No wind for a long time so have been keeping distracted by trying some thing new in my latest twin tip project 'The Stubby'
Its short and wide at 130 x 43.5cm because in the local light conditions I find that its the width and not length has the biggest impact on early planing. Its 100% basalt fibre this time, 3 layers of 200 gm top and bottom. With a bit of elbow grease and clear coat at the end the metallic luster of the basalt really comes through.
Instead of thinning the core smoothly as you move towards the tips I staggered the lengths of planks in the balsa top deck to get the same net affect but with a pixelated look:) Rest of the core is 6mm Paulownia and 4mm ABS rails all inserts are 6mm stainless steel nuts encapsulated in epoxy.
40mm of rocker that follows an elliptical curve that matches the profile of a heavy flexible plank bending under its own weight. The same profile I used in the last board (but 50mm rocker in last one) and no complaints at all. Having a good helping of rocker saved me from digging the nose in countless times especially in the surf. The 50mm of rocker was awesome in the surf - could just ride straight at a wall of white water and the rocker worked like an elevator. The downside was when you jammed the rail in the board wanted to carve upwind instead of grip. Great for tricks where you can use lots of rotational speed but not good for most other things. Hoping that 40mm is a happy middle ground.
This was the major experiment - big mofo channels in the hope I can cut the fins way down and still grip in the surf. This was a real construction challenge because normally you lay the board up by vacuum pressing it onto the rocker table surface. Without channels or a mould to press the channels into, getting 3D shaping top and bottom is tough and blows out the time to make it. I ended up making the bottom skins with the channels and 2 layers of basalt first. Then in a separate step a few days later I put a foam support under the channels and layed up the rest of the board as normal. This basically doubled the time to finish it off. Next time round I'm going to try making the board with the top side on the rocker table.
Anyhow it turned out well and hoping that the 6mm exo-channel pieces can lock it in even without fins.
Anyhow, full build details at www.boardbuilders.co
[URL]boardbuilders-forum.1077691.n5.nabble.com/The-Stubby-130x43cm-freestyle-board-td1455.html[/URL]
Now just need some wind to put it through its paces.
Matt
i allways believed deep channels didnt help grip they just made the board more dragy (more slowing then hard edgeing) spoke to some fluid dynamics guru about it one day do you look at that sort of thing when designing your boards?
O for awesome!
Hows the flex? is basalt closer to glass than carbon for stiffness?
Does basalt give any performance advantage over glass or carbon? better wear resistance perhaps? or simply cool factor.
Select to expand quotePlummet said...
Does basalt give any performance advantage over glass or carbon?
Yes.
Select to expand quotedecay said... Plummet said...
Does basalt give any performance advantage over glass or carbon?
Yes.
What?
Select to expand quotePlummet said... decay said...
Plummet said...
Does basalt give any performance advantage over glass or carbon?
Yes.
What?
That answer will be provided in my Cabrinha 2015 Board Tech videos, due out in less than a month... 
I think StickFlick is riding his basalt boards for quite a while and got all answers already;)
Select to expand quotedaggy said...
bung on some bright red fins or you're gonna loose that sucker in the surf
Believe or not I had red ( well orange) fins on it first but opted for mis-understood black:) My last basalt board was same colors and the black turned out to be pretty easy to spot because in the surf because its sticks out in the white wash.
Select to expand quotedecay said... Plummet said...
Does basalt give any performance advantage over glass or carbon?
Yes.
there is no cool factor for carbon basalt plummet its cheaper to make then carbon fibre and gives simular tho i believe less effective results. do a quick wikipedia on it.
Select to expand quotekookaburrahz said...
i allways believed deep channels didnt help grip they just made the board more dragy (more slowing then hard edgeing) spoke to some fluid dynamics guru about it one day do you look at that sort of thing when designing your boards?
Hey Kookaburrahz,
Its definitely is something I put some thought into because it’s not just channels but also the rocker and concave and how rough the surface finish is on the board plus the outline all contribute to one or more parts of the different types of drag. And the impact of drag on performance, I find, is really noticeable in light conditions and also the top speed you can get out of your board.
I think you’re right that channels will increase drag if everything else about the board and the way you ride it remains the same. When you think about it a channel is like a very elongated fin and in the same way bigger fins create more drag so so channels. The reason though that’s its so hard to say that this is categorically true for a board is that the things that a fluid dynamics guy would come up may not take into account how things like drag and lift feed back into the way you ride the board which in turn changes the values of the drag and the lift and so on back and forth. This is in part why prototyping is such a critical part of board design and why there is so much art and to board design.
