Tag Archives: adhesion

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 →

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).
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.

Continue reading →

Epoxy’s Adhesion to Wood

Woods of the World Epoxy Adhesion Testing

by Tom Pawlak — GBI Technical Advisor

Above: Epoxy’s adhesion to wood is the focus of this study of dozens of wood varieties from Africa and the Philippines.

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’d never heard of in this study of epoxy’s adhesion to wood. Continue reading →

Epoxy Adhesion Over Stains

by Tom Pawlak — GBI Technical Advisor

Above: Testing of epoxy adhesion over stains was done with a number of different stains.

We have occasionally reported results of adhesion testing of WEST SYSTEM® epoxy to wood coated with various stains. In “Varnish Over Epoxy,” 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 of epoxy over a number of stains. Continue reading →

adding pigments to epoxy

Adding Pigments to Epoxy

by Bruce Niederer — GBI Technical Advisor

Above: Our study of adding pigments to epoxy.

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 for adding pigments to epoxy? And what are the pigment’s effects on the performance of the epoxy? Continue reading →

A great tool when you want to prepare fiberglass laminates for epoxy adhesion

A Better Way to Prepare Fiberglass Laminates

by Tom Pawlak — GBI Technical Advisor

Above: The Rapid Strip Brush™ is a great tool when you want to prepare fiberglass laminates for epoxy adhesion.

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 →

Bonding surfaces should be as dry as possible.

Avoiding Surface Contamination

For Good Adhesion

by Brian Knight—GBI Technical Advisor

Above: Sanding the bonding surface is important to good adhesion with epoxy.

“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 — GBI Technical Advisor

Above: A DCPD blend laminate repaired with WEST SYSTEM Epoxy is tested to failure. The laminate required gross deformation before it failed, meaning epoxy is an appropriate repair material for the type of laminates common on jet skis and snowmobiles.

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

Continue reading →

protective skin creams

Protective Skin Creams

Do they interfere with adhesion?

Above: Protective skin creams. Photo by Nati Melnychuk on Unsplash

By Tom Pawlak — GBI Technical Advisor

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 →