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 →
Above: Jeff Wright, Vice President of GBI Technical Services, poised to take a deep dive into types, materials, costs, weight, and stiffness of flat panels.
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 →
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 →
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 →
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.
Construction of fiberglass tubs and showers uses methods and materials similar to those for building fiberglass boats. Gelcoat is applied to a mold and allowed to cure. Then chopped fiberglass and polyester resin are applied over the gelcoat and worked into the surface. To create a stiff and strong fiberglass tub or shower enclosure, the laminator uses a grooved roller to compact the fibers against the gelcoat. The quality and strength of the laminate depends on Continue reading →
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 →
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 →
It’s difficult to prevent cloth from lifting when fiberglassing around a sharp wooden corner. Even if you were able to lay glass tightly around a sharp corner, it could easily be dented. The slightest compression of the underlying wood could leave a void, and an invitation for moisture and the problems it creates. To avoid these problems, we always recommend rounding over the corner so the glass will lay flat against the surface. However, there may be times when you need a sharp corner. Here’s a method to make sharp fiberglass corners that are strong enough to prevent dents and protect the underlying wood. Continue reading →