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skidesmond
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Post by skidesmond »

Nice! What kind of veneer is the top sheet?

I went back to the start of the build.... not bad, started in may with the press and made your first board in august. Way to go!

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MontuckyMadman
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Post by MontuckyMadman »

really nice work. Great Job!

Carbon reinforced rubber sounds bad to me as an edge gasket.
As I understand the rubber gives a semi flexible shear layer between two very hard things, edge and resin/glass.

I would think the carbon would make the rubber very ridged and eliminate the shear effect. Or lack of shear. dunno.

Am I off here?

Alex13
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Post by Alex13 »

Montucky - to be honest I'm not sure. I bought "vds" from a forum user here, and that's what I was sent in the mail (see pic). Maybe the VDS is the brown roll (also in the pic with the roll of carbon rubber) and I was confused - I've never seen VDS before so had nothing to compare against. I assumed the carbon reinforced rubber was a substitute or the same stuff.

It seems to have stuck alright, I may cut up the flash where it overhangs to see how strong the bond is.

Desmond - the veneer is Silky Oak. I'm thinking about experimenting with veneers a fair bit for top sheets, making designs out of different woods etc. I found a site on joining veneers here for those interested: http://www.joewoodworker.com/veneering/veneertaping.htm

Board has been cut out, routed (poorly, but sanded up ok) and sent for a base grind. My camera ran out of juice before I got a pic, but will post one up when it's all ground up.

Good news is, the blokes at the snowboard shop were all over it, I got flooded with questions. Had a couple asking to test prototypes in future, and the shop owner is keen to stock a couple boards if/when I move into production :)

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MontuckyMadman
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Post by MontuckyMadman »

thats awesome usually the shop dudes love that stuff.
The vds is definitely the tanish yellow roll. the carbon reinforced rubber, I have no idea, sounds awesome though. It just seemed a little counter intuitive. maybe I am over thinking it. Ride it, flex it hard and allot and see what happens.

So who did you get the carbon rubber from lets ask them?

Congrats on allot of hard wok done well.
Image

Alex13
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Post by Alex13 »

There you go. I wonder if the carbon rubber I've used has contributed much to the stiffness of the board. Using only Paulownia and glass, I expected it to be fairly flexy, but it's nice and stiff.

I'll build my next few boards with the carbon in the same place, I need to for consistency in my thesis, but I may build a test board with the VDS as well to see the difference. I've got enough materials for 10 boards of this shape, so may as well use them.

skidesmond
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Post by skidesmond »

Alex13 wrote: I'm thinking about experimenting with veneers a fair bit for top sheets, making designs out of different woods etc. I found a site on joining veneers here for those interested: http://www.joewoodworker.com/veneering/veneertaping.htm
I had a similar thought about veneers. I'm saving the cutoffs from the veneers I have and will make like a patch work of different random patterns.

Take a look at www.scottybob.com for some real fancy veneer work. Looks like it's marquetry style.

Alex13
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Post by Alex13 »

Well I've figured out the mystery of the "carbon fibre rubber roll". It turns out it's uni directional carbon fibre, no rubber at all.

My confusion stems from the fact that it appears I was sent the carbon by accident, and on the box it says "carbon fibre rubber roll" which actually means "carbon fibre, rubber roll" as two separate items in the packaging.

In the fleecy stuff it's bound in, you can't see any individual fibres, it just looks like solid black stuff.

I'll need to redo my reference board, but should be an interesting test board nonetheless with super stiff edges and minimal torsional stiffness! Hahaha. I must admit I feel a little stupid not spotting the difference between uni directional carbon and rubber!

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SHIF
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Post by SHIF »

Alex, You're quite lucky. You bought uni-carbon for the price of rubber.

How much do you have?
Last edited by SHIF on Mon Aug 23, 2010 10:33 pm, edited 1 time in total.

Alex13
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Post by Alex13 »

1800' (550m) of 1" wide on the roll it appears. I contacted the bloke I bought it off and have arranged to pay for it, albeit at a reduced price.

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SHIF
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Post by SHIF »

Very cool, and still a sweet deal. You will find that adding unidirectional carbon fiber below (and above) the core really stiffens the flex. An effect as dramatic as varying the core thickness. Plus it adds "pop" to the ski or board, a lot of energy.

Keep up the good work.

Richuk
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Post by Richuk »

Hi Alex,

You might already have these, but I came across them when doing a bit of research on vibration dampening.

http://www.wagnerskis.com/blog/2008/ene ... n-and-pop/

http://www.omaticsnowboards.com/wordpress/tech.html

http://digital.library.okstate.edu/OAS/ ... 98_101.pdf

Alex13
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Post by Alex13 »

I haven't seen those before Richuk, thanks for the info. The more the merrier!

Tomorrow - setting up the laser vibrometer for a test run on this board!

carnold
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Post by carnold »

Better hurry with all that rain comming!!

Alex13
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Post by Alex13 »

I know. It sucks. Nothing I can do now though, still waiting on CNC.

Alex13
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Post by Alex13 »

So I've had a busy week, 3 boards out since yesterday morning.

Good thing is I'm getting better at bending edges by hand. They still aren't perfect but they are much better, especially on this 3rd board (in the press now).

The 3rd board should be interesting, it has VDS running in the direction of the 2nd torsional mode, which is basically from the widest part of the tip, through in a straight line to the centre of the board, then through to the widest part of the tail, on both sides. I'll put up a pic later. I put the VDS under the core. I'll be testing whether it has any discernable damping effect in the sub-100Hz range (which is the important range for undesirable vibrations).

The 2nd board is the same, but with carbon in those directions, and placed above the core. I did this to limit the effect the carbon would have, as I believe it will be fairly stiff.

The first is the reference board, which is just a straight glass layup, no unusual additions.

I'll be making another board tomorrow with both carbon and VDS (aside from just on the edges) in the layup.

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