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SAFETY FIRST!
(please read)

OVERVIEW
  terminology

EQUIPMENT
  a. required tools
  b. ski press
      - press frame
      - mold
      - bladder
  c. core profiler
  d. edge bender

SKI
CONSTRUCTION
 
a. materials
  b. graphics
  c. ski design
  d. template
  e. base
     edge bending
  f. wood core
     - lamination
     - sidewalls
     - profiling
     - tipspacers
     - inserts
 g. composites
 h. topsheet

LAYUP
 a. preparation
 b. layup

FINISHING

TESTING

VIDEOS
Free Video: Intro to Ski Building (30MB).  Get an overview of the process.



Wood Core

Overview  The majority of ski and snowboard manufacturers use wood for their cores.   Some of the reasons for doing so is that wood creates a more responsive ski and is also very durable.   We use wood for other reasons too - it's easy to find, simple to work with, and less expensive compared to other core materials.   Typically a wood core is composed of separate strips of wood glued together to form a laminated blank core.   This piece then undergoes a profiling process that tapers the thickness of the core; thickest near the center.   The product, called a profiled core, defines how your ski will ride.  


 



Selection
  The first step in core construction is wood selection.  The most common types of species used within the ski industry include: ash, maple, birch, spruce, aspen, fir, and poplar.    When choosing wood, the major parameters that should influence your decision are:  stiffness (modulus of elasticity), strength (modulus of rupture), and weight (density).  The table below compares these properties for several common wood species.

Common Name

Modulus of Elasticity  (kg/mm2)

Modulus of Rupture (kg/mm2)

Density         (g/cm3)

Ash, black

1126

8.97

0.526

Ash, blue

984

9.82

0.603

Ash, green

1170

10.04

0.610

Ash, white

1249

11.01

0.638

Aspen

838

6.04

0.401

Birch, gray

797

6.88

0.552

Birch, paper

1119

8.79

0.600

Birch, sweet

1520

11.81

0.714

Birch, yellow

 n/a

11.88

0.668

Fir, balsam

879

5.42

0.414

Fir, silver

1076

6.69

0.415

Maple, black

1141

9.37

0.620

Maple, red (soft)

1155

9.35

0.540

Maple, silver

805

6.34

0.506

Maple, sugar (hard)

1290

10.97

0.676

Poplar, balsam

716

4.76

0.331

Poplar, yellow

1058

6.52

0.427

Spruce, black

1069

7.24

0.428

Spruce, red

1071

7.15

0.413

Spruce, white

1001

6.38

0.431

Most if not all of the above woods can be found at a decent lumber supplier.   The cost is pretty moderate depending on the grade averaging $2-$5 per board foot.  

There is really no easy way to figure out which wood will best suit your needs without some experimentation.   One approach is to use a single specie for the first few cores.   This way you can concentrate only on the measurable dimensions (core thickness, wood strip thickness, etc.) to determine their affect on the core’s stiffness, torsional rigidity, etc.  Once you feel comfortable with how these properties correlate to the measured dimensions you may then want to investigate how other woods react.    

After the wood is selected the next step is lamination

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