Important Note: Ultra Block® backing
material must be compressed to a
minimum of 25% when inserted into the
joint for the UL rating.
Limitations: Not recommended for use:
• In potable water tanks.
• In areas contaminated with oil, grease,
wax, bitumens, curing compounds,
concrete sealers or mold-release agents.
• Under water in sewage disposal or
waste water treatment plants or other
facilities subject to harsh chemicals such
as acids, strong alkalis, ketones, etc.
Pecora GC2+ Synthacalk two-part
polysulfide sealant should be used for
• As a structural component or in
longitudinal expansion joints that are
intended to be used as a constant
• Submerged in intensive chlorinated
water applications consistently exceeding
5 ppm – chlorine concentrations.
4. TECHNICAL DATA
Applicable Standards: Meets Federal
Specification TT-S-00227E, Type II, Class A;
ASTM C-920-98, Type M, Class 25, Grade
NS, Use T, M, A and O. Dynatred® also
exceeds the test requirements of
ASTM C-1247 for Sealants Exposed to
Continuous Immersion in Liquids.
Surface Preparation: Surfaces must be
clean and dry. The presence of moisture
may cause gassing before the sealant
achieves ultimate cure. Oil, grease, wax,
form-release agents, curing compounds,
bitumens, laitance and old caulking
materials must be removed by sandblasting
or sawing to sound, virgin substrates for
optimum sealant performance.
Priming: All joints must be primed before
applying Dynatred®. Pecora P-75 or P-150
primer is recommended on masonry and
P-120 on aluminum, steel and galvanized
metal. Primer must be dry before the
application of Dynatred®. Primers should
not be allowed to dry over eight (8) hours
165 Wambold Road
Harleysville, PA 19438
3. PRODUCT DESCRIPTION
Dynatred® is a two-part, chemically-curing,
cold-applied elastomeric sealant with the
effectiveness of self leveling, traffic-grade