Mold

The ski mold is one of the most critical tools of ski building. The tip, tail, camber, and rocker of the ski is created by the mold. The mold must be precisely shaped and must be able to handle pressure up to 30 psi (9' x 12' mold @ 30 psi = 19,440 lb). I have always built my molds out of wood because it is cheap and has adequate compressive strength.

To start the mold building process, I purchased two 4' x 8' x 1/2"sheets of MDF (http://en.wikipedia.org/wiki/Medium-density_fiberboard) and a sheet of 4' x 8' x 1/8" tempered hardboard (http://en.wikipedia.org/wiki/Hardboard). The molds have three separate features, the tip, tail and camber sections. These sections are individually cut out, then "woven" together to create the final mold.

The first step is to rough cut the MDF with a table saw.

Next the paper templates are glued to the sections they represent; spray glue works best.

The three MDF sections are then cut with a jigsaw using the templates. These cut sections are then used to trace the shape onto every piece that makes up the mold.

The individual pieces are then clamped together so that they can be sanded to the same shape; a belt sander works best.

Once this is complete, the sections are glued together and once dry, sanded on both sides to create a smooth contour.

In parallel the hardboard is cut so that it can be laid on top of the MDF frame work. Two 1/8" layers are used to increase the resistance of the hardboard to flex into under load. In the past I used a single layer of 3/16" hardboard; this is more challenging because the hardboard is relatively stiff and must be bent to the shape of the mold.

The hardboard is then clamped to the frame work. To get the hardboard to the proper contour, the remnants were saved from the tip and tail sections and were screwed together to press the hardboard into place.

Finally end-caps are cut out and placed on the ends of the molds to reinforce them. These ends are then rounded off with a sander to prevent damage to the air bladder which will be used to press the skis.

Finished Molds: