Category Archives: Epoxy Products

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

decayed wood on a small boat

Borate Salt Treats Decayed Wood

by Tom Pawlak — GBI Technical Advisor

Above: Decayed wood on a small boat. Photo by Chester Ho on Unsplash 

Sodium borate is used in a number of commonly used household products from laundry detergent to hand soap. It is also used to treat wood against insect and fungal attacks. Sodium borate is refined from borax, a natural mineral, which is mined throughout the world. One of the largest deposits is in the Southwestern United States. (Think 20-Mule Team Borax™, Death Valley Days radio and TV shows).
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Comparing Cost and Weight of Flat Panels

How to choose the best materials when building flat panels

by Jeff Wright — Vice President of Technical Services

Above: Jeff Wright, Vice President of GBI Technical Services, poised to take a deep dive into types, materials, costs, weight, and stiffness of flat panels.

Many WEST SYSTEM® customers appreciate the benefits of cored composite construction. They understand that it creates a part that is lightweight, strong, and stiff. We often receive calls from these customers inquiring about using a composite panel when building or repairing something that would normally be made of plywood. Such projects may include a new center console for a fishing boat or the replacement of flying bridge side shields. Determining the best material requires consideration of many aspects of the project, but often comes down to cost versus weight. Continue reading

Epoxy's adhesion to metal is affected by surface treatment

Effects of Surface Treatment

On Epoxy Adhesion to Metals

by Brian Knight—GBI Technical Advisor

Above: Surface treatment can make all the difference in epoxy adhesion to metal. Photo by Manny Becerra on Unsplash 

We have performed tens of thousands of adhesion tests over the years and many of these tests were done on metal surfaces. Below is a summary of tests done on a variety of metal surfaces and done with a variety of surface preparations. As you look at the chart, notice the surface preparation that gives the highest number.

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Epoxy vs. Polyester is an important consideration in fiberglass boat repair.

WEST SYSTEM Epoxy vs. Polyester

for Fiberglass Boat Repair

by Tom Pawlak — GBI Technical Advisor

Above: Epoxy vs. polyester in a typical fiberglass boat repair cross-section. 

Even though we’ve been promoting the use of WEST SYSTEM® Epoxy for repairing fiberglass boats (boats made with polyester resin) in our manuals and Epoxyworks for many years, we continue to receive inquiries asking whether it is appropriate to use epoxy for polyester boat repair. Because of the misinformation still prevalent in marinas, local yacht clubs and on the Internet, we felt it was time to restate the case for epoxy. Continue reading

Chopped Strand Mat

Chopped Strand Mat and Epoxy

by Tom Pawlak — GBI Technical Advisor

Above: Wet-out chopped strand mat and woven fabric test samples are prepared for moisture uptake testing.

Chopped strand mat, in fabric form, is sold on the roll and in small folded packages. It is made up of 1″-2″ long fiberglass strands that are randomly oriented and typically held together with a styrene-soluble binder that acts like glue connecting the fibers. The binder is designed to dissolve upon contact with styrene in polyester resin or vinylester resin. Once dissolved, the fabric softens, allowing it to drape around curved shapes. It comes in a variety of weights between .75 oz to 3 oz per square foot. The most popular weights are .75 oz and 1.5 oz. Continue reading

G/5 Adhesive Tips

Working with G/5 Resin & Hardener

By Tom Pawlak — GBI Technical Advisor

Above: To simplify mixing G/5 Resin and Hardener for a large project, Grant made a carrying pallet with sixteen holes, sized to hold 1-ounce mixing cups (pill cups purchased at a food service outlet). The pallet was covered with duct tape so glue drips could be peeled away. Note that a mini cupcake pan could be dedicated to this kind of task as well.

Many of us at Gougeon Brothers experiment with WEST SYSTEM® products on personal projects at home as well as at work. We often push products and techniques beyond the limits recommended in our literature. Sometimes the experiment fails, sometimes we discover something very useful. Continue reading

Scheherazade under sail.

Testing Large Bonded-In Fasteners

by Brian Knight—GBI Technical Advisor

Above: Scheherazade, the 154’7″ yacht that required testing of large bonded-in fasteners.

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Cover Photo: The 154’7″ Bruce King-designed Scheherazade resting on her massive keel at Hodgdon Yachts in East Boothbay, Maine.

Scheherazade is a 154′ 7″ Bruce King-designed ketch under construction at Hodgdon Yachts, in East Boothbay, Maine. Scheherazade is 60% larger than Antonisa, the last Bruce King/Hodgdon Yacht collaboration, and is the largest sailboat under construction in the United States. Continue reading

estimating epoxy amounts for fiberglassing

Estimating Epoxy Amounts

By Bruce Niederer — GBI Technical Advisor

Above: The layout of an Optimist pram provides an example of how to go about estimating epoxy amounts.

This formula will help you estimate the amount of mixed epoxy needed to wet out fiberglass cloth (assuming a resin-to-fiber ratio of 50:50) and apply three rolled epoxy coats to fill the weave of the cloth, i.e. “fill coats.” Continue reading