Surface Preparation Methods
Shotblasting
This method is a one-step process which strips, cleans and etches simultaneously. All dust and
contaminants are collected by a vacuum system which permits the immediate application of
the coating system. All deposits of oilor grease must be removed before shotblasting.
Mechanical Scarification
This method uses a machine which grinds, cuts, sands, or breaks away the top layer of the
surface to expose a clean, fresh exterior. All deposits of oil or grease must be removed
before scarifying.
Sandblasting
Either wet or dry blasting can be used. Blasting of concrete requires removal of loose and
powdery concrete along with laitance. Vacuuming or air blasting is required to remove all
sand and dust. All deposits of oil or grease must be removed before blasting.
Types of Surfaces
Concrete
The concrete must be thoroughly cleaned with a strong detergent to remove grease and oils.
The floor should be thoroughly wetted before application of detergent and thoroughly rinsed
after cleaning. Any loose concrete should be removed. Holes and cracks should be filled before
application of a coating. Coating older but uncoated concretefloors is done in much the same
manner as new concrete.
Steel
Minimum surface prep required is sandblast to ensure removal of rust, mill scale, oxidation or
old coatings. If this is not possible, an acceptable alternative is mechanical preparation, if
carefully done. A degreasing solvent wipe is recommended prior to blasting or sanding.
Blasted surfaces must be coated within 8 hours to prevent rust bloom.
Wood
A clean, sound wood surface is required. Remove any oils and dirt from surface by suitable
means, using degreasing solvent or strong detergents. Sanding or mechanical cleaning is
then required to remove loose or deteriorated surface wood to obtain the proper surface
profile.
Plastic
Sandblast or power sand lightly to remove surface contaminants, old coatings, etc. New
plastic surfaces require light sanding or brush blast to remove mold release and other
adhesion inhibitors. A solvent wipe is recommended before blasting or sanding.
Painted Surfaces
If the paint is peeling or degrading in any way, it should be completely removed by sanding,
blasting or stripping. If previous coating is completely intact, the surface may be cleaned with
a strong detergent or solvent and scuff-sanded to remove the gloss. If there is any indication
that lead paint is present, EPA procedures must be followed.