Category Archives: Materials Testing

Climbing Drum Peel Test for Adhesives

By Bruce Niederer

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

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

Low-Tech Adhesion Testing

By Jim Derck

Before beginning a project, it’s a good idea to test the adhesion between epoxy and the materials to be used. Preliminary adhesion tests can help you choose the best materials and surface preparation methods. It can also help to avoid a surprise bonding failure.
At Gougeon Brothers, Inc. we use a Pneumatic Adhesion Tensile Testing Instrument (PATTI) for adhesion tests. After the PATTI test stud is bonded to the test surface, the stud is pulled in tension until it releases. The instrument gauge gives a precise pounds per square inch reading at failure. Continue reading

Minimizing Amine Blush

By Tom Pawlak with Tim Atkinson

I recently built a double-ended paddle for my kayak. The blades were made of thin mahogany plywood coated with epoxy. I had coated all the paddle parts with two coats of epoxy the day before, and overnight a thin oil-like film had formed on the surface of the epoxy. This is amine blush. To ensure a good bond between the blade and the shaft, I removed the blush with water, dulled the surface with an abrasive pad, and dried the surface with paper towels. I’m confident using my new kayak paddle because the mating surfaces of the shaft and blade were properly prepared prior to bonding. Continue reading

Bonding PVC Plastic with Epoxy

Editor’s note: This article was originally written in 1994, long before we developed G/flex epoxies which offer vastly superior performance in bonding to plastics including PVC. A much more current article on this subject is Gluing Plastic with G/flex Epoxy by Tom Pawlak and Jeff Wright. If you’re interested in gluing PVC with epoxy, we suggest you start there. The following article is published at Epoxyworks.com for historical purposes only.

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Cold Temperature Bonding & Coating with Epoxy

Strategies for successful application and curing of epoxy at low temperatures

Epoxy behaves differently in cold temperatures. These handling tips can guide you in obtaining optimum performance from epoxy in this fall and winter.

Epoxies reach a higher percentage of their potential physical properties when mixed and applied at temperatures above 60°F. However, you can use epoxy at lower temperatures and still obtain a dependable bond. The key is adapting your handling and application techniques to cold temperatures. Whether you live in a Northern or Southern climate, it is helpful to know how temperature affects epoxy chemistry, how epoxy handles differently in cold conditions, and what steps you can take to assure dependable bonds in cold weather. Continue reading