Category Archives: Materials Testing

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 →

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 →

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 →

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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If You Can’t Take the Heat…

Understanding Epoxy and Heat Deflection Temperature

By Bruce Niederer — GBI Technical Advisor

Above: The test apparatus holds five of the test samples shown below in a bath of heated oil while a three-point load is applied to the sample. It is used to determine heat deflection under load (HDUL) temperature and the effects of high temperatures on cured epoxy.

Among both professionals and amateurs in the world of composites, there are certain enduring misconceptions and rumors regarding the effects of elevated temperature on an epoxy bond. Armed with just enough misinformation to be dangerous, folks will make important decisions that can lead to costly or time-consuming mistakes that might have been avoided—if they had an adequate understanding of the principles that encompass epoxy structures and temperature. By defining some commonly used terms and briefly discussing issues surrounding epoxy application, we hope to dispel some of these misconceptions about epoxy and heat.

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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 →

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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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 →

Polyester Gelcoat Over Epoxy

by Jeff Wright — Vice President of Technical Services

Most production fiberglass boats are made with polyester resin, and we’re often asked if it’s appropriate to use polyester gelcoat over epoxy. WEST SYSTEM® epoxy is a wonderful material for repairing polyester fiberglass boats. One reason for this is the ability of epoxy to form a stronger mechanical bond to a damaged laminate than polyester resin. Epoxy also provides a better moisture barrier than polyester resin. Continue reading →

There Will Be a Test

by Kay Harley

A research mentality and ongoing epoxy testing permeate all levels of Gougeon Brothers, Inc. We are committed to rigorous, long-term research on WEST SYSTEM products and their uses with other materials in wide-ranging applications. Studies include the basic chemistry involved, safety for users and the environment, formulation changes, product modifications such as adding pigments or UV additives, panel strength and stiffness with varying composite lay-ups, and the strengths of epoxy bonds, including hardware bonding. GBI commits capital investments to improve its testing capability and supports active ASTM involvement.

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