Category Archives: Techniques & Tips

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.

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G/5 Adhesive Tips

Working with G/5 Resin & Hardener

By Tom Pawlak — GBI Technical Advisor

Above: To simplify mixing G/5 Resin and Hardener for a large project, Grant made a carrying pallet with sixteen holes, sized to hold 1-ounce mixing cups (pill cups purchased at a food service outlet). The pallet was covered with duct tape so glue drips could be peeled away. Note that a mini cupcake pan could be dedicated to this kind of task as well.

Many of us at Gougeon Brothers experiment with WEST SYSTEM® products on personal projects at home as well as at work. We often push products and techniques beyond the limits recommended in our literature. Sometimes the experiment fails, sometimes we discover something very useful. Continue reading

Scheherazade under sail.

Testing Large Bonded-In Fasteners

by Brian Knight—GBI Technical Advisor

Above: Scheherazade, the 154’7″ yacht that required testing of large bonded-in fasteners.

Epoxyworks 19

Cover Photo: The 154’7″ Bruce King-designed Scheherazade resting on her massive keel at Hodgdon Yachts in East Boothbay, Maine.

Scheherazade is a 154′ 7″ Bruce King-designed ketch under construction at Hodgdon Yachts, in East Boothbay, Maine. Scheherazade is 60% larger than Antonisa, the last Bruce King/Hodgdon Yacht collaboration, and is the largest sailboat under construction in the United States. 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

The putty knife scraper used as a push scraper.

Scrapers—Versatile Tools for Working with Epoxy

By Tom Pawlak — GBI Technical Advisor
Above: A putty knife scraper is being used as a push scraper.

My first experience with cabinet scrapers occurred shortly after hiring into Gougeon Brothers. Bill Slaby, a wood/epoxy technician who specialized in mold building, routinely used cabinet scrapers to remove irregularities on cured epoxy coatings. Continue reading

estimating epoxy amounts for fiberglassing

Estimating Epoxy Amounts

By Bruce Niederer — GBI Technical Advisor

Above: The layout of an Optimist pram provides an example of how to go about estimating epoxy amounts.

This formula will help you estimate the amount of mixed epoxy needed to wet out fiberglass cloth (assuming a resin-to-fiber ratio of 50:50) and apply three rolled epoxy coats to fill the weave of the cloth, i.e. “fill coats.” Continue reading

Plywood selection weighs flexibility vs. stiffness. The wing mast required flexibility. A trimaran interior shows varied uses of plywood selected for their appropriate stiffness and finish.

Marine-Grade Plywood Basics

by Captain James R. Watson

Above: Marine-grade plywood basics include knowing how to select marine-grade plywood for flexibility vs. stiffness. This wing mast required plywood with some flexibility.

Since so many projects in Epoxyworks incorporate plywood, we felt it might be valuable to discuss briefly the types of marine-grade plywood and some construction methods best suited to it. It’s easy to understand why people like plywood and choose it for so many projects: it is readily available, comes in convenient sheets (typically 4’×8′), is pretty light for its stiffness and strength (1/8″ plywood weighs about 11 lb per 32 sq ft panel), and is a bargain when compared to the price of many composite panels. Continue reading

WEST SYSTEM 804 Reusable Mixing Sticks

Product Highlight: 804 Reusable Mixing Sticks

Reusable Mixing Sticks are practical mixing, application, filleting, and cleaning tools that have found many places in our workshop and toolboxes, and we believe they will be in yours, too. The squared, beveled end reaches into the square corners of the 805 and 806 Mixing Pots for thorough mixing of epoxy and blending of fillers. Continue reading