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G/Flex 650-K Aluminum Boat Repair Kit


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Model # 9223140 | Mfg # 650-K

Product Description

G/flex 650 is a new epoxy introduced by WEST SYSTEM in mid-June 2007. A toughened, versatile, liquid epoxy for permanent waterproof bonding of fiberglass, ceramics, metals, plastics, damp and difficult-to-bond woods. G/flex offers these important features:

  • Toughness and Flexibility G/flex has been toughened. This gives G/flex the ability to make structural bonds that can absorb the stresses of expansion, contraction, shock, and vibration. G/flex is resilient and impact resistant. With a modulus of elasticity of 150,000 psi (WEST SYSTEM 105 Resin/205 Hardener has a modulus of elasticity of 450,000 psi), G/flex is more flexible and can deflect further than WEST SYSTEM 105/205, while being much stiffer than typical adhesive sealants.
  • Bonds to wet and damp surfaces G/flex has the ability to glue damp woods. It can be used on wet surfaces, even underwater when applied with specific techniques.
  • Excellent adhesion to hard-to-bond woods G/flex adheres tenaciously to difficult-to-glue hardwoods, both tropical and domestic varieties. This is important since many of the exotic and tropical species now being used to replace traditional woods present bonding challenges.
  • Bonds well to a variety of materials G/flex is ideal for bonding a variety of materials, including dissimilar ones. G/flex has a superior grip so that it can be used to bond to 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.
  • Ease of use G/flex is a simple two-part epoxy system. Resin and hardener are mixed in a 1:1 mix ratio by volume. For added convenience, a pre-thickened version, G/flex 655 Thickened Epoxy Adhesive, is also available. G/flex provides a relatively long open working time of 45 minutes. It cures in 7-10 hours and can be used in cool temperatures. Because it is simple to mix and use, G/flex is an excellent starting point for customers new to epoxy use.
  • Versatility G/flex can be modified with WEST SYSTEM fillers and additives if you need to meet particular bonding needs. Adding G/flex to other WEST SYSTEM epoxies can improve their toughness and flexibility.


G/Flex 650-K Aluminum Boat Repair Kit

Best Use Kit Contains Epoxy
Mixing Components
Filler and More
Capacity 8 Ounces
Cure Time 7 to 10 Hours (Working time: 45 Minutes)
Type Two-Part Epoxy Resin

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by PowerReviews
West System G/Flex 650-K Aluminum Boat Repair Kit

(based on 1 review)

Ratings Distribution

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  • 1 Stars



Reviewed by 1 customer

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(18 of 20 customers found this review helpful)


Excellent results after multiple trials

By Triton Jason

from Sandusky, OH

Verified Reviewer


  • Cheap Cost
  • very durable


  • Difficult to use
  • Very messy

Best Uses

  • Any Aluminum Boat Repair

Comments about West System G/Flex 650-K Aluminum Boat Repair Kit:

I have beat my boat so bad on Lake Erie that I had five cracks on the corner break where the hull bends down to the transom two days before the first spring walleye tournament. I bought the G/flex 650k hoping to fix the cracks that I had that were starting to cause my bilge to run nearly continuously because there was no way I could get it welded with tournament season just getting ready to start. After hours of trial and error trying to patch the bottom side of the boat, I found that I had to mix in enough hardener to make a very, very thick paste as I mixed this product. After several unsuccessful attempts to keep it from dripping down on me as it set up even as paste-like as it was, I found that I had to let the mixed up epoxy sit in the mixing bowl for roughly a half hour before applying it. Also temperature control of 60 to 70 degrees in my garage seems to work best. I have run my boat as hard as ever since early spring when I first patched those holes with no further issues arising where I had patched it. In the final tournament this fall, I also cracked the main weld on the keel of the boat roughly 14" in length and that was a severe crack that almost sunk us before we made it back to the ramp. I also patched that crack with the same kit of G/Flex 650k and have had the boat airborne in 3 to 4 footers for long runs a few times since to test it out and it seems to be holding up just as well as the smaller cracks in the panels have all season long. This stuff is very messy and hard to work with but it really is a cheap alternative versus having someone disassemble the boat to weld it up from the inside behind the foam. I have considered coating the whole hull of my boat with this stuff as it seems to be more durable than the .100" thick panels are.

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