Tag Archives: adhesion

Understanding Flexible Properties

By Jeff Wright

The Technical Staff at Gougeon Brothers, Inc. regularly discuss 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.

For the kayak paddle, the customer’s concern is that the epoxy will allow the stiff carbon fiber fabric to be as rigid as possible. For bonding the unstable wood, the Continue reading

Borate Salt Treats Decayed Wood

By Tom Pawlak

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 attack. 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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Effect of Surface Treatment on Adhesion to Metals

By Brian Knight

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.

All the tests shown below were performed using a PATTI (pneumatic adhesive tensile test instrument) meter. We chose this test method as our default adhesion Continue reading

Woods of the World Adhesion Testing

By Tom Pawlak

We recently purchased a 154-piece wood sampler from Eisenbrand Inc., Torrance, California. The 3″ × 6″ × ½” specimens originated from points all around the world. Each specimen was provided with its common name, scientific name, and country of origin. There were several specimens we’ve never heard of.

The PATTI test uses compressed air to pull the stud from the surface. It records the force required to break the bond in pounds per square inch. In all cases tested, the epoxy held and the wood failed. Continue reading

Epoxy Adhesion Over Stains

By Tom Pawlak

We have occasionally reported results of adhesion testing of WEST SYSTEM® epoxy to wood coated with various stains. In Varnish Over Epoxy (Epoxyworks 18), we touched on the topic of wood stains under epoxy and warned that some oil-based stains would cause an adhesion problem for WEST SYSTEM epoxy. Since then, we have done some additional adhesion testing to a number of stains. Continue reading

Adding Pigments to Epoxy

By Bruce Niederer

We often get asked ‘What can I use to color my epoxy?’ The intended application is as varied as our customers. Often it’s simply to make it easier to paint over or to provide a color indicator between layers. Sometimes it’s to match a particular colored material in a repair. Maybe it’s for an art or craft project. The point is, people are often looking for a color other than the black 423 Graphite, 501 White or 503 Gray Pigments offered in the WEST SYSTEM® product line. What are some options? And what are the pigment’s effects on the performance of the epoxy? Continue reading

Preparing a fiberglass laminate

A Better Way to Prepare Laminates

By Tom Pawlak

During a recent inspirational hardware store visit, I discovered a rotary wire brush made by Norton™ called the Rapid Strip Brush™. It is used with an electric drill and produces results comparable to bead blasting or a needle scaler. The package says it can be used to abrade metal, masonry and fiberglass. I immediately thought of a fiberglass application that I wanted to try it on. Continue reading

Avoiding Surface Contamination

By Brian Knight

“Cleanliness is next to Godliness” the old expression goes. This is certainly true when preparing a surface for an epoxy application. The surface has to be clean to begin with or there may be adhesion problems. But often, our good intentions with respect to cleaning a surface result in contaminates deposited on the surface. Below are some potential surface contaminates, ways to avoid them, and an almost foolproof method to determine if a surface is clean or contaminated. Continue reading

Testing DCPD Blend Laminates

By Tom Pawlak

Gougeon Brothers recently did R&D testing for a manufacturer who wanted to know if WEST SYSTEM® epoxy could effectively repair injection-molded parts made with fiberglass and dicyclopentadiene (DCPD) blended polyester resin that included an internal mold release. The hoods and decks for many jet skis and snowmobiles are made with this material.

DCPD blends in polyester cause it to cure rapidly and cross-link thoroughly. This feature helps to reduce emissions from the resin but makes it difficult to repair Continue reading

Protective skin creams-do they affect adhesion to the surfaces we touch?

By Tom Pawlak

We recently completed adhesion testing for a boatbuilder who was concerned about surfaces being contaminated by workers who use protective skin creams. The builder wanted to be sure that residue from the protective creams did not contaminate objects touched by workers throughout the day. We tested five products: Derma Shield™, Gloves in a Bottle™, Unique Skin™, SBS 46 Protective Cream™ and SBS 40 Medicated Skin Cream™. Continue reading