snapping tip spacer joints left and right

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goneskiing
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Post by goneskiing »

i'm in golden, right outside of denver. and yeah the braider is +-60 and 0. knights of nii i'm definately going to, i started on my new core design last night. thank you guys a lot for the input, you deffinately put my mind at ease and gave me some good things to think about
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MontuckyMadman
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Post by MontuckyMadman »

Don't believe everything you read on the internet posted by some yahoooo.
sammer wrote: I'm still a tang on top guy.
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skimann20
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Post by skimann20 »

MontuckyMadman wrote:Don't believe everything you read on the internet posted by some yahoooo.
ooooo so true MM. ;) can I request that you get a new avatar this year? all i see is Admiral Ackbar every time i look at it. not saying thats a bad thing it just messes with my mind...
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vinman
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Post by vinman »

For your delam under the core....are you using VDS? What type of sidewall? If Ptex are you abrading and flaming it properly?

Are you getting too much pressure in the tips with too much squeeze out creating a dry spot and a poor bond? Maybe the reason for so much resin?
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goneskiing
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Joined: Fri Aug 10, 2012 9:25 pm

Post by goneskiing »

yeah i've been using the vds, but wasn't rabbeting the core out for my edges....maybe it was causing too much pressure on that area and i was losing all the epoxy? since i've just been prototyping different flex patterns i haven't been using sidewalls at all, just laminating together my core materials and leaving them square. wood sidewalls.

i always read about you guys discussing the proper ration of fabric to resin. i should try that approach also instead of just the "this should be good" approcach. i guess my only question is how do you measure out a ratio of 70/30 fabric to resin? is it as simple as placing my fabrics on the scale beforehand and literally just doing the math to figure out my resins? hopefully thats not such an a blatently stupid quesion.
Richuk
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Post by Richuk »

The amount of resin required for a specific fraction can be determined using a FVF calulator:

http://www.netcomposites.com/calculator ... -fractions

The final number should include an additional amount for waste and adhesion to the wood core. For good adhesion, you need a core with a moisture content of around 7%. You don't want moisture from the core interacting with the resin.

I wouldn't rely on your press to deliver the defined resin ratio. The first practical step is to build a resin impregator or something along those lines ... it can be done quite simply using printing rollers. Ideally, the roller should be 2 inch diameter.

Oh, not sure rebatting is the best method ... have a look at what Twizz did to resolve this issue.

If you haven't done so alreay, it's worth reading Springer:

http://www.skibuilders.com/phpBB2/viewtopic.php?t=4304

Second to last link. It might take a while to digest, but worth knowing.
goneskiing
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Post by goneskiing »

much appreciated! thanks for the info, thats a big help
rockaukum
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Post by rockaukum »

I had a problem with the cracking across the tip spacer and core line. I cut straight across. My problem with this set of skis was that I did not overlap the joint with the skis edging. In other words the edge stopped before the joint. It is my belief that if the edge were to overlap the joint between tip spacer and core you will have a much stronger ski.
Keeping in mind that I am not a engineer and do look at things from a logical perspective. This is backed up with lots of reading around here too...
ra
rockaukum
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Location: Placerville area

Post by rockaukum »

I had a problem with the cracking across the tip spacer and core line. I cut straight across. My problem with this set of skis was that I did not overlap the joint with the skis edging. In other words the edge stopped before the joint. It is my belief that if the edge were to overlap the joint between tip spacer and core you will have a much stronger ski.
Keeping in mind that I am not a engineer and do look at things from a logical perspective. This is backed up with lots of reading around here too...
ra
knightsofnii
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Post by knightsofnii »

After reading this again, I'm going to change my own design.

My sidewall ends and butts into my tipfill... my tip fill goes into my core an extra inch more than the thickness of the sidewall...

I suspect this is a large enough seam that a load on the nose/tail great enough has caused some delams for us.

I think I'm going to try to make the joint at an angle and stagger it, and change the tip fill shape
Doug
skidesmond
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Post by skidesmond »

I too re-read this post and just wanted to comment that on my skis, I make the sure the steel edges go past the seam where the tip fill and core meet or you can do a full wrap. Also the start of the bend for the tip should not be on the seam of the tip fill and core.
knightsofnii
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Post by knightsofnii »

^ more good tips :)


and... if you do a two piece tip fill, for sake of saving plastic on your sheet of plastic...

don't lay the tip fill seam in the same spot as the edge seam. I always skew my edge seam about 5 teeth right or left, because i dont want the seam right were someone's gonna rest the board on the ground, or bang it into something, the tippy tip of nose/tail very prone to impact.
Doug
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