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Acid Etching
Concrete Floors
Summary
Concrete floors require preparation before applying
a paint, high-performance coating system, stain
or a concrete sealer. The preparation usually
involves cleaning the surface to remove oil and
other unwanted contaminants then "profiling"
the concrete by etching with acid or by mechanical
abrasion.
If the concrete does not have
heavy oil contamination, Great Lakes Laboratories
Clean 'n Etch will provide both the cleaning and
the profiling in one operation.
For concrete with heavy concentrations
of oil or other contaminants, clean the surface
first with Great Lakes Laboratories All Purpose
Prepaint Degreaser and then apply the Clean 'n
Etch for final cleaning and profiling of the surface.
New concrete may have been treated
with a "cure & seal" to slow water
loss during curing. Clean 'n Etch will remove
many of these compounds. Test by applying a drop
of Clean 'n Etch to the surface. If small bubbles
appear, the Clean 'n Etch is reacting with the
cure & seal and will remove it. If no bubbles
appear, Clean 'n Etch will not remove it.
If the concrete has been steel-trowelled,
the surface will be very smooth. This finishing
technique works fine cement particles to the surface
creating a very hard, dense finish. Steel-trowelled
floors require a 1:1 mixture of Clean 'n Etch
with water and may require multiple applications
to achieve the desired profile.
Equipment
- Plastic sprinkling can or
3 gal. plastic garden sprayer
- Push broom with natural or
synthetic bristles
- Water for rinsing
Usage tips
- Work in 10'x10' sections.
Working in larger sections may prevent rinsing
before the solution begins to dry resulting
in white, powdery residue.
- If available, use a squeegee
or wet-dry vac to remove the etching solution
before rinsing.
- Do not apply the solution
with a mop. Mopping smears the solution over
the surface and does not supply enough solution
uniformly for effective etching.
Optional Equipment Usage
tips - Continued
- We do not recommend using
a scrubbing machine as the brush or pad may
be contaminated and may not provide sufficient
agitation of the surface.
- Long-handled squeegee
- Wet-dry vacuum
Method
- Dampen a 10'x10' section
of the floor. A little water on the surface
helps activate the etching solution.
- Apply the Clean 'n Etch solution
so that a uniform film covers the section to
be treated.
- Allow 5 minutes contact time.
- Using the pushbroom scrub
the solution into the floor working in one direction
and then scrub across the surface at 90° to
the first direction.
- Allow the solution to remain
on the surface for an additional 2 - 5 minutes.
- If available, use a squeegee
to remove the etching solution before rinsing.
Otherwise, rinse using plenty of water. Scrub
the surface while rinsing to insure complete
removal of the etching solution.
- Move to an adjacent area
and repeat the process.
Troubleshooting
- A white haze, white streaks
or white, powdery dust on the surface after
drying is caused by waiting too long before
rinsing or by inadequate rinsing. The white
powder is a combination of cement particles
released from the surface and a precipitate
byproduct of the etching reaction, insoluble
calcium phosphate.
Remove as much as possible by sweeping, scraping
or vacuuming. A light dusting typically will
not show through a clear coating and will not
affect adhesion.
- Look for areas on the treated
surface that are darker or glossier than the
rest of the treated surface. Water beading or
breaking on these areas signals that the surface
is not ready for coating application and should
be treated again.
- If water soaks into the
treated surface without beading or breaking
and the surface has the degree of profile specified
by the coating manufacturer, the surface is
ready for coating application.
- Neutralizing the surface
after etching is not required because Clean
'n Etch is self-neutralizing. Once the bubbling
stops, the remaining mildly acidic solution
is easily removed by thorough rinsing.
For Technical Assistance
Call:
1-800-888-1105
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