Flex HE903 - Manual (Page 2)

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Flex Membrane International Corp. 2670 Leiscz’s Bridge Road, Suite 400, Leesport, PA 19533
Tel: (610) 916-9500 Fax: (610) 916-9501 www.FlexRoofingSystems.com
Page 2
USES
Flex HE903 Modified Bitumen Adhesive is especially formulated for horizontal applications of roofing plies
and Flex SBS Modified Bitumen Membranes. It has many advantages over the use of hot asphalt in applying
SBS based Modified Bitumen cap sheets such as its compatibility with SBS and BUR roofing memebranes.
Flex HE903 Modified Bitumen Adhesive is ready for use as shipped.
SURFACE PREPARATION
All surfaces to be coated must be dry, clean and free from oil, grease, rust, scale, loose paint and dirt. For
best adhesion over worn or previously coated surfaces, an application of Asphalt Primer is recommended.
APPLICATION
Stir in container and apply by notched squeegee or commercial grade spray equiment. A notched squeegee
with notches 1/4" long, 1/8” deep, spaced on 1” centers, is preferred for smooth surfaces. For irregular
surfaces, the notch should be 1/4" deep. Average application rate over smooth surface is 1.5 gal/100 sq. ft.
Over porous substrates, the coverage rate will increase to approx. 2 gal/100 sq. ft. DO NOT OVER
APPLY. Sufficient adhesive should be applied at laps to result in a visible bead of adhesive at completed lap
edge. Flex SBS modified bitumen should be cut in maximum 18 foot lenghs and membrane allowed to relax
on job site. For best results, it is recommended that the end and side laps be rolled with a weighted roller
immediately after installation. For cold process assemblies, apply uniformly between layers of roofing plies at
the rate of 1.5 to 2 gallons per 100 sq. ft. DO NOT OVER APPLY. For spot application of the first layer
to smooth, non-nailable surfaces, adhere with 9 inch diameter spot application 18 inches o.c. staggered in two
rows.
Flex HE903 Modified Bitumen Adhesive is suitable for spay application using a Garlock Commander with
Hot Max spray rig or a Graco 733 spray rig, or similar. The pump must be able to deliver at least 2000 to
3000 psi. The spray tip must be 0.080” or larger, without a breaker bar. O rings should be made from Viton.
The hose diameter must be at least 3/4” I.D; the last 50 feet can be 1/2" I.D. For hose lengths longer than 200
feet, 1” I.D. is recommended. The product must be at least 70ºF at the tip for spray applications.
IMPORTANT
Flex Modified Bitumen Adhesive does not freeze. Cold weather will cause it to stiffen. Store unopened
container in a warm area at least 24 hours before using. Do not thin. Do not use with Modified Bitumen
Membranes with polyethylene backing. For use with modified bitumen membranes that are sand backed or do
not contain polyethylene or film surfacing.
CLEAN-UP
All equipment can be cleaned with kerosene or mineral spirits. Use care when handling solvents. Clean hands
with a waterless hand cleaner.
CAUTION
Keep out of reach of children. For external use only. Combustible. Contains pertroleum distillate. Keep
away from heat and open flame. Do not heat container or store at temperatures greater than 110ºF. CLOSE
AIR INTAKES on roof until solvents dissipate. Contains volatile solvents that might contaminate potable
water. Close container after use. Dispose of container and unused contents in accordance with Local, State
and Federal regulations.
Flex Membrane International Corp. maintains Material Safety Data Sheets on all of its products. Material
Safety Data Sheets should be read and understood by all supervisory personnel and employees before using
Flex products in your facilities.