Handmade titanium bicycle company perfects its craft with U.S.-sourced tubing
November 2011 - In 1991, after fabricating steel-frame bicycles out of the back of a bike shop for 10 years, Steamboat Springs, Colo.-based Moots Cycles made the switch to titanium almost overnight. One of Moots’ welders prompted the change after investigating the availability of titanium tubing in a bicycle-applicable format, recalls Jon Cariveau, head of marketing at Moots.
“There was that kind of a-ha moment of wow: the fatigue, life of titanium is extremely high. You don’t have to paint it, there are some other special processes to use to get it into bike form, but it really went along with our philosophy of building products that really last,” he says.
A full-time production staff of 15 makes Moots’ frames by hand, about 1,500 annually, through a precision process that entails designing, mitering, machining, welding and finishing. Tube diameters and thicknesses vary with each bike’s size to maintain ride characteristics for the smallest through largest size. For example, a 56 cm Vamoots, a mid-size classic road frame, would use 1 1/2 in. OD top tube (from the seat to handlebars) and down tube (seat to pedals), with a 0.032 in. or 0.035 in. wall thickness, Cariveau says.
In its 15,000-sq.-ft. shop, Moots uses a half-dozen Bridgeport mills that are set up for different tooling, depending on the cut, cope or slot desired, according to Butch Boucher, quality control manager. “We’ve made a lot of our own mitering fixtures for specific tasks, that’s why we have so many mills,” he says. Additionally, Moots relies on Haas Automation and SuperMax Tools machining centers. “We try to set up as many dedicated tools as we can to do our jobs.”
Before welding, workers buff the tubes with an abrasive flap wheel to remove the mill edge from mitering, after which they’re treated in an ultrasonic cleaner.
Employees TIG weld the tubes—the same method used for steel. To prevent oxidation during welding, argon is pumped through the frame to shield the weld joint from oxidation. “The difficult part is with titanium, you have to weld it in an oxygen-free environment,” says Cariveau. “What happens is if you weld it with oxygen present, it basically contaminates the weld. The heat and material interact with oxygen and it takes the weld to a point where it becomes very brittle.”
To guarantee sufficient argon protects the weld on the tube’s exterior, “the torch has a cup on the end of it that produces a flow of argon gas onto the surface of the weld,” Cariveau continues. “So we get this back purge and frontside purge that eliminates any of the oxygen.”
The welding technique is equally crucial not only for aesthetics but alignment. “The welders have to have a deft touch,” Boucher says. Moots uses a two-pass weld technique in which the welder first fuses the parent materials together then TIG welds with filler rod as a second pass. “Through testing, we have found this is the strongest weld we can create.”
That weld sequence keeps frame alignment in check, Cariveau says. “As far as when any metal is heated, there’s a little bit of warpage that goes on. We want to minimize that to keep it very balanced.” Lastly, a glass-bead finish is applied. Imagine a satin-gray baby powder, adds Cariveau.
While Moots’ meticulous manufacturing results in one of the highest-end bicycles available—frame sets start around $3,000—the quality of titanium plays the biggest role. Sandvik Special Metals and Haynes International supply Moots with 3/2.5-grade Pi-Tech titanium tubes. They come as seamless tubes, formed directly from a solid or ingot rather than rolled from sheet and welded, says Cariveau. The lack of a seam provides more roundness.
“By far, what we’ve found is that the U.S. mills produce the most consistent, highest-quality certified tubing you can get. If you start out with junk material, you’re going to end up with a junk product,” Cariveau says. However, having a shop that is designed specifically and equipped to process titanium works in Moots’ favor.
“Just maintaining the quality through a daily, weekly, monthly basis is one of our biggest challenges,” adds Boucher. “We’ve got a good group of people that are really interested in doing that.” FFJ