Overview  A core is profiled to give its unique flex pattern.

Linear Tapered Profile The linear tapered profile is the easiest to make and a side view is shown below.

The tip and tail portions (highlighted in blue) are typically 2-3mm thick.   If they were any thicker, the wood in these areas would have to be steam or heat treated so that they could be bent properly.  At 2-3mm the wood can be easily bent by the forces of the press alone without any treatment.  

The binding area (highlighted in red) is the thickest part of the core, ranging 9-15mm in thickness.   The length of this area can be of any size.   But keep in mind that a longer binding area will reduce the amount of flex in the ski.   For example, if the binding area in the above illustration were lengthened towards the tail of the ski, the tail portion would not flex as much as it originally did.   This is a simple method in which you can stiffen up certain portions of the ski.   For our first few skis the binding area was only as long as our binding mounting surface (about 30cm).  This makes for a smooth flexing core that feels similar to our skis purchased from the industry.  

Also, stiffness not only depends on the thickness of core but also on it's width.  A ski with a 110mm waist will be much stiffer than a 90mm waist ski even if they have the exact same core thickness.   

Other Profiles  Although the linear tapered profile is the most common, other profiles exist.  An example of a parabolic profile is shown in the following illustration.  

It is also possible to make a hybrid profile combining properties of a parabolic with a linear tapered.  Below is a profile with a parabolic taper towards the tip and a linear taper extending towards the tail.

These are just a few examples of how a wood core can be profiled.

Step 1:  Plane Base-Side:  First start off by planing one side of the blank core with attached sidewalls.   This will serve as the bottom, or base-side, of the core.   Note that if you used the "moat method" in attaching your sidewalls you will have to plane the core enough until the sidewalls are exposed through the bottom.  If you don't have a planer you can set up your core profiling jig with some straight rails.   By passing your router over the core with this setup you will have essentially planed one side flat. 

Step 2:  Create Template The next step is to create a full scale template of your profile.   This can be done by either using your CAD software or by hand.   Cut out the template and attach to the side of the core with some adhesive.  If you don't want to make a template another option is to use a ruler and marker to draw the profile on the side of the blank core itself.    Either way, the template or drawing will allow you accurately set the depth of the cutter while profiling.

Step 3:  Profile  Set up the profiling jig of your choice and profile the core.   It's best to profile the core in several passes.   If you try to cut too deep at once, you may possibly ruin the cutter or most likely the core.   It's important that you take your time and profile the core as accurately as possible.   Also, be careful of the dust and flying debris while profiling and protect yourself with mask and eyewear.    

Step 4:  Finishing  Afterwards, check to make sure your core has been accurately profiled.   Smooth out the core with a belt sander using some coarse grit paper.   Beware that a belt sander can remove a lot of material so only apply a small amount of pressure.   Leave the core sanded with the rough sand paper.   Don't try to achieve a shiny smooth finish because epoxy won't bond as well to a smooth surface.