Section8 2012-2013

sammer · Post by **sammer** » Sun Nov 18, 2012 10:58 am

I've made up a few templates from left over strips of mdf with different radii
Cores get screwed together and rough rough cut with the jig saw.
Then the template gets screwed to the cores and traced on the router table.
You pretty much have to work from tip to waist and tail to waist, climb cutting where necessary, Or the chance of tearout is pretty high.

Pic shows the 22m radius template screwed to the latest fat cores.
After routing one side the template gets flipped to do the other side.

As every different ski has a different width I have to figure out where the screws holes need to be to cut off the require amount and have a little overhang when the sidewalls get glued on.
That's why there are all the marked holes in the template.
The template can be made with snocad, just make your running length really long.

You can fudge a bit using the 22m template for a few different radii, just have to make your sidewalls a little wider or narrower.

This saves a fair bit of time shaping cores.

Wow long explanation for a simple device.
I've been planning on putting together a core howto post for a while, Just have to find the time and drive

sam

skidesmond · Post by **skidesmond** » Sun Nov 18, 2012 2:16 pm

Great tip Sammer! I was using for base template that I had CNC'ed to shape the wood core. I new if I screwed up and gouged the template I'm out the cost of a CNC'ed template, ouch. I new I had to come up with a better approach.

I like your approach, nice and simple. Sometimes I over think things. I think I'll make a handle full of "core templates" using SnoCad-X .

The other slight problem I encountered using my base templates as core templates is that they are made for 3/4 wrap edges. That was another minor hassle.

When you start routing material that exceeds 1/2 the width of the router bit, expect tear out. The excess material will start to vibrate and interfere with the bit. Next thing you know you got kindling wood.

vinman · Post by **vinman** » Sun Nov 18, 2012 2:43 pm

Here is my method.

Subtract the sidewall width from the overall ski width (including base +edges)

Full ski dimensions -( sidewall width x2) = core width, repeat for each dimension you want to measure.

Divide these measurements in half = 1/2 width.

Draw center line on core. Place your tape with the 1/2 width mark on the center line. Mark 0 and your full core width. Repeat for each dimension.

Line up the template on your marks and draw out your shape. Rough cut with jig saw. Shape with belt sander to line. Recheck dimensions.

Glue on sidewalls.

skidesmond · Post by **skidesmond** » Sun Nov 18, 2012 5:18 pm

That's basically how I figured the dimensions as well. The tricky part came when I thought I could plow the router through the excess material. The router is powerful enough (3hp) but the excess material is what caused the core to break off. Not a disaster by any means, just an inconvenience.

skidesmond · Post by **skidesmond** » Thu Nov 22, 2012 9:30 am

I got the cores made, 3-11-3. Got the cores to match weight wise. That's a first! After profiling with the planer there was a 10 gram difference, 5 minutes of sanding with 80 grit I got them to match, 872 grams each w/o tip and tail spacer. The tip spacer will be 2 layers of poplar veneer. Tail spacer will be from Ipe scraps. Ipe is pretty heavy. I figure about 1/4-1/3 of the Ipe will be cut off in the flashing/trimming process.

Think I'll clean the shop now and then call it a day.

Happy Thanksgiving to all!

falls · Post by **falls** » Fri Nov 23, 2012 1:29 am

If you use a wider diameter template router bit you should have less problems with tear out in your cores.

My last pair of cores I made were 100 grams different after profiling! I measured them both every 10cm and they were pretty much identical measurements. Different bamboo densities from one board to the next? Its always something!

Richuk · Post by **Richuk** » Fri Nov 23, 2012 3:09 am

Part of the difference could be moisture content Falls.

skidesmond · Post by **skidesmond** » Fri Nov 23, 2012 4:16 am

Falls/Rich, This is the first time I weighed the cores before layup, it was more out of curiosity. I was surprised that 10 gram (.35 oz.) difference, thought that was pretty small. I also took measurements at the key points. They weren't exact, like .1-.2mm difference in spots.

Pretty happy overall.

Richuk · Post by **Richuk** » Fri Nov 23, 2012 2:31 pm

Sounds like quality!

falls · Post by **falls** » Fri Nov 23, 2012 9:23 pm

good thought Rich
after flashing they are 115g different - so only a 15g difference in the layup process I am pretty happy with. Just not the overall 115g difference. Like to keep it under 40g.
I think I will measure and weigh the original boards for each core before the next pair.

thread hijack - sorry

skidesmond · Post by **skidesmond** » Sat Nov 24, 2012 3:17 am

^^^ Nah, not really, we're still talking about quality.

vinman · Post by **vinman** » Sat Nov 24, 2012 4:09 am

My best was 1/8 oz or 3.5g different in the finished ski. But typically I am around 1/2 to 1.5 oz Difference between skis within a pair.

skidesmond · Post by **skidesmond** » Sat Nov 24, 2012 9:10 am

That's great. I don't think anyone would know the different of a 1 or 2 ounces. Heck, once you're moving on the snow you have uneven weight because of snow on the skis and boots. But it good to strive for excellence.

MontuckyMadman · Post by **MontuckyMadman** » Sat Nov 24, 2012 6:45 pm

not to toot my own horn but we have been getting skis taht weigh almost exactly teh same within a few grams.

skidesmond · Post by **skidesmond** » Sat Dec 01, 2012 2:25 pm

Slight detour from the current build. I pulled the Dia dellos Muertos skis out today and added some bling to the eyes of the skulls and added glitter to the epoxy for grins. I think the crystals will be standard.

http://desmondcustomskis.blogspot.com/2 ... eason.html

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Section8 2012-2013