Please select your home edition
Edition
Wessex Resins 2019 - Pro-Set - 728x90

Wessex Resins & Adhesives product of the month: G/flex 650 Epoxy

by Jake Kavanagh 28 Dec 2018 09:00 GMT
The G/flex range is available in several sizes and in two different types, thickened (655) and unthickened (650) - Six10 is gap-filling adhesive that self-mixes in the nozzle © WSI

What is it? G/flex 650 Epoxy is described as a 'toughened, resilient two-part epoxy engineered for a superior grip to metals, plastics, glass, masonry, fibreglass and wet and difficult-to-bond woods.'

Used for? Basically, all those difficult jobs, the bonds most likely to fail after using standard DIY adhesives. Typical examples would be where there are going to be stresses from expansion, contraction, shock or vibration. It is also good for bonding different density materials that are traditionally hard to glue together. These include attaching the PVC tubes of an inflatable to a GRP transom, or closed cell foam insulation to a curved bulkhead. If the job is a tricky one, G/flex 650 or the thickened 655 is most likely to be the answer.

Mixing ratio? A very simple 1:1 mix ratio by volume, or 1.2 parts of resin to 1 part hardener by weight. This will give a pot life of 45 minutes and a long 'open' time of 75 minutes at room temperature. The initial cure is reached in 3-4 hours, with a workable cure in 7-10 hours depending on the temperature. Getting the ratios spot on will ensure the most effective bond.

Hamish's tips

"G/flex 650 is available in two distinct types, 650 Epoxy and the pre-thickened 655 Epoxy Adhesive. Both will produce a really strong bond, even to exotic materials. As the name suggests, the bond will tolerate a lot of flexing."

Use 650 for fabrics and metals

"The G/flex range was developed by the Gougeon Brothers to tackle some of the most difficult bonding challenges. The standard 650 Epoxy is a liquid resin and hardener, to which you can mix some additives such as colloidal silica if necessary. In its unaltered state, G/flex 650 Epoxy is excellent at bonding fabrics such as kevlar,carbon fibre and aramids to substrates like GRP, polypropylene or glass. (If the driving mirror in your car has fallen off the windscreen, reach for the G/flex). It is often used to add reinforcing pads to the inside of white water canoes, as it flexes easily when the canoe hits a rock, or is twisted by powerful currents."

Hamish also says that G/flex 650 was designed to tackle a very American problem, opening seams in metal boats.

"The US has vast numbers of aluminium boats, which are builtusing rivets. As the hulls wear the rivets work loose and water can get in. G/flex 650 is perfect for injecting into the rivet holes or along opening seams, to make a flexible watertight seal. The treatment also helps prevent any further degradation."

Use 655 Epoxy Adhesive for mainstream bonding

"The 655 version is G/flex 650 thickened to make it more useful for bonding applications," Hamish says. "Typical uses would be on foams, wood to glass, or any job where a thicker adhesive will produce better results. We know lots of people who have used it to successfully bond the soles of their work boots back on, as the cured epoxy can move with the rubber and leather."

The flexibility of the cured product is what makes it so versatile.

"The cured product is really robust," Hamish says. "You can hit it repeatedly with a hammer and it won't shatter. Check out the YouTube video of a canoe being cut in half and then bonded back together using G/flex 655. It is back in action the very next day and as strong as it was before."

A typical bonding job

A 25mm high density closed-cell foam needs to be bonded to a GRP minor partition. The GRP has been prepared with cleaning and abrasive sanding.

G/flex 650 Epoxy, it is a liquid but can be thickened with 406 Colloidal Silica additive for a thickened glue. However, this consistency is adequate for our needs.

The epoxy allows the foam to be quite easily moved around on the substrate and the 75 minutes of 'open' (workable) time allows for plenty of repositioning and adjustment.

As a little bit is left over, it is used to repair a set of old car keys where the metal shank has come adrift from its plastic keeper. If you are unsure of the quantities you need, then having a couple of other jobs ready means that nothing is wasted.

(Eagle-eyed readers will note that this is a larger partition and one we made earlier).

Unlike impact or 'contact' adhesives, this will not be affected by temperature. Some impact glues, especially those that get used for jobs in an engine-rooms, can loosen in excessive heat but the 650 will remain rock solid.

G/flex information: westsysteminternational.com/en/west-system/west-system-g-flex-epoxy

Related Articles

Stunning colour tints for epoxy creations released
An exciting line of liquid colours has been released to add bold and beautiful tints to epoxy Specifically designed for epoxy river tables, jewellery and other crafts as well as sporting equipment like surf, skate and snowboards, the beautiful selection of colours come in two thematic packs, Soft and Vivid. Posted on 1 Aug
DNV GL approval for Pro-Set epoxies
Lloyd's Register approval for WS resin and hardener combination PRO-SET epoxy systems have been approved by DNV GL for use on ships, yachts and as 'laminating resin for construction of laminates made of fibre reinforced plastics'. Posted on 14 Jul
Building a wooden dinghy with epoxy resin part 3
Completing the hull and making an amazing spinnaker chute Steve Goodchild wanted to avoid nailing the planks to offset chocks set against the frames, as this would leave multiple rows of nail holes visible in the wood. Instead, he decided to glue the entire hull together using thickened epoxy. Posted on 11 Jun
Chandleries currently open stocking epoxy resin
Places to buy West System products during June 2020 in the UK We're all eagerly anticipating the reopening of retail outlets. In the meantime, if you're looking to stock up on your favourite epoxy brands, here are some WEST SYSTEM®, PRO-SET® and Entropy Resins® epoxy stockists who we know are currently open. Posted on 5 Jun
WEST SYSTEM® epoxy set to go sub-orbital
NOVA 2 rocket within ten months of its first launch A NOVA 2 rocket being developed by Starchaser is within ten months of its first launch. This one-seater rocket is a significant step towards future plans which include a rocket capable of taking two passengers with the pilot. Posted on 1 Jun
West System used to create bullet coat racks
New lockdown project using epoxy resin Dee (David) Caldwell has spent his lockdown creating bullet coat racks. Using locally sourced WW2 bullets he's collected at Medmerry, West Sussex, and wood from a cedar planted by Capability Brown, he's started a new business in his garden workshop. Posted on 13 May
Electric boat's sustainable construction
Bio-based infused epoxy resin, recycled PET, and basalt/flax fibres RS Electric Boats, the sister company to RS Sailing, unveiled its electric RIB earlier this year, a boat that's said to be the highest level of sustainable construction of any boat in its sector. Posted on 2 May
WEST SYSTEM 105-K Glass Fibre Boat Repair Kit
The upgraded kit comprises everything needed to fix minor cracks, holes and punctures Wessex Resins is delighted to announce it has improved and updated the WEST SYSTEM® 105-K Glass Fibre Boat Repair Kit. The kit comprises everything needed to fix minor cracks, holes and punctures as well as refit and replace hardware on a boat. Posted on 16 Apr
Wessex Resins & Adhesives joins 1% for the Planet
Donating to Protect Our Winters UK Wessex Resins and Adhesives is delighted to announce it has donated 1 per cent of its annual turnover for the ENTROPY RESINS® product range to Protect Our Winters UK. Posted on 9 Apr
Building a wooden dinghy with epoxy resin part 2
Strip planking the hull, and making an amazing wooden mast "You don't build your own boat to save money," Steve explains. "You do it for the sheer satisfaction of the craftsmanship involved. For what I paid in raw materials I could have bought several second-hand boats, but where is the fun in that?" Posted on 18 Mar