G/flex Epoxies are toughened, resilient two-part epoxies engineered for a superior grip to
metals, plastics, glass, masonry, fiberglass, and wet and difficult-to-bond woods. G/flex
Epoxies are available in two consistencies. G/flex 650 Epoxy is a liquid epoxy with a honey-
like consistency. G/flex 655 Epoxy Adhesive is pre-thickened with a consistency similar to
gel toothpaste. Both have an easy-to-use 1:1 mix ratio. G/flex provides a relatively long
open working time, yet it cures quickly and can be used in cool temperatures.
G/flex Epoxies are toughened to make them resilient and impact resistant, giving them the
ability to make structural bonds that can absorb the stresses of expansion, contraction,
shock, and vibration. With a modulus of elasticity of 150,000 psi, G/flex is more flexible
and can deflect further before breaking than WEST SYSTEM 105/205, while being much
stiffer than typical adhesive sealants.
G/flex adheres tenaciously to difficult-to-glue hardwoods, both tropical and domestic
varieties. It can be used to bond metals, plastics, glass, masonry, and fiberglass. G/flex is
ideal for repairs to aluminum boats and polyethylene and ABS canoes and kayaks. It can
also be used to wet out and bond fiberglass tapes and fabrics. G/flex 650 can be modified
with WEST SYSTEM fillers and additives and added to other WEST SYSTEM epoxies to
improve their toughness and flexibility.
Mix ratio by volume ……………………………………………………………………………………. 1:1
by weight ……………………………………………………………………………………….. 1.2:1
Mix viscosity G/flex 650 (at 72 F) ASTM D-2393 ……………………………….. 15,000 cps
G/flex 655 …………………………………………………………………………………………. gel
Pot life (100g at 72 F) ………………………………………………………………………. 45 minutes
Working time ………………………………………………………………………………….. 75 minutes
Initial cure …………………………………………………………………………………….. 3 to 4 hours
Workable cure* ……………………………………………………………………………. 7 to 10 hours
Minimum recommended temperature ………………………………………………… 40 F (4 C)
*Wait 24 hours before subjecting to high loads.
Specific gravity …………………………………………………………………………………………. 1.11
Hardness (Shore D) ASTM D-2240 ……………………………………………………………….. 75
Compression yield ASTM D-695 …………………………………………………………..5,270 psi
Tensile strength ASTM D638 ……………………………………………………………….3,440 psi
Tensile elongation ASTM D-638 ……………………………………………………………… 32.7%
Tensile modulus ASTM D-638 ……………………………………………………… 1.44E+05 psi
Flexural strength ASTM D-790 …………………………………………………………….5,190 psi
Flexural modulus ASTM D-790 …………………………………………………………..1.56E+05
Heat deflection temperature ASTM D-648…………………………………………………. 127 F
Onset of Tg by DSC ………………………………………………………………………………… 138 F
Ultimate Tg ……………………………………………………………………………………………. 154 F
Store at room temperature. Keep containers sealed when not in use to prevent
contamination. With proper storage, resin and hardener should remain usable for several
years.