So you are seeing most of the first 3 pairs that I have built. There is a 4th yet to press.
The two skis in the middle (rounded rectangles) are the first pair that I made. They are mid fat (125/90/115) and relatively soft (10mm at center, 200mm foot platform, 2mmtip and tail). They are a simple 22 oz fabric construction with a rubber /ABS tipspacer, and VDS rubber running the full length of the edges. GFX are simple cut paper.
Construction was easy enough, but on flexing the ski the tail delaminated very clean at the interface with the ABS so I have decided to make future tipspacers short of the end of the ski to allow the glassfiber to come together to get a better bond of the structural layers.
The skis on the right (sawtooth design) are / were my fat (135/100/120) skis. A soft construction - again 22oz fabric over a core that is 10mm at center, but with no foot platform, so the tips are very soft. I reinforced the underfoot section by use of an extra layer of glassfiber for about 1.5'. This underfoot section ends with a 45 degree V so that there is no sudden discontinuity in longditudinal stiffness, but the 45 degree fibers reach even further down the length of the ski which was hoped to give better torsional stiffness when things get a bit icy. Tips have used rubber damping under a thin wood extension to the core, but they stop about 10mm short of the edge to allow the two layers of fibreglass to bond together which I hope will reduce the chance of delam (no plastic bond at the critical high stress point).
All in all these skis look and flex great, unfortunately with both skis the alignment pins snapped during pressing and the cores are misaligned from the bases. No idea why this happened at all and we didn't change anything in our setup. :-(
The lone ski on the left is mid fat (125/90/115). The second is in the press. This ski has been made very stiff with multiple areas of damping rubber - similar to BK's Kewah (sp?). The ski is built with the typical 22oz 3 axis fiberglass, and the same underfoot reinforcement used in the sawtooths. The core is about 11 mm thick with a 600mm platform and the tips tapering sharply to 2.5mm. I think they will be like planks!
The GFX were printed on a large inkjet plotter - the white areas have gone slightly translucent. I'll let you know how the ink holds up with UV bleaching, but I hope that the topsheet will filter enough to minimize this.
So a few problems with alignment (shame it was on my favorite cores!). But generally going OK.
The Press:
Photos to come but the press deviates from the skibuilders format a little - I have used an MDF mold, which has a 1.4KW silicone heater mat on top (easily gets up to 221F). I then use 2 sheets of spring stainless steel, one below and one above the skis to form a sandwich. These sheets are sprayed with mold release to prevent them getting covered with epoxy.
I use no plastic, but epoxy that squeezes out of the skis onto the steel cracks off easily., there are a few dribbles down the sides of the mold but this doesn't bother me.
The skis are not finished because I am having a shocker trying to cut these things out - I cannot find blades or a jigsaw man enough for the job - they overheat within 5cm and bend over which is dangerous as it can cut at an angle into the ski. No one else on here seems to have any problems with this process so I am not sure if it is my ABS sidewalls that are the cause of the problem, but I think I am going to have to buy a bandsaw to cut them out. Any suggestions welcome.
B.
P.S. If anyone is upset by the slightly risque GFX let me know and I will censor the image, but I figure is is sufficiently obscured not to cause offense. This is my fight against New England puritanical attitudes!
