GacoFlex U-66

GacoFlex U-66 is a two component, fire-retardant polyurethane elastomeric waterproofing coating.

---

USAGE

Use on roofs, mechanical room floors, walking and traffic decks where excellent weathering, fire retardance, toughness, fast cure and good solvent resistance are needed. Suitable substrates include concrete, plywood, sprayed in place polyurethane foam and metal.

STANDARD COLOR

• U-6601 Oyster
• U-6602 Pewter
• U-6616 Shale
• U-6618 Adobe

---

APPLIED PRODUCT DATA

WEATHERABILITY

Excellent durability and chalk resistance, off-whites will show some yellowing.

CHEMICAL RESISTANCE

Good salt, acid and solvent resistance. Fair alkali resistance. Excellent hydrolytic stability to 160°F (71°C).

TENSILE

• ASTM D-412
• Strength: 2600 ± 100 psi (17.93 ± .69 MPa)
• Elongation: 300% ± 25%
• Permanent Set at Break: 25% Maximum

HARDNESS

• ASTM D-2240
• 90-95 Shore A

TEAR RESISTANCE

• ASTM D-624 Die C
• Lb./In. Min. 400 ± 25 (71.4 ± 4.5 kg(f) / cm)

WATER ABSORPTION

• ASTM D-471 Max.
• 7 days R.T. 2.0%

WATER VAPOR PERMEABILITY

• ASTM E-96 Procedure B. Max.
• 100% R.H. Difference 7 days at 23ºC.
• 0.02 Perm Inches

TOXICITY

Inhaling high vapor concentration of solvents could have adverse health effects. Part B contains isocyanate prepolymer, which is toxic if heated in a confined area and inhaled as particulate matter. Wear respiratory protection if material is heated, sprayed, or used in a confined space. Refer to MSDS for more information.

ADHESION

Adheres well to wood, sprayed-in-place polyurethane foam, neoprene, Hypalon® coatings and GacoFlex primers. See primer recommendations below (or Primer Recommendation Chart), for specific surfaces. The GacoFlex primer-sealer system is recommended to minimize blistering when coating over porous concrete. GacoFlex U-66 series coatings can be re-coated when set to touch or as much as a week between coats may be allowed, as long as the surface is clean and dry. Use neoprene primer over U-66 to assure adhesion of Hypalon topcoats, when used.

---

PACKAGED PRODUCT DATA

COVERAGE

Sq. Ft./Gal./Mil. 1195 to 1210 (29.3 to 29.7 m² / L/.02 mm)depending upon color.

SOLIDS

• Weight:
  • Method 4041
  • Fed. Std. 141
  • 83.0% to 85.0% depending upon color
• Volume: 74.5% to 75.5% depending upon color

V.O.C.

Conforms to V.O.C. regulations. V.O.C. content is 210 grams per liter.

FLASH POINT

• ASTM D-56 (Tag Closed Cup)
• Part A 22ºF (-6ºC)
• Part B 60ºF (16ºC)

STORAGE STABILITY

Part A and B, 1 year at 50 to 80ºF (10 to 27ºC).

THINNER

T-5116 for brush, roller or spray. T-5118 for troweling.

---

APPLICATION

PRIMER

• Polyurethane Foam: No primer necessary
• Wood: No primer necessary
• Concrete: Standard GacoFlex sealer system U-5677/E-5320 or E-5481.
• Metals: GacoFlex E-5320 and/or E-5388, GacoFlex U-5677

MIXING INSTRUCTION

Examine both components for liquidity. Stir Part A to suspend any settled pigment. Combine equal volumes of Part A and Part B. Mix thoroughly (power mixing is mandatory for quantities over two gallons).

POT LIFE

Pot life varies with the temperature of the material; including the temperature at which the material is stored. As a general guide, pot life can be expected when material temperatures are as follows:

• 60ºF (16ºC) - Approximately 2 Hours
• 78ºF (26ºC) - Approximately 1 Hour
• 96ºF (36ºC) - Approximately 1/2 Hour

Brush, roll or notch trowel as mixed. Do not thin more than 5%, so as not to exceed 250 grams/liter VOC.

For spray application, thin if necessary with GacoFlex T-5116. Apply with conventional spray gun or with airless spray equipment. When thinning for trowel application at temperatures above 80°F (27°C), use GacoFlex T-5118 trowel thinner to prevent rapid skin formation on the surface. Thoroughly clean spray equipment with GacoFlex T-5130 thinner. Circulate through lines and gun until residual U-66 is removed. Flush with clean thinner. Consult Gaco Western's Spray Guide SG-Urethane for more information.

See General Instructions GW-3-1 for safety and storage notes, and GW-3-3 for complete application details.

Note: Surface and ambient temperature should be a minimum of 40°F (4°C) to allow coating to cure properly.

CURE

Applied coating will set in eight hours at 70°F (21°C) and can be used for light foot traffic after 24 hours cure. For vehicle traffic, an additional 24 hours is necessary.

A special accelerator, U-5651, is available to increase the rate of cure. Up to ¼ ounce per gallon (7 ml per 3.78 L) in Part A may be used to double cure rate; pot life will be reduced accordingly.