Category Archives: Techniques & Tips

This joint style in an edge-glued, 1/8" thick HDPE strip holds tight when deflected and is great for gluing plastics.

Gluing Plastics with G/flex Epoxy

by Tom Pawlak — GBI Technical Advisor &  Jeff Wright — Vice President of Technical Services

Above: This joint style in an edge-glued, 1/8″ thick HDPE plastic strip which holds tight when deflected and is a good choice when gluing plastics.

One of our goals for G/flex® was the ability to bond to a variety of plastics. This was an ambitious goal because plastics historically have been used as mold release surfaces for epoxy, allowing the epoxy to release from the plastic when cured. While developing G/flex, we tested adhesion to a number of plastics with a variety of surface prep methods. Continue reading →

D-Ring Pads and G/flex Epoxy

by Tom Pawlak — GBI Technical Advisor

New Possibilities for HDPE Boats

D-ring pads are often attached to flexible surfaces with urethane adhesives to gain load-carrying capacity where there otherwise wouldn’t be any. They are used on waterproof fabric cargo bags, heavy tarpaulins, and inflatable boats. They are also sometimes used on the decks of canoes and kayaks to hold cargo in place on long trips. D-rings are not typically used on polyethylene canoes and kayaks because the urethane glues are not recommended for use on HDPE (high-density polyethylene) plastic. We experimented with gluing D-ring pads with G/flex 655 Thickened Epoxy Adhesive to HDPE plastic with that end-use in mind. Continue reading →

Toughness of G/flex Epoxy

Fasteners Demonstrate G/Flex Toughness

by Randy Zajac

It all started when I got a tech call from somebody asking if WEST SYSTEM® 105/206 would accept a nail pounded into it, after it was cured, with no pilot hole. I confidently said that it would not work well and in most cases, it would fracture the epoxy. Just for fun, I went out in the shop and tried it because even though we all pretty much agreed it wouldn’t work, nobody had ever actually done it. Well, we were right—the nail caused a “brittle” failure. Continue reading →

Mixing G/Flex with Other WEST SYSTEM Epoxies

by Jeff Wright — Vice President of Technical Services

Above: Mixing G/flex with other WEST SYSTEM Epoxies increases the versatility of these epoxy systems.

WEST SYSTEM 105 Resin-based epoxy is a very versatile system. For years, experienced users have been mixing and blending the various product combinations in countless ways. For example, users may blend 205 Fast Hardener and 206 Slow Hardener to make a hardener with a modified cure speed. Different uses of 410 Microlight® Fairing Filler provide a further example. Many customers assume that the only use of 410 is to make a fairing compound—it is added to thicken epoxy to a peanut butter consistency to create a light, easily-sanded filler. Continue reading →

Moisture Exclusion Effectiveness (MEE)-comparison

Moisture Exclusion Effectiveness

by Bruce Niederer — GBI Technical Advisor

Above: A graph of moisture exclusion effectiveness.

I get mad at my computer fairly often these days when it takes more than a few seconds to open a file from an obscure site on the other side of the planet. Who has that kind of time to waste? Don’t even ask about photo files. There’s no point in arguing about it—we live in an accelerated world. We hate waiting for anything. Putting the social implications of this aside, a business involved in technical applications and products cannot afford to wait for real-time field test results. We need data and we need it yesterday! Continue reading →

WEST SYSTEM Launches G/Flex Epoxy

by Tom Pawlak — GBI Technical Advisor

G/flex Epoxy is a toughened, resilient two-part epoxy engineered for a superior grip to metals, plastics, glass, masonry, fiberglass, and wet and difficult-to-bond woods. Introduced in June 2007, G/flex Epoxy is currently available in two consistencies: G/flex 650 Epoxy, a liquid epoxy, and G/flex 655 Epoxy Adhesive, a pre-thickened epoxy. Both have a 1:1 mix ratio. Continue reading →

Understanding Flexible Properties

Epoxy Creep Stress, Flexibility, Strength, Stiffness, & Elongation

by Jeff Wright — Vice President of Technical Services

Above: The notched-beam test for creep stress determines flexible properties.

The Technical Staff at Gougeon Brothers, Inc. regularly discusses material properties in a variety of applications. For example, it is not uncommon for us to discuss with a customer how to use carbon fiber to stiffen a structure, such as the shaft of a kayak paddle, and then within minutes discuss with another how to bond a dimensionally unstable wood, such as oak, and ensure precautions are taken so that the relative movement of the wood will not cause a failure. Continue reading →

Positive displacement epoxy pumps

Tools for Measuring Epoxy Quantities

303 and 305 High-Capacity Positive Displacement Pumps

Above: Measuring epoxy is easier with positive displacement pumps.

For measuring epoxy accurately, Gougeon Brothers, Inc. has introduced high-volume epoxy pumps that are extremely robust. These pumps dispense epoxy faster than any pump the company has previously offered.  The 303 and 305 Positive Displacement Pumps work by trapping a fixed amount of resin and hardener, then forcing (displacing) that trapped volume into the discharge pipe or system.  The mechanics of this setup mean that increases in resin viscosity due to temperature changes will not slow dispensing speeds. Positive latching lids help prevent contamination of resins and hardeners.

The 305 Metering Pump is an excellent tool for measuring epoxy.

The 305 Metering Pump is an excellent tool for measuring epoxy.

The new 303 Positive Displacement Pump is calibrated for WEST SYSTEM 3:1 ratio epoxies (105 Resin with 207 Special Clear Hardener or 209 Extra Slow Hardener) and is easily identified with a red base. The new 305 Positive Displacement Pump is calibrated for 5:1 ratio epoxies (105 Resin with 205 Fast Hardener or 206 Slow Hardener) and has a blue base.

Positive Displacement Pumps are also available with drum fittings.  These connect directly to WEST SYSTEM Resin and Hardener drums so there is no need to decant materials.  This setup conveniently streamlines the metering process for high-volume users, saving both time and money.

Several manufacturers offer high-volume pumps that deliver epoxy at upwards of several gallons per minute. Several well-respected pump manufacturers are listed at the end of this article. Their pumps are specially designed to meter epoxy resin and hardener simultaneously at specific ratios. Some of these pumps can meter resin and hardener through a static mixer, so additional mixing isn’t required.

For more information on mixing larqe quantities of epoxy, read Tom Pawlak’s Big Batch Mixing Methods.

 

Accelerated Testing: Hot Soak Moisture Uptake

by Bruce Niederer — GBI Technical Advisor

Above: Batches of epoxy samples awaiting accelerated testing in the hot water bath.

We are constantly testing our products to fully understand and characterize them, and this is important both for ourselves and for our customers. A test method will usually produce results in a timely fashion, but there are times we must use an accelerated testing method so we can get the results before we take that last lonely boat ride across the river Styx. This article describes some of the accelerated testing we do here. Continue reading →

Citrus-based hand cleaner is great for removing uncured epoxy from your tools.

Removing Uncured Epoxy from Tools

by Glenn House — Director of Product Safety and Regulatory Compliance

Above: Safely removing uncured epoxy from your tools starts with a citrus-based hand cleaner. Photo by Mariya on Unsplash 

Removing uncured epoxy from tools used for applying epoxy often involves solvents that have strong odors and are flammable. A WEST SYSTEM® user suggested an alternative that does not have these problems: a solution of citrus-based hand cleaner and water. This solution will remove uncured epoxy from tools and can remove epoxy that has started to gel if the tools are allowed to soak for a few hours.
Continue reading →