Category Archives: Techniques & Tips

Chopped Strand Mat

Chopped Strand Mat and Epoxy

by Tom Pawlak — GBI Technical Advisor

Above: Wet-out chopped strand mat and woven fabric test samples are prepared for moisture uptake testing.

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 of weights between .75 oz to 3 oz per square foot. The most popular weights are .75 oz and 1.5 oz. 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 →

Screw strip out of particleboard furniture

Furniture Repair with G/5

A good method for particleboard furniture repair

by Tom Pawlak — GBI Technical Advisor

Above: Particleboard furniture repair can be tricky when screws strip out. G/5 Five Minute Epoxy Adhesive offers an easy solution to fixing inexpensive furniture when this happens.

I recently broke the leg off an old workshop table. The tabletop was made of particleboard covered with Formica®. The screws holding the leg in place had pulled out and taken chunks of particleboard with them. Continue reading →

Testing Bolts Epoxy Bonded into Concrete

by Brian Knight—GBI Technical Advisor

Above: The final version of the test Brian devised to determine the holding power of bolts epoxy bonded into concrete. When the load cell registered 4000 lbs, he stopped the experiment.

The email exchange with Bob Warters in the article Installing a basketball goal is typical of the process we sometimes go through to answer a technical question. Most questions do not generate laboratory testing, but, in this case, the data we had available was limited. I was able to give Bob some shear strength data on concrete block from previous tests but was unable to find specific data on fasteners bonded with epoxy into poured concrete. I suspected poured concrete would hold a bolt better, but another data point would be reassuring. 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 →

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 →