Tag Archives: Spring 2006

Fabricating an Air Scoop

Using the Lost Foam Method

By Brian Knight

I used lost foam construction to fabricate a fiberglass air scoop for my son’s Formula Continental C race car. Our project started because a modification to the shape of the race car body necessitated the construction of a new air scoop. The air scoop is bolted to the car body so if either the air scoop or the body is damaged (a very likely scenario), the repair will be simpler. To fabricate the scoop, I made a Styrofoam male mold, surrounded the mold with fiberglass, and then dissolved the Styrofoam to leave a hollow part. I used Styrofoam to build the male mold for several reasons. It is readily available at most lumberyards, it is easy to shape with files and sandpaper, and it is easy to dissolve with lacquer thinner.

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Scheherazade Update

Courtesy of Hodgdon Yachts

Above: Scheherazade is a 155′ Bruce King-designed ketch built by Hodgdon Yachts in Boothbay, Maine and launched September 27, 2003. Photo by Onne van der Wal.

Cover Photo: Scheherazade, a 155′ Bruce King-designed ketch. Image by Onne van der Wal.

Hodgdon Yachts of East Boothbay, Maine launched the 155′ ketch, Scheherazade. She is a beautiful union of wood/epoxy technology, elegant design, and superior craftsmanship. Continue reading →

The Limitations of Statues

Statue Repairs with Epoxy

by Bill Bertelsen, GBI Test Engineer

Above: Statue repairs are underway on “Shep,” a molded fiberglass figure that was knocked off its base and belongs in the outdoor nativity set of St. Luke’s United Methodist Church in Essexville, Michigan.

Creating lasting outdoor art has challenged humans since the dawn of time. One has only to think of the pyramids (still there), Stonehenge (mostly there), the Colossus of Rhodes (long gone), or the Easter Island monoliths (surviving, but then two heads are better than one). In more recent times, there’s Mt. Rushmore, Stone Mountain Georgia, and the Statue of Liberty. The goal is nothing less than perpetuity. But of course, outdoor sculpture needs to be done right or it won’t last. Making statues, e.g., permanent structures that look like people, is particularly difficult. Continue reading →

Building a Masthead Fitting

by Captain James R. Watson

Above: The nearly finished masthead fitting Captain Watson fabricated using the lost foam method of creating custom parts.

Here’s another use of the lost foam method to produce a custom part with a molded interior cavity. In this case, the part was a masthead fitting to hold an internal sheave and provide a route for the halyard to pass. This method can be adapted to a variety of other applications, as demonstrated in Fabricating an Airscoop. Continue reading →

If You Can’t Take the Heat…

Understanding Epoxy and Heat Deflection Temperature

By Bruce Niederer — GBI Technical Advisor

Above: The test apparatus holds five of the test samples shown below in a bath of heated oil while a three-point load is applied to the sample. It is used to determine heat deflection under load (HDUL) temperature and the effects of high temperatures on cured epoxy.

Among both professionals and amateurs in the world of composites, there are certain enduring misconceptions and rumors regarding the effects of elevated temperature on an epoxy bond. Armed with just enough misinformation to be dangerous, folks will make important decisions that can lead to costly or time-consuming mistakes that might have been avoided—if they had an adequate understanding of the principles that encompass epoxy structures and temperature. By defining some commonly used terms and briefly discussing issues surrounding epoxy application, we hope to dispel some of these misconceptions about epoxy and heat.

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Rebuilding an International 110

By Tim Botimer

Above: Tim’s International 110 sailboat. After winning the National championships, he gave her a new coat of paint.

I first got into International 110 sailing 15 years ago and soon bought an old fixer-upper boat. After sailing it for a couple of years in a decrepit state, I made the decision to fix it right. I had worked with WEST SYSTEM® products before, and I was pretty familiar with the product line. I had done significant repairs on a 1965 plywood Thunderbird and a 1950s vintage Flying Dutchman, which incidentally was one of the original test boats when Jan and Meade Gougeon first came out with the product. I had never tackled anything on the scale of the 110 project, and at the time it was the only boat I had. Continue reading →

Comparing Cost and Weight of Flat Panels

How to choose the best materials when building flat panels

by Jeff Wright — Vice President of Technical Services

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 →

Practical Uses for Razor Blades

by Tom Pawlak — GBI Technical Advisor

Necessity is the mother of invention, and razor blades are often called into service for a variety of tasks around the shop other than shaving. Here are a few.

