy is rather sensitive to
temperature. When the temperature is below the recommended use
temperature, the components will be more viscous, become
difficult to mix, present problems in application, and will take
longer to cure. Conversely, the viscosity of the epoxy
components will be reduced when the material temperature is
above the recommended use temperature. The components will be
easier to mix, but the material may become too thin or soupy for
the intended application. In addition, the reaction rate will be
increased, resulting in shortened available time for application
of the mixed material. Optimum results will be attained if the
temperature of the components is within the recommended use
temperature range at the time of mixing. Remember, the cure time
cannot be changed by adding more curing agent (hardener) to the
mix. Therefore, when cold weather (40ºF-50ºF) approaches and an
epoxy compound appears to be setting or curing too slowly, DO
NOT attempt to speed up the set time by the addition of excess
hardener. Also in the summer, when temperatures are higher
(90ºF-110ºF), DO NOT attempt to slow the setting time – which
might appear to be too rapid – by using less hardener. The only
effect that either of these action will have is to create a
compound which will not attain stated physical properties.
Heating Methods
Several methods are available for heating epoxies to a
temperature where effective mixing can take place. The simplest
method is by storing it in a heated area overnight before use.
When such storage space is not available and more rapid heating
is required, ovens, hot air and electrical heaters can be used
with caution. Another method and one which can be better
controlled, is to immerse the epoxy component containers in a
hot water bath.
Superior Epoxies materials and most epoxies used in the
construction industry should never be heated over 120ºF because
the working life would be too short and degradation of the
components may occur.
Cooling Methods
When cooling is required for proper application, viscosity and
adequate working life, the following cooling methods are
recommended, store material in shade, refrigerator, refrigerated
room, or in a cold water bath. In no case should the material be
cooled to the extent that adequate mixing cannot be achieved.
Aggregate Temperature
Aggregates are used with mixed epoxy components to produce epoxy
mortars and grouts. Aggregate loading usually makes up an equal
or grater proportion of the mix, therefore, their temperature
will greatly affect the consistency, workability and curing of
the mixture.
Example 1: If the epoxy components are heated for a cold
temperature application and then mixed with aggregates that are
cold, the ease of mixture workability will not occur.
Example 2: If the epoxy components are cooled to the recommended
temperature for a high temperature application and then mixed
with aggregates that are very hot, adequate working life and
desired consistency will not be achieved.
Substrate Temperature
The temperature of the substrate will not only affect epoxy
workability, but also the initial and final cure of epoxies. As
a rule, initial cure of epoxies is affected by temperature in
the following ways:
Initial (thin film) cure time is usually
6 times pot life at 77ºF.
Every 18ºF drop below 77ºF will cause the initial cure time to
double.
Every 18ºF rise in temperature above 77ºF will cut the initial
cure time in half.
Mixing
Part A = Epoxy Resin
Part B = Curing Agent
Mechanical Mixing of the epoxy components is the most efficient
and effective method. Thorough hand mixing is difficult and
takes longer than machine mixing. This additional time may be
critical considering the relative short pot life of most mixed
epoxy resin systems.
The most accurate method of proportioning is to use the
proportioned unit supplied by Superior Epoxies so that the
entire contents of both containers are mixed together. If
smaller quantities of mixed epoxy are needed, the specific
proportioning ratio should be accurately measured. These ratios
only expressed by volume.
Due to exothermic heat generated by epoxies in a large mass and
the accelerating affect on cure time, the components should be
mixed in a container that has a flat bottom and is big enough to
hold 1 ½ to 2 times as great as batch size. A clean and dry
plastic pail makes a suitable mixing container. A paint mixing
paddle (Jiffy Mixer) driven by a low speed electric or an air
powered drill should be used for the mixing. For mixing larger
volumes of epoxy, a mechanically driven paddle mixer (Muller
Mixer) is preferable since this type of equipment forces the
material together and scrapes the sides of the drum. Mixing
should continue until the compound is homogeneous. This usually
takes two to ten minutes, depending upon the restrictions of pot
life, viscosity, density, flow characteristics of the epoxy and
type of equipment used.
Aggregate Use and Mixing Epoxy Mortars
After the resin and hardener have been mixed, immediately mix in
the selected aggregate. The specified aggregate should be clean,
dry and properly graded silica or quartz sand. A very workable
sand has a small amount of fines passing through a No. 70 sieve
and usually has little or no material retained on the No. 12
sieve. For the best results in the production of epoxy mortars,
a blend of 20-50 mesh sand works well. This is especially true
when working with high aggregate loading factors, 3, 4, or 5
parts of aggregate to 1 part mixed epoxy.
The epoxy mortars used for overlays and patching consist of 1
part liquid binder filled with anywhere from 1 to 4 parts (by
volume) of the graded sand. The amount of sand depends upon the
viscosity of the binder, particle shape, and void
characteristics of the aggregate.
The following chart shows the desired loading of aggregate to
different epoxy viscosities.
Aggregate
Consistency Viscosity By Volume
Low Viscosity2,000 maximum3-4 parts
Med. Viscosity2-10 maximum2-3 parts
GelPaste1x1x1/2 parts
NOTE: For some epoxy mortars, the proportion of aggregate to
liquid binder may be as high as 9:1 by volume. This is done by
the use of very selected and well graded aggregates ranging from
coarse ½” stone down to very fine sands (200 mesh) whereby, most
of the voids are filled in with small size aggregate so less
epoxy is used.
Once everything is in the mortar mixer, mixing should continue
only long enough to get a completely “wet” aggregate and uniform
mix. The addition of the aggregate generally yields a longer
working life. An extended mixing time may develop heat and
shorten the time available for application.
Aggregate Broadcasting
To achieve a non-skid coating, apply the epoxy coating by brush,
short nap roller, or spray at the specified product coverage
rate. Broadcast sharp sand, emery, or carborundum on the first
coat while still wet. The size and amount of aggregate used will
dictate the type of skid proofing achieved. If desired, a second
application of the epoxy can be used to seal the surface.
To achieve a topping, apply epoxy binder by squeegee, short nap
roller or capable sprayer at the rate of 80 square feet per
gallon. Broadcast the aggregate at the rate of one pound per two
square feet using a spreading machine or by hand. After the
binder sets, sweep or vacuum excess aggregate and repeat above
process by applying binder at the rate of 100 square feet per
gallon. Continue this process until the desire thickness is
achieved and use one pound of aggregate per two square feet on
the final cost.
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