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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.



Building a Pneumatic Press Frame

Warning  Building and operating a ski press can be extremely dangerous.  You can injure yourself and others and in some cases you can even die.  We recommend that you wear protective eye wear at all times.  If possible we also suggest building a structure (e.g. an enclosure for the press) to protect yourself if the press malfunctions or self-destructs.  Exercise caution at all times.

Overview  A ski press is one of the most important pieces of equipment for ski building. The main function of a press is to simply provide high, uniform pressure to squeeze ski materials together to form a ski.  In the case of pneumatic press, all of the ski materials, molds, and bladder are placed inside a strong and rigid structure, or frame.  An example of one our frames is shown below.  (Note the reinforced design.)


 



10 Easy Steps to Build a Pneumatic Press Frame  The following steps outline how to build a relatively simple pneumatic press frame with items that are readily available at your local DIY store such as Home Depot.  A diagram of the frame is shown below.

Note that this frame design is only meant to withstand operating pressures of 40-50psi.  If higher pressures are desired you can easily substitute with stronger materials such as thicker tubing or even I-beams.  Also the dimensions provided in this howto are guidelines.  Your press frame should be designed specifically for the bladder you choose, the mold dimensions, the desired operating pressures, etc.  It is recommended that you consult a certified engineer when designing and building ANY ski press or ski building equipment.

Step 1:  Gather the Following Materials

  • 2" x 2" x 78" - 0.075" thick square steel tubing (8 pieces)

  • 2" x 2" x 12.5" - 0.075" thick square steel tubing (14 pieces)

  • 2" x 2" x 10.5" - 0.075" thick square steel tubing (14 pieces)

  • 1.5" x 1.5" x 12.5" angle iron (14 pieces)

  • 5/16" diameter x 12.5" threaded rod (14 pieces)

  • 5/16" diameter x 9" threaded rod (14 pieces)

  • 5/16" nuts and washers

Step 2:  Prepare the Beam Tubes (BT)  The eight beam tubes are constructed using the 78" long square steel tubing.  Prepare the tubes by drilling seven equally spaced 5/16" diameter holes as shown.  Make sure to drill completely through both walls of the square tubing so that a threaded rod (5/16" diameter) can fit smoothly. 

Afterwards, arrange the tubes side by side and check the alignment of the drilled holes by using the threaded rods (5/16" diameter).  Correct any misalignment of holes before continuing.  Please remember that drilling through steel can be a very dangerous operation, so seek expert advice/training and wear safety goggles at all times.  It is recommended that a drill press be used to drill the holes.

Step 3:  Prepare the Support Legs (SL)  The support legs provide the vertical structure for the frame, separating the bottom and top beam tubes.  The support legs are constructed out of 10.5" long square tubing.  Prepare the legs by drilling 5/16" diameter holes 1" away from the ends as shown. 

Note that holes need only to be drilled through one wall of the square tubing.  Make 14 identical pieces of support legs.

Step 4:  Prepare the Cross Members (CM)  The cross members provide additional reinforcement for the top and bottom beams.  Without them the beams could bend significantly while the bladder is inflated which could possibly lead to failure of the press.  The more cross members you have the better, but a minimum of five should be used.  In our design, we use seven.  The cross members are prepared in the same manner as the support legs described above, with the exception of length: the cross members should be 12.25" long. Again, 5/16" diameter holes are drilled 1" away from the tube's ends.  Make 14 identical pieces.

Step 5:  Prepare the Angle Iron  Angle iron is used to provide extra reinforcement for the cross members.  They simply slide into each cross member tube and then bolted inside.   Prepare the 12.25" long angle iron by drilling 5/16" diameter holes 1" away from the ends as shown below.

Note that some of the angle iron pieces in the above picture have holes drilled through both walls.  Please ignore this and drill holes only through one side of the angle iron.

Step 6:  Castors  If you would like a mobile press then castors are needed.  Attach the castors to cross members. Depending on the castors you select you may need to modify your cross members appropriately.  In our case, the castors have a larger base (3"x3") than the square tubing and we had to double up on our cross members to provide sufficient mounting surface.  We simply made 2 more cross members and bolted them side-by-side as shown.

Step 7:  Attach the End Support Legs   With your top and bottom beam tubes (BT) aligned, elevate them (using wood, milk crates, etc.) and secure four support legs to the two ends of the beams using the 12.5" long threaded rod and bolts as shown.

It helps to have the beam tubes (BT) flipped on their side for this step as depicted above.  Use a T-square to make sure that the support legs and beam tubes are perpendicular to each other before tightening the bolts.  

Step 8:  Attach Remaining Support Legs  After the end support legs are securely bolted, rotate the assembly 90 degrees and attach the remaining 10 support legs.  Check to make sure the frame is square.  Tighten all bolts when the frame is square.  The frame should look like the following:

Step 9:  Attach Cross Members  The final step involves attaching the cross members and angle iron.  With the frame elevated, assemble the cross members and angle iron to the frame using the 9.5" long  threaded rod, washers,  and bolts as shown below.  Note that each threaded rods is concealed within a support leg tube, and the angle iron is inside of the cross member.

Here's what the frame should look like when the cross members are secured:

Step 10:  Testing  Take time to admire your work.  Now it's time to test the frame -- this is a most dangerous part, so please exercise caution.  The test requires a bladder and molds, so build them before testing.

Begin the testing by inserting your bladder and molds into the press.  With your safety glasses on, slowly inflate the bladder to 5 psi and observe the press for any noticeable signs of significant beam deflection (0.25"+), cracks, loose bolts and nuts, etc.   If everything looks okay then slowly increase the bladder pressure by 10 psi and observe again.  Continue this process until you have reached the maximum operating pressure of 50 psi.  Once you've successfully reached 50 psi with no obvious issues, leave the system inflated for at least 12 hours to further test it for potential time-dependent failures.  During operation, periodically inspect the press for potential damages, signs of fatigue, or other safety issues.

Finally, we recommend that some sort of strong enclosure be made to house the press during operation in the event of a failure.  Remember that the force exerted by an inflated bladder can be extremely large and can potentially hurt you and others around.  Exercise caution at all times by wearing protective eye wearing, a mask, and even a helmet.

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