Instructions / Assembly

330 Central Ave. I Clark, NJ 07066 I 800.526.4236 I Fax [phone] | www.karnakcorp.com
Updated: 10.22.21
ROOFING
502MS Karna-Flex
*Read Safety Data Sheet before using this product.*
DESCRIPTION: 502MS Karna-Flex is an elastomeric, thermoplastic-rubber mastic. Its ease of
application, superior adhesion, elasticity and durability make Karna-Flex an ideal repair sealant.
Available in a brush mastic or caulking cartridge.
USES: 502MS Karna-Flex’s elastomeric properties make it an excellent sealant for prepared metal,
concrete, asphalt, spray polyurethane foam and plywood roof system details. Ideal for sealing and
waterproofing cracks and splits on BUR and modified bitumen asphalt roofs, metal roof seams and
splits, EPDM, TPO and PVC seams as well as gutters, fasteners, pinholes in metal, flashing and curb
details. Also use to seal around skylights, penetrations and roof top equipment. May be applied to
wet or dry surfaces. PVC and TPO roof surfaces should be at least 4 years old prior to application.
FEATURES, BENEFITS AND ADVANTAGES:
1. One component—no need to intermix with other materials.
2. Easy application by brush or caulking gun.
3. Superior film—forms a durable, weather resistant elastomeric membrane.
4. Superior adhesive and cohesive strength.
5. Low temperature flexibility
6. Adheres to wet or dry surfaces
SURFACE PREPARATIONS: All surfaces to be sealed must be clean, dry and free from oil, grease and
other foreign matter. Recommended application temperature is 40°F to 120°F. Excess water should be
removed, if possible, before application.
APPLICATION: General Repairs: Apply 502MS Karna-Flex by brush or caulking gun. For sealing
flashings and lap seams use fabric reinforcement between layers of 502MS Karna-Flex. Apply sealer
in a 1/16” to 1/8” width then immediately embed 5540 Resat-Mat fabric into the wet coating. Smooth
out fabric then apply another layer of sealer. Metal Roofing Repairs: For horizontal seams and cracks
1/16” wide or larger, apply 502MS Karna-Flex at an average thickness of 1/16” to completely cover
the crack. Immediately embed one layer of Resat-Mat and cover with another application of 502MS
Karna-Flex. Make sure to smooth the fabric out completely and cover. Product will cure within
approximately 24 hours. If continuing with 502 Elasto-Kote System is desired, allow all repairs to cure
before proceeding. Apply caulking directly in and over cracks using appropriate caulking gun.
COVERAGE RATE: 502MS Karna-Flex is typically applied in a 1/16” to 1/8” thickness depending upon
the substrate which equates to a coverage rate of 4 to 8 gallons per 100 sq. ft. When sealing cracks
and joints apply in two applications with fabric reinforcement.
Coverage Rates with Fabric Reinforcement: Approximate
Fabric Width
4"
6"
If Mastic Applied at 1/16" thick, two applications (Lineal Feet per Gallon)
25'
18'
If Mastic Applied at 1/8" thick, two applications (Lineal Feet per Gallon)
12'
9'
Fastener Coverage:
Place a dollop (swirl coat) over exposed fasteners. Approximate coverage rate is 250 fasters per gallon
Caulking Cartridge:
A 1/4" x 1/4" bead will yield approximately 75 lineal feet per 30-oz. cartridge.
CAUTION: Do not use near open flame. Avoid breathing solvent fumes and prolonged contact with
skin. Do not take internally. If swallowed, do not induce vomiting. Call a physician immediately. Keep
out of reach of children. Coating must be dried before exposure to water. Store in a heated room and
keep container covered when not in use. Do not thin. Dispose of in an environmentally safe manner.
Cover air intakes during application and while drying. For exterior use only.
Cold-process systems and coatings, either emulsion or solvent-based, should only be installed on decks with positive drainage. Per NRCA (National
Roofing Contractors Association), “The criteria for judging proper slope for drainage is that there be no evidence of standing water on a deck 48 hours
after it stops raining.”
NOTE: 502MS Karna-Flex White is not recommended for use over asphaltic substrates due to the likelihood of asphalt bleed through. For this reason,
502MS Karna-Flex Black is recommended over these types of substrates. PVC and TPO roofs should at least be 4 years old before using this product.
PACKAGING: Available in 3-gallon buckets, 30-oz. caulking cartridges (White Only)
If further information is needed, contact KARNAK Technical services at 800-526-4236.
PHYSICAL PROPERTIES &
SPECIFICATIONS
Weight per Gallon: 9.48 lbs.
Solids by Weight: 66%, Nominal
Solids by Volume: 57%, Nominal
Color: White, Black, Gray
Elongation: 913%, Nominal
ASTM D 412
Tensile Strength: 168 PSI, Nominal
ASTM D412
Reflectance: 83%
ASTM D 2824 (White)
Accelerated
Weathering: Pass/No Cracks -
ASTM G155 after 1,000
hrs.
Firm Set: Pass – ASTM D 2939
Resistance to
Water: Pass – ASTM D2939
Firm Set: Pass – ASTM D 2939
24 hours@ 77°F and
50% Relative Humidity
Application Temp.: 40°F to 120°F
Service Temp
(Cured Film): -15°F to 180°F
VOC Content: <490 g/L MAX
Tested in compliance with FBC (HVHZ)
TAS 139