Category Archives: Materials Testing

Shelf Life in Real Life

While WEST SYSTEM® epoxy has a long shelf life, age will eventually affect its handling characteristics and cured strength. When stored for very long periods, hardeners may turn darker (reddish to purple), become thicker and give off more odor. 105 Resin may lose some clarity and also become slightly thicker. Use extra care when mixing age-thickened products (stir extra thoroughly), and don’t use old epoxy if color or clarity is crucial to your project. Continue reading

Epoxy Compression Test in Progress

Determining Epoxy’s Physical Properties

BY MIKE BARNARD

In this article I’ll describe our standards for testing epoxy and how we test epoxy to determine its handling characteristics and cured physical properties.

Testing Standards
These are the standards we follow no matter which epoxy we are characterizing.

Two-week room temperature cure
After proper metering and thorough mixing epoxy will continue to cure after it has solidified, until all amines have paired up. Over years of testing we have found that two weeks of curing at room temperature, which we define as 72°F (22°C), is a good indication of its full strength. Continue reading

Letters to the Editor – White Oak

By Bruce Niederer

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.

My article, White Oak Redux (Epoxyworks 34) generated two responses we wanted to share. The letters, along with my replies, follow. Continue reading

Adhesive Bonded Structures

By Jeff Wright

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

White Oak Redux

White Oak Redux

By Bruce Niederer and Bill Bertelsen

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

Sanding

Sanding Tricks of the Trade

BY DAMIAN MCLAUGHLIN

All of the boat builders that I know have little tricks that make a job go faster or do it better. Fairing a 40′ custom-built hull is an arduous task which is often accomplished with two-man teams and fairing boards. We do 90% of the work with a grinding device. Almost everyone in the business will agree that a grinder will remove a substantial amount of material quickly. The trick is controlling that removal. Continue reading

Shop Floor Testing Methods

Shop Floor Testing

By Jeff Wright

Boat builders or advanced hobbyists often want to learn more about the characteristics of the fiberglass laminate they’ve just created. But sending samples to a professional testing laboratory can be expensive and impractical. Fortunately, there are some tests you can do in the shop that yield reasonably accurate results.

Before you begin to test laminates in your own shop, it’s important to understand the difference between shop tests and standardized tests. Many organizations such ASTM, ISO, or UL provide established test procedures defining a specific test method. These may specify things like sample preparation methods, equipment and acceptable environmental conditions. These standards allow the test to be repeated by different people at different locations all over the world.
Continue reading

So Stands the Mighty Oak

By Bruce Niederer

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.

We’ve been debating the issue of gluing oak ever since. Continue reading

Testing for Damage Tolerance

By Jeff Wright

Ted Moores and his company, Bear Mountain Boats, build wood epoxy strip plank canoes, manufacture kits and publish books on building strip plank canoes and kayaks. This method of construction provides a very light yet stiff structure and also enables the hull shape to have compound curves. Moores has 30 years of experience and his designs have logged many safe miles. He understands the forces boats are subjected to when paddled on the water and during transportation. Continue reading

Saving foam roller covers

Saving Your 801 Roller Frame

By J.R. Watson

When you’ve completed a coating task using a 801 Roller Frame and 800 Roller Cover, what next? The roller frame is reusable. But if you leave it resting in the pan while the residual epoxy cures, you‘ll probably ruin both the reusable pan and the roller frame. If you lay the roller and frame on a work bench, it will be stuck there the next day.

Setting the roller on a piece of plastic will bring you closer to success but in any instance where the roller frame rests on a surface while the epoxy cures, the cover will accumulate Continue reading