Category Archives: Bonding

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

Testing Bolts Bonded into Concrete

By Brian Knight

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

G/5 Adhesive Tips

By Tom Pawlak — GBI Technical Advisor

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

Testing large fasteners

Testing Large Bonded-In Fasteners

by Brian Knight

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. We first looked at Scheherazade in EPOXYWORKS 17, Spring 2001, before she was rolled and set on her 153,000 lb ballast keel. On a March, 2002 visit, Scheherazade was resting on her massive keel (cover), while far above, surrounded by multiple levels of staging, work continued on her interior and deck (below). Continue reading

Bonding to Corian™ and Wilsonart™ Laminates

By Tom Pawlak — GBI Technical Advisor

We recently did adhesion testing to Corian and Wilsonart surfaces with WEST SYSTEM 105 Resin and 206 Hardener at the request of a composite panel manufacturer. Corian and Wilsonart are mineral filled acrylic panels that look like granite and are often used as countertop material in kitchens and offices. Cabinetmakers and contractors typically use the panels in ½” thickness for residential applications. They are quite heavy, though not nearly as heavy as actual granite. Continue reading

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

Hardware Bonding

By Tom Pawlak — GBI Technical Advisor

My first experience with hardware bonding occurred shortly after starting work at Gougeon Brothers in 1980. Having just been hired into the wind turbine blade plant, I was excited to be part of this interesting company. Continue reading

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

Joining Plywood

Joining Plywood

Choosing the Best Method for the Task

By Captain James R. Watson

A long time ago, I was building a 16 foot William F. Crosby design—a plywood, skiff-like sailboat. I was having trouble figuring out what to do because the plywood was only half as long as my boat was going to be. (Up to that point, all the boats I’d built were 8 footers.) I thought my prayers were answered when I heard that a distant lumber yard had some “special stuff” 16 feet long. But when I arrived at the yard, I thought I had been deceived. The “special” 16 foot plywood had been made that long by joining two standard 8 foot sheets, with a joint that looked pretty vulnerable and weak. I reluctantly bought the material on the assurance that it was plenty strong and I was not being deceived. Continue reading