Loss of Camber after Stone Grind?

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Skivolkl
Posts: 22
Joined: Fri Dec 23, 2005 7:40 am
Location: Madison, WI

Loss of Camber after Stone Grind?

Post by Skivolkl »

I have made several pairs of skis and none of them have loss their camber after I have taken them out of the mold. The last pair of skis I made had all of it's camber when I took it out of the mold. I let the skis cure for a week before taking them to a local ski shop for a stone grind. Before the stone grind the skis still had their camber, after the grind the skis lost some off their camber. I have put about twelve days of riding time on them since and they haven't lost anymore camber. The loss of camber has moved the contact points about 6 inches toward the center of the ski from the tips and tails. The skis still ski pretty good but is seems that they have a smaller sweet spot. Just wondering if any of you have had similar problems or have any advice?

o0norton0o
Posts: 12
Joined: Tue Mar 14, 2006 10:07 am
Location: Seattle

Post by o0norton0o »

hi to everyone, I am new here so I will tread as lightly as possible to begin with. I have been milling my own lumber for many years and sometimes lumber has tension in it. Also after machining lumber it may release tension slowly. I have seen a straight board that when ripped in half now becomes two crooked boards. This is called unwinding and is common to all lumber in varying degrees based on species and grain angles. Quartered lumber unwinds the best since it has a grain that aligns with the matrix of the ski construction. balancing the core glue up angles to opose each other is a common technique for "bricklaying" most glue up processes and counteracting lumber tension... I digress sorry.
Perhaps you had some core material that released its tension slowly to shorten your sweet spot. Common joinery techniques to prevent that are to resaw oversize, then join two adjacent sides perpendicularly and let it unwind for a few days slightly over the required finished size , then rejoin and surface to size. No one does this by the way (too time consuming), so if you join something the first time and it reacts badly, just disgard it... or even better is to incorporate the tension into the ski in a beneficial way. Obviously you had better know what "benficial" would be for ski construction. I am new to those nuances of ski construction, but am hoping to make a truly crazy pair of tele-skis... maybe a "scotty bob" type clone. I am open to the experianced builders input here. GREAT SITE!!!
norton
est sularis oth mithas

Greg
Posts: 225
Joined: Thu May 26, 2005 11:41 am
Location: Sweden but home is NW Washington

Post by Greg »

I to have had those issues when doing woodworking. And, I think you are dead on in that grinding material off of the base removes material that is in tension (the base) and allows the remaining base material to stretch more. This would cause the reduction in camber that you saw, but it sounds like you had pretty good bonding if you didn't lose anymore camber later on.

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