Core

For discussions related to ski/snowboard construction/design methods and techniques.

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kirol
Posts: 34
Joined: Tue May 15, 2007 7:55 pm

Core

Post by kirol »

I plan on making my cores by laminating 1"x4" hardwood planks into a beam like structure then ripping my blanks off of the solid plank. Is this a good method ? and what could I use to rip my core blanks?

Also, do you guys profile your cores before or after cutting the side cut (basic shape) out of them?
Thanks
hafte
Posts: 204
Joined: Wed Jan 11, 2006 11:40 am

Post by hafte »

Hey Kipkirol, I used that method for my cores. My problem is that I don't have a band saw to cut the full width of the ski. I use a table saw to cut the cores. I am limited to a 3” depth of cut and stack no more than 3” deep. I have to cut two parts for each ski and glue them together to make the full width. Then clean them up with the planner a bit after.

I have been cutting a rough plan shape before I run the profile. I found out the hard way that routing the profile shape when the parts are profiled led to the vertically laminated wood coming apart at the tips. I only ran the router along the edges and left the tips for later. If you hit the end grain of the wood with a straight fluted router bit the tip will literally explode. To avoid that problem use a four flute spiral end mill. The end mill will cut the end grain much better, but can still lead to issues.

Hafte
powdercow
Posts: 76
Joined: Mon Jul 31, 2006 1:35 pm
Location: Orem, Utah

Post by powdercow »

I do it exactly like hafte. One nice thing about this method is that you can "bookmatch" the core. Not sure if this really makes a difference but it appeals to me, so I do it.

Good tip on the Mill hafte, my router bit does indeed tend to mangle things.
- Ben
Greg
Posts: 225
Joined: Thu May 26, 2005 11:41 am
Location: Sweden but home is NW Washington

Post by Greg »

I usually use this method as well. I have also done it with 2X6's, and was able to make 2 pairs of skis out of 2 ash 2x6's.

Lately though, I have been experimenting with making cores out of 1x6's. And not laminating anything. I just put a 1x6 in my profiler and then make it into a ski. I haven't actually skied these yet, so I have no idea how well they will work, but this method cuts the building process in half.

Next, I am going to experiment with using vertical grain douglas fir. You can buy it at the lumber yard in (true) 1/2 inch thick pieces and 6 inch widths, which would save a huge amount of energy. And, hopefully, having the vertical grain will produce the same effect as laminating several pieces of wood together. Not to mention the reduction in wasted material.
Cadman

Post by Cadman »

Using solid wood for cores is simple but can cause problems when trying
to get both skis to flex the same. Different growing rings with woods can make one piece soft and the other stiff. Knots and other little imperfections and grain angle will also make the flex different from one piece of wood to the next one. That is the reason why ski manufacturers went to the vertically laminated cores because it made the delta between stiff and soft less so there was not such a difference stiffeness between skis. It made for more uniform flex in the skis.

From my experience I have found that micro laminate cores ( 3mm wide
strips) seem to feel more solid than the wider laminates such as the kind that they use to make snowboards. The wide laminates feel like skis they made in the 70's with kind of a "tinny" sound to them when you get them on harder snow. That could be resins or lack of damping layers too. I am not sure here. Maybe someone with more composite experience could comment here.

So if you are going to use solid cores, I would make more than the two for each ski and make some kind of weight that you can hang from each core and measure the deflection to match up cores so you can hopefully get a closer match when they are finished.
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