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Johns Manville
Commerical Industrial Roofing Systems\SBS Modified Bitumen
SBS Modified Bitumen - Page 6
Commerical Industrial Roofing Systems\SBS Modified Bitumen
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SBS Modified Bitumen Specifications |
7A.17 Precautions For Two-Part Cold Adhesives
7A.17.1 There are some application precautions that must be taken when using these materials.
A. |
JM MBR cement products are significantly different from the adhesive materials used for built-up roofing. The mechanic must use a great deal more care since these adhesives are prepared on the job site. Roofing contractors must advise their crews to precisely follow all storage, handling, preparation, application, and health/safety instructions. JM will not accept responsibility for any use of these products that does not comply with the instructions printed on the cement base container. |
B. |
MBR Cement Activator must be stored indoors in an area maintained above 60°F (16°C) or crystallization will occur. If crystallization does occur, it can be reversed by carefully warming the container. Refer to the package label for the precise procedures. |
7A.18 Two-Part Cold Adhesive Equipment
7A.18.1 The following equipment is necessary for the safe and efficient preparation and application of JM MBR Bonding Cement.
7A.18.2 Safety and Personal Protective Equipment: The following items shall be available for, and used by, every worker:
A. |
Impervious gloves, 1 pair for each worker. |
B. |
Rubber or plastic apron, 1 for every person mixing. |
C. |
Organic cartridge respirator mask. Note: air-supplied respirators may be required for some applications. |
D. |
Chemical safety goggles, 1 for each person mixing or spraying. |
E. |
Soap and water. |
F. |
Hand cleaner. |
G. |
Supply of clean rags. |
H. |
Solvent: paint thinner, or mineral spirits. |
I. |
Portable fire extinguisher. |
J. |
Squeeze bottle filled with clean water for use as an eye wash. |
7A.18.3 The following items may be required at the job site to protect the installation and surrounding areas during application:
A. |
Heavy wrapping paper or suitable protective sheeting. |
B. |
2" (51 mm) wide masking tape. |
7A.18.4 Mixing Equipment:
A. |
Jiffy Mixer Model PS, or equivalent. |
B. |
1/2" (13 mm) electric drill motor and power source. |
C. |
Plastic graduated container for measuring activator and base material. |
7A.18.5 Application Equipment:
(Some of the items listed below are optional, depending on whether squeegee or spray application is used.)
A. |
3/16" (5 mm) saw tooth squeegee. |
B. |
Binks "Hawk 4L" Spray Unit (or equivalent) to fit a 5 gallon (18.9 liter) pail, and Type 7E2 spray gun (or equivalent) with 47 x 1/4" (6 mm) nozzle with 25 feet (7.6 m) of 3/4 " (19 mm) fluid hose and 25 feet (7.6 m) of 3/8" (10 mm) air hose. |
C. |
125 cfm (3.54 cmm), 100 psi (690 kPa) air compressor and hose. |
D. |
Clean 5 gallon (18.9 liter) metal pails. |
E. |
Solvent: paint thinner or mineral spirits. |
F. |
All tools normally used in the application of built-up roofing materials. |
7A.19 Two-Part Adhesive Preparation
7A.19.1 MBR Bonding Cement is prepared on site by adding specific amounts of MBR Cement Activator to MBR Bonding Cement Base and mixing thoroughly. The adhesive is prepared in the MBR Bonding Cement Base shipping container, a 5 1/2 gallon (20.8 liter) pail, with the use of a Jiffy Mixer mounted on a 1/2" (13mm) electric drill motor. The container of MBR Cement Activator is packaged to provide exactly the correct amount of material necessary to react with the contents of the MBR Bonding Cement Base pail (4 1/2 gallons [17.0 liters]). The Activator is heavier and has a lower viscosity than the base material. To produce a complete mix, the Activator must be poured slowly into the vortex caused by the rotating mixer. IT MUST NOT BE DUMPED INTO THE PAIL IN ONE MOTION. The mixer should be moved about the pail in an up-and-down and side-to-side motion. The mixing is complete in about three (3) minutes. Do not overmix!
7A.19.2 The mixed adhesive has a pot life that is dependent on its temperature. The mechanic will have to use the mixed material in approximately: 40 minutes at 50°F (10°C) 35 minutes at 60°F (16°C) 35 minutes at 70°F (21°C) 30 minutes at 80°F (27°C) 25 minutes at 90°F (32°C) 20 minutes at 100°F (38°C)
7A.19.3 The mixing of individual pails of adhesive should be timed so that one can of freshly mixed material is ready for the application crew. Mixed adhesive must not be stockpiled, since the material may cure to an unworkable viscosity before the application crew can use it. In cold weather, the material must be stored and mixed at room temperature.
7A.19.4 Although not recommended, mixing of quantities smaller than a full pail may be required. Using a clean container, mix the MBR Bonding Cement Base and MBR Cement Activator using the following ratios:
By Volume |
By Weight |
|
MBR Bonding Cement Base |
1.0 gal. (3.8 liters) |
1.0 lb. (0.45 kg) |
with |
with |
|
MBR Cement Activator |
0.08 gals. (9.8 fl. oz.) (303 ml) |
0.1 lb. (1.6 oz.) (45.4 g) |