Category Archives: Materials Testing

Gluing Plastic Dimensional Lumber

By Patrick Ropp

More people are using recycled plastic/wood composite lumber for decks and other various projects. Although each manufacturer of recycled plastic lumber has his own blend, we found that most are using very similar ingredients: an equal amount of melted recycled plastic mixed with recycled wood chips or sawdust and then extruded in the form of dimensional lumber. Since the wood is encased in plastic, the plastic/wood composite boards are supposed to last longer than traditional decking materials and carry a good warranty. Many of these boards are not intended for use as structural members, but they Continue reading

Varnish over epoxy

Testing House Paint Primers

By Tom Pawlak

Gougeon Brothers, Inc. regularly engages in testing to support those who use our epoxy in architectural applications, both in new construction and repairs. In the past, we have tested the compatibility of house paint primers over WEST SYSTEM® epoxy and found that a variety of primers worked well. Latex primers especially performed well when applied over cured epoxy, even when the epoxy was marginally prepared prior to painting (Epoxyworks 7, Spring 1996).

Our goal in a recent series of tests was to identify primer paints that worked successfully over WEST SYSTEM epoxy with minimal surface preparation. Specifically, Continue reading

Mold Release, PVA and Hairspray

By Tom Pawlak

PVA (polyvinyl alcohol) is a water-based liquid plastic that can be applied to waxed molds to prevent molded parts from sticking. PVA is not always required. Often laminators rely solely on mold release wax to create a surface contaminant on the mold that allows parts to be removed. However, on complicated molds and on new molds, when the risk of sticking a part in a mold is greatest, PVA can be applied over a waxed mold to minimize the chance of sticking a part.

PVA can be applied by brush, paint roller or with spray equipment. PVA often leaves a texture on the surface of the mold after it dries. This texture is duplicated or molded into the Continue reading

Thinning WEST SYSTEM Epoxy

By Brian Knight

A question frequently posed to our technical staff is “can I thin WEST SYSTEM® epoxy so it will flow or penetrate better?” The answer to that question is “yes, but not without consequences.” Many of the advantages of thinning epoxy are offset by disadvantages in other areas of epoxy performance.

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Science Fair Testing Wins Awards

By Bill Bertelsen

We like to think that all our customers are considerably above average, but every once in a while we encounter someone really exceptional. On January 25, 1999, our tech service department took a phone call from Elizabeth Tedford, a 7th-grader from Lansing, North Carolina. She was working on a science fair project that involved testing the adhesive strength of epoxy. Continue reading

Hydromat Panel Test, an ASTM Standard

Previous Epoxyworks have reported test results from the “Hydromat,” a unique structural test developed at Gougeon Brothers, Inc. The American Society for Testing and Materials (ASTM), after a rigorous review by its D30 Committee on Composites, approved the Hydromat test method as an official ASTM standard. Continue reading

Porch Railing Coating Analysis

By Tom Pawlak

My porch railing at home was badly in need of painting even though I had painted it the summer before. After just one Michigan winter, the paint had cracked and lifted. I wondered to myself if coating the top rail with WEST SYSTEM® epoxy would improve this poor situation and decided to turn the top rail into a small R & D project. Continue reading

GBI test lab

The Versatility of Epoxy

By Rob Monroe

From ice boats to racing multihulls, wind turbine blades, and a thousand other projects — ours and customers — working with epoxies and our customers since 1969 has been interesting. The decades of experience in the shops, labs and libraries have given us a pretty good feeling for epoxy technology. We know its strengths and weaknesses, and most importantly we understand and appreciate its versatility.

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fastener load path

More on Hardware Bonding

General considerations for epoxy bonded fasteners in wood

By Robert Monroe

With epoxy bonded fasteners, the idea is to balance the three parts, (fastener, epoxy and wood/hole) to obtain optimum performance. The key information needed is the tensile strength of the fastener, the shear strength of the epoxy and the withdrawal resistance of the wood or backing block. Continue reading