I’ve found with riding channeled boards with the channels concentrated in the middle section that I can use much smaller fins – less drag - and can ride the board flatter (less edge) and ridden this way the light wind performance and speed seemed on a par with similar boards I was try ( bear in mind it’s a small sample I’m drawing on).
However, there are a few other reasons in the pro’s and cons mix that I think channels add to the story: a good weight vs stiffness trade off, softening landings and better grip when you land without being able to get the rail in as hard as you like.
The weight vs stiffness is a really interesting one and one that Lars Molle at Naish talks about a lot in his pursuit of ever lighter and stronger boards. Based on some back of the envelop calcs, if you bend a piece of core material to create the channel and make the channel as deep as the material is thick then you roughly double the stiffness of it. You basically get this for free with no weight being added. It also has the added benefit that the stiffness from the laminate increases greatly too (to see this just take a playing card and bend it down the long axis and then try and bend it on the short axis which is nearly impossible). This is the same thing that concave does to stiffness.
An interesting side note on the science of design (not the material science part, just the design part) - I was talking to a mate in NZ whose involved in making world class carbon windsurfers and he told me about a Ph.D some guy in the US did on really detailed modelling and measurement in a lab setting for windsurfers. Great data, great engineering models but it went nowhere because it was impossible to translate the science into the feel in any meaningful way – again , for me at least, reiterates the importance of the art, craftsmanship and prototyping in building boards.
Sorry for the long post but this is an area that really fascinates me.
Cheers
matt
Select to expand quote said..decay said... Plummet said...
Does basalt give any performance advantage over glass or carbon?
Yes.
there is no cool factor for carbon basalt plummet its cheaper to make then carbon fibre and gives simular tho i believe less effective results. do a quick wikipedia on it.
On the material properties front carbon is stronger which means you can get a a strong stiffer board with carbon. Different source say that some carbon fibre is 25-40% stronger than basalt. However, there are a few things that in practice reduce the size of the difference. Plus or minus a typical laminate has as much epoxy as it does reinforcement material and epoxy is very weak relative to both. When you mix them you average the strength down so this closes the gap a bit. Unless the epoxy/laminate mix close to the money its more likely that the epoxy component of the laminate will fail first so you may never reach the theoretic limit of the strength in either in which case its a moot point. None of this changes the fact that carbon is stronger but the gap in the properties is probably much less in practice.
The nice property of Basalt that is does have over carbon is how much it will stretch before it breaks. Most of the data I've seen on carbon that I can get hold of (i.e. small quantities) has its elongation before breaking at around 1% - breaks after its length extends by 1 %. Basalt is most often quoted at greater than 3%. Although this sounds small, in terms of the amount the fibres elongate in the typical flex in a board the factor of 3 difference is very material and I'm guessing might make it necessary to over engineer a carbon board to make sure it doesn't go outside its operating range. Carbon is also typically quoted at being twice as stiff. So carbon is stronger but stiffer and breaks sooner in applications where is subjected to lots of flexing - brittle you could say. I can't help thinking that mixing the two might be a great option. Carbon in middle section of board to lock in the rocker and make sure it works as intended and basalt on the tips where you want it flex.
As Kookaburraz said it is cheaper. I only buy small quantities ( 10m ) and I think I paid around $27 /m for 1.2m wide basalt. The same in carbon in similar quantities and weights i think was closer to $50.
Carbon definitely is sexier. When Basalt's not being metallic/brassy its brown and there is no way around it. It needs sexing up or covering up.
A small but important point in a market where technology/design seem to be maturing is that basalt has much better green credentials that carbon and fibre glass. None are good, its all very energy intensive to make them but basalt is molten quarried basalt with no artificial coloring or flavours and the pollution from producing it, as I understand, is mostly that of the energy production for melt it and not the stuff that goes in or comes off it. The metallic tint is because of the metallic components in basalt.
The story around basalt might be different in a production environment where longevity and it production qualities are more critical and I'll be very keen to hear from Decay when the Cabrihna products go live to see how he sees it. I saw that they had used basalt in a wake board last year so it seems the experiment worked out.
Decay, anything you can share with us now before the launch?
Matt
More than you wanted to know about Basalt.
" ... offer performance similar to S-2 glass fibers at a price point between S-2 glass and E-glass, and may offer manufacturers a less-expensive alternative to carbon fiber for products in which the latter represents over-engineering."
[URL]www.compositesworld.com/articles/basalt-fibers-alternative-to-glass[/URL]
Ultimately it should mean higher performance boards are cheaper to produce without compromising the strength where its actually needed. Remains to be seen if this translates into cheaper boards or more expensive booze at team rider parties 
