Core Q's-Does 1 mil diffenence change my world? Help

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Wannabebuilder
Posts: 60
Joined: Sat Oct 20, 2007 8:22 am

Core Q's-Does 1 mil diffenence change my world? Help

Post by Wannabebuilder »

So, the front end ie: tip part of my profiling jig rails are not even. When I profiled there is a 1 mil difference across the core laterally. So it will probably flex differently from inside to outside edge in the tip.
Should I a) belt sand as close as I can to make it more even?
I'm afraid I will make both cores more different and thus make to completely differently flexing skis.
B) ignore it the glass/resin will pick up the difference.
or
C) something I don't know cause I don't know what I am doing.

Just for the record this is a RR pow ski.
139 at the waist, rocker in the tip. Pin tip and tail. 1mm of sidecut underfoot.
think d.p.s.

core is poplar
base,edge
rubber
triax
core
triax
power triax strip in the rear
cloth topsheet

Oh yeah I think the cores are to thin at 10mm even taper to 2.2mm at the tip and tail. I meant to make them 12 don't know what happened.
Apparently I have trouble making 2 even profile rails.
I think what happened is they were uneven so I sanded to make them even and failed in the front part of the rail as well as took off 2mm while sanding.
Blahhhh.. I have wasted like 50 bucks in wood already.
kelvin
Site Admin
Posts: 262
Joined: Thu Feb 03, 2005 4:56 pm
Location: Jackson Hole

Post by kelvin »

a small change in thickness makes a big change in stiffness. 10mm is pretty thin and would probably make a soft ski. But for powder, it might be good.

One thing to watch for is that your router bridge is not flexing. As you push down on the router, it could flex the bridge and cause different thicknesses.

-kelvin
rockaukum
Posts: 561
Joined: Fri Nov 03, 2006 9:23 am
Location: Placerville area

Post by rockaukum »

I'd second that on the thickness. However that being said, I have a set that is 10 underfoot and sure enjoyed it in the soft stuff. did it on purpose for a lighter bc ski.
ra
Wannabebuilder
Posts: 60
Joined: Sat Oct 20, 2007 8:22 am

Post by Wannabebuilder »

Thanks guys.
The bridge is not flexing just my inability to make the two rails uniform.
Damnit I want it stiff cause it will have a fair amount of rocker. I kinda thought at 138mm at the waist a 10mm thickness underfoot would be alright.
Nick's Sticks
Posts: 105
Joined: Fri Sep 08, 2006 9:15 am
Location: Cascadia

Post by Nick's Sticks »

Here is an old boat building trick. Try cutting your pieces at the same time. In boat building it is more important to have matching pieces than it is to have perfect curves. If port and starboard are flawed equally it isn't really a big deal. Stack your rails together and cut them together. If you mess up at least they will still be even. It saves time and you don't have to worry about cutting exactly the same twice.

I try to do all my shaping together. I built my planer jig to profile both cores at once and I cut both left and right ski bases at the same time. Good luck.
krp8128
Posts: 367
Joined: Fri Feb 23, 2007 1:57 pm
Location: Marcellus, NY

Post by krp8128 »

Nick's Sticks wrote:Here is an old boat building trick. Try cutting your pieces at the same time. In boat building it is more important to have matching pieces than it is to have perfect curves. If port and starboard are flawed equally it isn't really a big deal. Stack your rails together and cut them together. If you mess up at least they will still be even. It saves time and you don't have to worry about cutting exactly the same twice.

I try to do all my shaping together. I built my planer jig to profile both cores at once and I cut both left and right ski bases at the same time. Good luck.
Cut 1 out, sand it all pretty and such. Then rough cut a 2nd, attach it to the 1st and use a router with a flush trim bit. 2 exact parts.
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