Every year, about 200 bikes are conceived, grown, and born in a cluster of small warehouse spaces in Bend, Oregon. The offspring belong to Argonaut Cycles.
For just over a decade, Ben Farver and his team at Argonaut have been producing high-end carbon fiber road bikes in Bend. While most custom frame builders work with steel or titanium, Farver wanted to make a carbon road bike with a vertically integrated process.
VeloNews visited Argonaut’s headquarters for a tour of the brand’s patented process.
Ben Farver began building steel bikes in 2007. Over the years he was drawn to carbon, for its performance and potential for customization. A dozen years of trial and error later, Argonaut settled on a unique process the brand calls High Pressure Silicone Molding (HPSM).
Carbon fiber bikes and parts are made by putting pieces of carbon fiber cloth inside a mold, then putting pressure against that fiber — often with an inflatable bladder — and then curing the material in an oven.
Instead of a bladder, Argonaut uses silicone mandrels to press up against the fiber inside the molds. This process allows for greater consistency than using bladders, Argonaut argues, which can result in wrinkled and creased layers of carbon.
A quiver of stem mandrels, waiting for their carbon wrap.
“You can make a really great quality part in a bunch of different ways, right?” Farver said. “In terms of laying it up in the tool or laying it up on a bag are all different ways. But if you want to actually put some consistency to it and scale it, and have it be repeatable and dependable, then that’s where you have to be more creative and consistent.”
Here, an Arognaut employee applies carbon fiber, layer by layer, to the silicone mandrel for a bottom bracket.
“Everything stays where it is,” Farver said of the Argonaut process. “And because we get such good pressures, we get really good surface finish. And so we can just straight spray clear over a frame. And so you get to see all these cool, really intentional pieces of carbon and how we lay them up there.”
Argonaut’s tooling is made in a CNC machine.
During the cure cycle, the silicone mandrel increases internal pressure inside the mold. The pressure is controlled by the size and amount of silicone. O-rings surround the part being cured and seal the mold, keeping resin trapped into the system and keeping internal pressures high. Once the part is cured, the aluminum skeleton within the mandrel helps to break up the silicone for extraction.
Once all the bits have been made, it’s time to get bonded.
But wait, why so many individual parts?
“In a perfect world, from a layup standpoint, you would have one giant tool to make the whole bike with no junctions, right?” Farver said. “But from a ‘makeability’ standpoint, that’d be a giant pain. Say you have a flaw in the chainstay, the whole thing is scrapped. Some of the first carbon bikes like those GT time trial bikes that were made for the Olympics in the 80s, that’s how they tried to make these big giant tools. And as the industry progressed and we learned more about composites and how they work, the frame got broken up into smaller pieces, mostly to make it easier to make and to cut down on scrap.”
Once the frames are bonded, they begin the paint process. It’s not as straightforward as slapping on a layer of color.
“Paint is its own balancing act between chemistry and physics,” Farver says. “Paint needs to look good and also not add weight. It needs to be durable. To be durable, the paint needs to be thick enough, which weighs something.”
Bringing the paint process in-house was another move toward control and consistency.
An Airtech coating is applied to give the frame an even surface. Then, 150g sandpaper is used to scuff it up to give the surface something for the clear coat to grab onto. That also seals the frame. Raw carbon that’s been sanded is porous and can soak up contaminants from the air that will prevent the paint from sticking.
Clear coat. Primer coat. Then it’s ready for color.
Are you really a custom bike company without a custom Rocket Espresso machine?