Overview  Several preparations have to be made before pressing the ski.   These steps are outlined below:

Step 1  Clean the mold.   Try to make the mold as particle and dust free as possible.   Even the smallest wood chip will leave an impression in the base material.   A vacuum, blow dryer, or even a damp cloth can be used to remove most of the particles from the mold. 

Step 2  Prepare the painters plastic bag.   Laying up a ski requires the use of epoxy which can overflow from the mold.   This can ruin your mold and make a mess of your workspace.    You can prevent this from happening by two methods.

The first and probably best method is to use some smooth plastic that does not bond to epoxy.  HDPE and some acrylics work well for this application.   Cover the mold with the plastic (about 1/8" thick) and screw into place.  The epoxy simply peels off the plastic leaving the mold clean for the next pressing.   Using this method, however, requires that your mold be relatively large so that the epoxy does not run off the mold and into your press.

The second method is to use painters plastic to create a bag, or envelope, that holds the excess epoxy.    First cut a rectangular piece of painters plastic that is longer than the ski by approximately 5 inches on both sides and that is wider than your mold by 12 inches on both sides.   Center the plastic with the mold and secure in place using some double-side tape as shown below.

Use the thinnest tape as possible and only tape near the edges of the mold where it won't interfere with the base material.    After all the ski materials have been placed on the mold, the sides of the excess plastic are folded over the top to form a bag. 

Step 3  Bend the tips and tails of the base material to fit into the mold.

If the edges pop off of the base while bending simply tack them back into place with some more super glue.   By pre-bending the edges to fit into the mold it lessens the chance of the edges popping off while being pressed upon by the bladder.   They don't have to be bent to perfectly match the mold.   The bladder will take care of the rest.       

Step 4  Clean the base of any particles or dust.   Place the base with attached edges on top of the mold that is covered with painters plastic.  Try to center the base as accurately as possible.   Secure the middle, tip, and tail with some of the same double-sided tape as before.   Don't use too much, just enough for the ski to hold its place.  This will prevent the base from shifting around while being pressed.  You'll want to tape the base through the plastic and directly upon the mold itself.  The reason why is that the painters plastic can shift due to its elasticity which would allow the base to move.  To tape the base to the mold first cut some small holes in the plastic with a razor to reveal the mold as shown.

Now just apply the tape over the hole and the base will have a secure foundation to tape to.

Step 5  The core can also shift while being pressed.  To prevent this we nail the core to the mold during layup.   Pre-drill several small holes (1/32" inch diameter) in the sidewall material where they will clear the edges.  

Depending on the core and sidewall design, you should have several centimeters to work with.   Make sure your nails fit snugly into the holes and they clear the base.

This is a crude method to prevent core shift but it works.   There are better methods, but this is the simplest.

Step 6  Pre-drill the top sheet material for the insert pattern.   This step is optional but it ensures that the inserts will be visible afterwards.   This eliminates the guess work from drilling out the insert plugs. 

Another option is to simply use inserts with magnetized caps.  These allow the hidden inserts to be found using some iron fillings and makes the drilling process foolproof.

Step 7  Double check to make sure all the materials are cut to proper width and length.   There's nothing worse than to realize that your fiberglass is too short while trying to lay up the ski. 

Step 8  Clean all materials from particles, oils, etc.   Clean materials bond better to each other.   Particles can also leave indentions in your ski if they are not removed beforehand.  

Step 9  Inspect the press.    Make sure your press frame is operating safely.   Also check if your bladder has developed any leaks.      

Once all the above have been completed you can begin the actual layup.