Mini-Spreader

Razor blades can be used in a pinch to apply caulks and thickened epoxies with great precision. They do a great job filling isolated pinholes and scratches, especially when the blade is laid at a low angle (nearly flat) when spreading the putty. Continue reading →

Building a Guillemot Kayak

By Jason Havel

I am a Captain in the Air Force and was stationed in Wichita, Kansas, in October 2002 when I purchased a book about building a strip kayak. After the first chapter, I was sold. I ordered the full-size plans for the Guillemot kayak. While on vacation in Texas, I spent about $300 on the western red cedar, purpleheart, and yellow heart, then discovered I was to deploy to Saudi Arabia. In the evenings prior to the deployment, I machined the cedar into ¼” strips and put the bead and cove on them using a router table. It was during the process of setting up my table saw that I realized how clear D-grade pine can be. I accidentally bought a few long boards of it to build an extra-long table saw fence for ripping the cedar.

The stripping of the Guillemot kayak’s hull with Western red cedar is completed.

I was amazed at how little grain was visible. That’s where the idea of the lighter-colored deck came from. I got 6 or 8 strips on the mold before I left for my deployment. While I was gone, the confrontation with Iraq began. What was supposed to be 3 months turned into 5 months. The air war ended and I came home and was informed I would be moving from Wichita, Kansas, to Altus AFB, Oklahoma. I knew it was only 300 miles, but I wasn’t about to bring a couple of hundred strips of cedar and an unfinished boat along for the trip. I spent every spare moment finishing the boat. I finished stripping in June, laid the fiberglass in July, and moved in August.

The inside of the Guillemot Kayak’s hull is glassed with 6 oz fiberglass cloth. Havel used 105/207 to wet out the cloth in temperatures over 100 degrees F.

I used 6 oz cloth with 105 Resin/207 Special Clear Hardener and was very impressed. Since July in Kansas is typically over 100°F, I was a little hesitant pouring epoxy. When I did all the epoxy work, it was 108° to 112°F. I could thoroughly mix the epoxy, lay it down, brush or squeegee it out, and make it look perfect. Ten minutes later, it started to harden. There were no issues with sheeting or running. In fact, I never saw any anime blush and had zero bubbles. Believe me, I looked for amine blush since every piece of the literature mentions it. After an hour or two, I brushed on the next coat to fill the weave and add a nice smooth surface for the varnish. Since the epoxy wasn’t fully cured, I got an excellent chemical bond. I can’t say enough about how great the 207 Hardener worked at over 100°F. I coated everything with epoxy, including the deck fittings, before I fastened them to the deck. I sanded the hull with 150-grit sandpaper on a random orbital sander and finished it off with five coats of Z-Spar™ Captains Varnish. Z-Spar also works great at 100+ degrees.

Guillemot Kayak detail: Everything is coated with 105/207 and finished with 5 coats of Z-Spar Captain’s Varnish.

Purpleheart provides a nice contrast for the outline of the deck design and deck hardware on the Guillemot Kayak.

I’d do it again in an instant but next time it will be a canoe since my family will soon be a total of four plus our dog. Even though the kids will be small, it’s tough to stuff them and my wife in a single place kayak and expect to get anywhere.

Giving BOUNTY HUNTER New Skin

by Patrick Ropp—GBI Technical Advisor

Above: The 65′ strip-planked Bounty Hunter after sheathing with fiberglass and WEST SYSTEM Epoxy. After 5 years, she still looks as good as she did then. In addition, her new fiberglass skin quickly paid for itself through increased performance.

Five years ago, Captain Glenn James decided it was time to make improvements to his Coast Guard-inspected charter fishing boat operating out of Edgewater and Solomon’s Island on the Chesapeake Bay. Bounty Hunter is a 65′ cedar-strip planked hull, a one-off Davis™ hull that was built in 1967 at Harkers Island, North Carolina. The planks are fastened to frames on 16″ centers with monel fasteners. The cedar strips are narrow, less than 2″ wide, and are edge nailed with monel nails and edge-glued. Continue reading →

Epoxyworks

Building, restoration, and repair with epoxy