Category Archives: Materials Testing

Porch Railing Coating Analysis

By Tom Pawlak — GBI Technical Advisor

My porch railing at home was badly in need of painting even though I had painted it the summer before. After just one Michigan winter, the paint had cracked and lifted. I wondered to myself if coating the top rail with WEST SYSTEM® epoxy would improve this poor situation and decided to turn the top rail into a small R & D project. Continue reading

GBI test lab

The Versatility of Epoxy

By Rob Monroe

From ice boats to racing multihulls, wind turbine blades, and a thousand other projects — ours and customers — working with epoxies and our customers since 1969 has been interesting. The decades of experience in the shops, labs and libraries have given us a pretty good feeling for epoxy technology. We know its strengths and weaknesses, and most importantly we understand and appreciate its versatility.

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Hardware Bonding

By Tom Pawlak — GBI Technical Advisor

My first experience with hardware bonding occurred shortly after starting work at Gougeon Brothers in 1980. Having just been hired into the wind turbine blade plant, I was excited to be part of this interesting company. Continue reading

fastener load path

More on Hardware Bonding

General considerations for epoxy bonded fasteners in wood

By Robert Monroe

With epoxy bonded fasteners, the idea is to balance the three parts, (fastener, epoxy and wood/hole) to obtain optimum performance. The key information needed is the tensile strength of the fastener, the shear strength of the epoxy and the withdrawal resistance of the wood or backing block. Continue reading

Panel Warping

By Tom Pawlak — GBI Technical Advisor

CAUTION: Strip planked projects can warp to the point of being unusable if one side of the wood core is fiberglassed and the other side is left unsealed. Changes in wood moisture content on the unsealed side will cause the project to change shape. The potential for warping is greatest on thin wood-strip projects like canoes and kayaks. The thinner the planking, the greater the risk. Continue reading

Climbing Drum Peel Test for Adhesives

By Bruce Niederer — GBI Technical Advisor

No matter how you use WEST SYSTEM epoxies, you expect us to back up the products and methods we recommend with solid data based on tests that simulate “real life” applications. To this end we began conducting the ASTM 1781-93 test method known as the Climbing Drum Peel for Adhesives. As expected, the results from this test method compliment the data we’ve already compiled using the PATTI (Pneumatic Adhesion Tensile Testing Instrument) meter. Continue reading

Effects of Cool Temperature on Adhesion

By Captain James R. Watson

Many shops are heated only while working on the project. Often a bonding application is allowed to cure after the furnace is turned down and the shop cools off overnight. The question arises, does this temporary suppression of the cure affect adhesion. Continue reading

Assessing Material Strength for Small Parts

By Captain James R. Watson

The appropriate laminate thickness for a particular application is difficult to come up with out of the blue. We have a “feel” for how strong something must be to suit our purposes. Our hands are fairly sensitive for detecting slight load increases, up to about 30 pounds. We can use them to evaluate a variety of materials. The only problem is, we don’t know the numerical equivalent of the pressure we’re applying. Continue reading

primer performance

House Paint Primer Performance

By Tom Pawlak — GBI Technical Advisor

In the past, we’ve recommended applying an alkyd base primer over well-cured, clean, and sanded epoxy surfaces. We wanted to know how this primer compared to the newer, fast drying primers now available. We recently did a study of various house paint primers over epoxy to support the growing number of customers using WEST SYSTEM epoxy for building restoration. Continue reading