GEAR 101: What Is Flipcore?

How It’s Usually Done:

A ski’s core typically starts out as a flat “blank,” composed of different types of hardwoods that are vertically laminated together. In a vertically laminated core, separate pieces of wood are glued together with and adhesive interface (shown in red below) situated vertically and the wood’s grain running lengthwise through the core. Different types of woods may be used to build the core depending on the desired performance characteristics of the ski.

Vertically laminated core diagram, Flipcore
a vertically laminated core with adhesive (epoxy) represented in red

Once the laminated core blank is constructed, the top surface of the core is tapered, or “profiled,” with a machine. Once profiled, the core is usually thickest at its midpoint and becomes thinner toward the tip and tail. The bottom of the core remains flat, like so:

Outline of a profiled core used in explaining Flipcore
outline of a "profiled" core

A ski’s flex is largely determined by the rate of taper in the core profile + the types of wood used to build the core + the pattern in which the woods are arranged in the laminate.

Ok, So We Have a Profiled Core. What Now?

In a conventional manufacturing process, once the core is profiled, it is placed in the mold with the curved (convex) side facing up. Then the core is pressed together with the ski’s other components: fiberglass weave, carbon stringers, base materials, etc.

The final camber shape of the ski, and that of the core at its center, is determined by the mold in which it is pressed.

diagram of how a cambered ski is traditionally pressed
Pressing a traditionally cambered ski

Conventionally, a reverse cambered ski is pressed in the same manner as a traditionally, positively cambered ski. Both use the same tapered core profile with convex taper on top and flat core surface on the bottom (as shown above). Again, the profiled core, with convex side facing up, is bent against a mold using heat and pressure. In order to create a ski with reverse camber, only the press’ mold is shaped differently.

ON3P ski press
One of ON3P's ski presses. Notice the mold with metal topsheet

So…What Makes Flipcore Different?

7 comments on “GEAR 101: What Is Flipcore?”

  1. Interesting article. Makes some sense. I have been under the impression (actually, I was told) that in many ski companies, the camber is actually milled into the core, not just pressed in. While I understand that forcing it to rocker may break these fibers, if I’m not mistaken, then traditionally cambered skis are not being broken. This wastes wood, but helps prevent them from losing camber right away.
    Can anyone comment on this? Is it wrong?

  2. Any chance the introduction of the bamboo core has impact on the properties of the ski than the flipcore construction? After all, ON3P uses bamboo exclusively and you pointed out the stability of skis from that manufacturer in your article. Liberty skis (amongst others) also use bamboo and have been picking up a host of industry awards lately.

  3. I’d be interested in doing a test if Blister wants to help answer some questions. It would be fairly easy for us to lay up an stock Caylor, a ski that Blister has had some experience on, and just flip the cores. It wouldn’t be an absolute true test since the stock and new flipcore skis would have seen different riding conditions and use, but after a two or three day break in period, you could ski em back to back for comparison.

  4. Thanks for explaining this technology. I’m not sure if I understand though…If a core is turned upside down in the press, the press still forces the core to bend from a negative camber shape to a positive camber shape in the waist (since all flip core models seem to have positive camber). Here, the stress on the wood fibers should be increased, or not?

  5. You know what, those guys over at Blizzard are just lazy. One afternoon, after a long day of inhaling wood dust and fiberglass particles, the guy operating the ski press gave the dude passing him the profiled wood cores a look and said, “seriously? you really want me to push the wood against the direction it wants to go? do you know how much energy thats going to take?” Minutes later, Flipcore was born.

    As an aside, the Cochise looks like a great ski.

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