We consider ourselves students as well as tech advisors and so are always open to learning something from others. Our readers are generally pretty savvy people, and when they take the time to write us a thoughtful letter, we feel compelled to share what we learn from them with the rest of our readers.
Fiberglass reinforced plastic and other composites influence the design of many products manufactured today. Boat hulls, sports equipment and airplanes can easily take new, complex shapes when composites are used in place of traditional materials. Reinforcing structures also benefit from the versatility of composite materials when prefabricated components are bonded with a high-strength adhesive. This article will discuss some of the engineering aspects to consider when designing or repairing an adhesively bonded composite structure.Continue reading →
Building stuff, especially boats, with wood is much like a religious calling; once you hear the call, there’s no turning back. Those who’ve heard the call will not suffer fools willingly, so when I decided to conduct some white oak adhesion and shear testing and report the results in Epoxyworks 31, skeptics and believers alike took to the internet wooden boat forums-and had no problem speaking their minds! Having healed from the pummeling I took in some quarters, I’m back again to report the promised follow-up test results. Continue reading →
On July 15th, 2006, a friend and I took my 1958 Flying Dutchman out for a sail in the Saginaw River. This was only the third time the boat had sailed in 30 years and the first hard sailing since my six-year-long restoration. We set both sails and made several runs in front of the Saginaw Bay Yacht Club before we hit something, maybe an old piling or maybe the freighter rudder that went missing the previous fall.
The Damage The centerboard took the first impact, splitting at the pivot bolt hole. Next the rudder hit, forcing it upward, snapping the tiller and tearing off most of the transom. The board jammed against the back of the centerboard trunk and gouged a triangle out of the trailing edge of the centerboard. Continue reading →
People have been building boats using white oak for centuries, sacrificing blood, sweat and tears to engineer wonderful and enduring vessels of all shapes and sizes.
Oak was often used because of its desirable properties and behavior. It is dense, strong, rot resistant, holds fasteners well and can be steam bent. In the days before glues and adhesives, oak planking was used because it would swell considerably which resulted in tight and sound hulls, meaning little leaking and dry interiors. Of course, time marches inexorably forward and eventually builders began using adhesives to augment or, in some cases, replace mechanical fasteners.
WEST SYSTEM® Six10 is a two-part, pre-thickened epoxy adhesive formulated with properties that make it perfect for many adhesive applications. Compared to other ready-to-dispense adhesives, its particular physical properties make it ideal for stitch and glue boat construction, fiberglass laminate repair and general bonding. This new formulation has a good balance between the elongation and toughness of G/flex® and the strength and stiffness of our 105 Resin-based epoxies. You can use it with as many materials as possible including wood, metals and composites. The long working time with fast thru-cure and unique shear thinning are additional characteristics formulated into Six10 that contribute to its ease of use. Continue reading →
D-ring pads are often attached to flexible surfaces with urethane adhesives to gain load carrying capacity where there otherwise wouldn’t be any. They are used on waterproof fabric cargo bags, heavy tarpaulins and inflatable boats. They are also sometimes used on the decks of canoes and kayaks to hold cargo in place on long trips. D-rings are not typically used on polyethylene canoes and kayaks because the urethane glues are not recommended for use on HDPE (high density polyethylene) plastic. We decided to experiment gluing D-ring pads with G/flex 655 to HDPE plastic with that end-use in mind. Continue reading →
WEST SYSTEM 105 Resin-based epoxy is a very versatile system. For years, experienced users have been blending the various products in countless ways. For example, users may blend 205 Fast Hardener and 206 Slow Hardener to make a hardener with a modified cure speed. Different uses of 410 Microlight® Filler provide a further example. Many customers assume that the only use of 410 is to make a fairing compound—it is added to thicken epoxy to a peanut butter consistency to create a light, easily-sanded filler. However, 410 Microlight can be used in other ways. Jon Staudacher in Epoxyworks 22 described how he applied a “runny” mixture of epoxy and 410 to fill the weave on a composite part and reduce the Continue reading →
Many of our readers who are familiar with WEST SYSTEM® Brand epoxy products for building and repair already know the benefits of fastener bonding techniques. WEST SYSTEM® epoxy has been used in other industries for many years as well, and these folks apply knowledge and techniques developed in the marine and aerospace industries in their work. A good example is the sign industry, a huge industry in the U.S. with companies ranging from mom & pop garage operations to multimillion-dollar corporations. Continue reading →
We have performed tens of thousands of adhesion tests over the years and many of these tests were done on metal surfaces. Below is a summary of tests done on a variety of metal surfaces and done with a variety of surface preparations. As you look at the chart, notice the surface preparation that gives the highest number.
All the tests shown below were performed using a PATTI (pneumatic adhesive tensile test instrument) meter. We chose this test method as our default adhesion Continue reading →