critical aspects in the use of epoxy systems are proper surface preparation and
mixing in ratios specified by manufacturer's instructions.
directions for surface preparation always require that surfaces be clean, dry,
and free of oil, dust, efflorescence, rust and loose or flaking paint. Problems
arise when surfaces appear to be clean, but are actually unsatisfactory for
New concrete surfaces may require only a washing
with a 10% muriatic acid solution and then a thorough rinsing. Old surfaces are
the the troublemakers. Whether any curing compounds or sealers have been used,
what types of chemicals it has subjected to and how sound the surface is, must
be determined. When concrete has been subjected to certain chemicals or sugars,
it may appear to be sound when it is actually quite soft.
coatings are present on the concrete, but are in good condition, they must be
identified. For example, if a solvent based coating is put over an old alkyd or
rubber-based coating, there is a good chance of a failure because of solvent
attack. Even 100 percent solids epoxy systems can lift old coatings from the
surface. Epoxies have excellent adhesion to these coatings, but the tension
produced in curing and in use lifts them. Normally the best way to prepare
these surfaces is to scarify or sandblast.
Oil and chemical soaked
surfaces, are difficult to clean with conventional methods. Cleaning with
solvents, or mechanical abrading (scarifying) the surface is the best method.
When a concrete surface has been saturated with chemicals, specific
recommendations for preparation should come the manufacturer.
surfaces must be cleaning of all oil, rust, mill scale and old coatings. This
cleaning is best achieved by sandblasting or mechanically abrading the surface.
If there is any doubt about conditions on any surface, a sample placement
should be applied.
When selecting an
epoxy system, it is important to relate the type of surface it will be applied
to, the traffic it will be subjected to, and the types of chemicals and
temperatures it will be exposed to both during application and final use.
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268 Route 112, Patchogue, NY 11772
(800) 332 · 3883 · fax (631) 654 · 0217