DeFelsko PosiTest AT v.4.0 - Manual (Page 3)

Step 1: Dolly & Coating Preparation Step 1: Dolly & Coating Preparation
Dolly Preparation
1. To remove oxidation and contaminants, place the included abrasive pad on a
flat surface and rub the base of the dolly across the pad 4-5 times.
2. As required, remove residue left from the abrading process using a dry cloth
or paper towel.
Coating Preparation
1.
Lightly roughen the coating using the included abrasive pad.
As coating abrasion may introduce flaws, it should only be used when
necessary to remove surface contaminants, or when the bond strength between
the adhesive and the coating is insufficient for pull testing.
2. To promote the bond between the dolly and the coating, degrease the area of
the coating to be tested using alcohol or acetone to remove any oil, moisture
or dust.
Ensure that any alternative abrasion techniques, degreasers or adhe-
sives do not alter the properties of the coating. Test by applying a small amount
of degreaser or adhesive to a sample area and observing effects.
Step 2: Adhesive & Dolly Application Step 2: Adhesive & Dolly Application
Adhesive Selection
The adhesive included in the PosiTest Adhesion Tester kit has been selected due
to its versatility. This adhesive has minimal impact on a variety of coatings and
has a tensile strength exceeding the maximum performance capabilities of the
pressure system under ideal conditions. Other adhesives may be preferred based
on requirements such as cure time, coating type, working temperature and pull-
off strength. Quick curing one-part cyanoacrylates (super glues) may be sufficient
for painted surfaces, but two-part epoxies are preferred for porous or rough coat-
ings
Dolly Application
1.
Mix the adhesive per manufacturer’s instructions and apply a uniform film of
adhesive on the base of the dolly (approximately 2-4 mils or 50-100 microns
for best results)
2. Attach the dolly to the prepared coating test area.
If the coated surface to be tested is overhead or vertical, a means to
hold the dolly in place during the cure time may be required, i.e. removable tape.
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NOTE:
NOTE:
NOTE: