Category Archives: Techniques & Tips

Comparing Cost and Weight of Flat Panels

By Jeff Wright — Vice President of Technical Services

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 →

Practical Uses for Razor Blades

By Tom Pawlak — GBI Technical Advisor

Necessity is the mother of invention, and razor blades are often called into service for a variety of tasks around the shop other than shaving. Here are a few.

MINI-SPREADER

Razor blades can be used in a pinch to apply caulks and thickened epoxies with great precision. They do a great job filling isolated pinholes and scratches, especially when the blade is laid at a low angle (nearly flat) when spreading the putty. Continue reading →

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 →

WEST SYSTEM Epoxy vs. Polyester for Fiberglass Boat Repair

By Tom Pawlak — GBI Technical Advisor

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 Over Epoxy

By Jeff Wright — Vice President of Technical Services

Most production fiberglass boats are made with polyester resin. 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 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.

GBI’s testing is an important part of its customer support. Often it is prompted by specific questions or requests from customers. As discussed here, fatigue tests of various composite Continue reading →

Building for Long-Term Competitive Performance

By Bram Dally

Swift Solo, a single handed skiff built by Bram Dally.

When Meade Gougeon asked me if I’d write a piece about what I’m up to for Epoxyworks, I was honored. He had read the January 2002 article on my single-handed skiff in Sailing World and offered the assistance of GBI (Gougeon Brothers, Inc.) to do some extensive testing for us on several composite samples. The findings will be made public and should be educational. The cedar-cored samples particularly interest me because we’ve had good success using cedar cores and there seems to be a pervasive lack of understanding regarding this composite in high-tech applications. While many high-quality ski and snowboard manufacturers have tried other exotic Continue reading →

Woods of the World Adhesion Testing

By Tom Pawlak — GBI Technical Advisor

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 →

Chopped Strand Mat and Epoxy

By Tom Pawlak — GBI Technical Advisor

Chopped strand mat, in fabric form, is sold on the roll and in small folded packages. It is made up of 1″-2″ long fiberglass strands that are randomly oriented and typically held together with a styrene-soluble binder that acts like glue connecting the fibers. The binder is designed to dissolve upon contact with styrene in polyester resin or vinylester resin. Once dissolved, the fabric softens, allowing it to drape around curved shapes. It comes in a variety Continue reading →

Epoxy Adhesion Over Stains

By Tom Pawlak — GBI Technical Advisor

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 →