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 Post subject: Re: Alternative to breaking surfboards
PostPosted: Sat Aug 31, 2013 5:46 pm 
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no board is unbreakable as we know but check out Doyle boards
made in the gorge and as strong as anything out there and still rides great


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 Post subject: Re: Alternative to breaking surfboards
PostPosted: Sun Sep 01, 2013 11:47 am 
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Dude you gotta show us what you're breaking and how your're breaking em.....small crack where and from what cause?

If these are from rocks, transport, or harness dings in what are typically unstressed, unreinforced areas you need to carry a tube of ding stick to get more life from board.

Secondly, strapped or strapless?
strapped you can get away with more weight
strapless I find once I get in the 8+lb range the boards are BOMBPROOF but tend to fall away from your feet on strapless airs unless you point them REALLY high into the wind.
6lb is the magic range for me and I'm willing to sacrifice some toughness for this.

Local shaper has the capability to kick the hell out of production board in terms of weight AND durability, they can take the time to take extra labour intensive steps to add reinforcement where you need it and use higher cost materials that are not practical in a production environment.

From my conversations with shapers, and the stuff posted on their websites from a structures perspective many shapers (not all) don't really understand exactly what's going on simple things like the difference between strength, stiffness and impact resistance are oftentimes not well understood. Especially if you deviate from their proven "recipe"

They'll make a board "stronger" by taking their recipe and adding more shit (Carbon Kevlar glass, wood HD foam) but you may end up with a board that is heavier stiffer and still not as tough as you wanted or with marginal improvements to the "strength" you actually need.


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 Post subject: Re: Alternative to breaking surfboards
PostPosted: Sun Sep 01, 2013 6:08 pm 
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BWD wrote:
I vote for the local the shaper, followed by the mutant.
I've made a skim (not into it, too short), an alaia, a flat/wide directional, and latest a thing modeled pretty much after the BRM paipo board.
I gave the paipo thing a little more outline curve but kept the little TT fins. Works great.
It should hold up fine, 18oz glass over wood core.
No straps but that could be done, as could surfboard fins....

I saw your posts over at Swaylocks.
Post a pic of your Paipo thing, it looks great.


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 Post subject: Re: Alternative to breaking surfboards
PostPosted: Mon Sep 02, 2013 4:50 am 
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Johnny Rotten wrote:
Dude you gotta show us what you're breaking and how your're breaking em.....small crack where and from what cause?

....


I have had two kinds of failures over three boards.

One board cracked under the front foot from a vertical descent to a hard landing. It was repaired and cracked again. A major structural repair was done and it cracked again and I gave up on it. The subsequent crack came from the repeated slamming of the board over chop.

The major reconstruction included more glass under the front foot. All that seemed to do was transfer the force to the edge of the glass reinforcement so it cracked there.

Two boards appear to have leaked around one of the thruster fin boxes (both Futures boxes, one heel side, one toe side). There are no visible cracks around the fin boxes but the water stains can be seen in this area.

The last board to die was stuffed. The foam core had serious cancer. I could press the water damaged bit in with a finger and flex the fin box from side to side. It was kind of fun to ride it around over coral not really caring if it got damaged and it died on the last day of a kiting holiday so I was pretty happy at the time.

These boards have been ridden hard and ridden a lot. I jump a fair bit but the vast majority of landings are silky smooth. Possibly the worst they get is a lot of toe side pops with float landings. I've started turning them into air gybes and that smooths out the landing a little.

I've been thinking that I sometimes drop the boards fins down onto the sand or grass. It's only a foot or so and I don't know if it causes damage, but my instincts are telling me to avoid that in future.

I wouldn't care if the boards broke from a major impact or clobbering. It's more annoying that they wear out after 100 hours or so. My TT boards have 300-400 hours each and they're good as new.

My only concern about the local shaper is that I suspect his approach will be to simply add more layers of glass to make a stronger board. He does a shitload of repair work on epoxy boards so hopefully he knows what he is doing in that area.


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 Post subject: Re: Alternative to breaking surfboards
PostPosted: Mon Sep 02, 2013 7:04 am 
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Ozbungy,

As you've found, patches of any description rarely work.

The problem is that we are all after the magic combination of lightest weight, highest strength and great flex characteristics and they are all (almost) polar opposites, especially when you ad pricing into the mix.

It sounds like the problem you are experiencing (I don't know what boards they are, so I'm off the hook there :-) ) is that the EPS core is just too light for you.
Some guys use an EPS core as light as 16kg/m3 and then think that throwing a layer of 0.3mm bamboo into the layup mix will suffice, but that's only good enough if you are super light on your boards, and with this core weight the fin boxes and inserts need to be re-enforced with corecell (or similar) blocks or you will experience the type of fin box issues that you mention.

The problem is that the EPS core compresses under the pressure of normal use, and once there is any degradation of the core the outer layup will fracture as it over flexes or fatigues at that point where there is no longer any structural support..

You need to look for board with a higher density EPS, somewhere around 20-23kg/m3 or preferably (IMO) a higher density PU core.
The PU cores are a little heavier but they tend to develop "heel dents" rather than actually crack through the layup and in the end this translates into a longer lasting board, albeit that they will be heavier than your current board.

There just is no way around the weight/durability issue unless you are prepared to start introducing more exotic materials into the mix, along with the accompanying price tag, and then even this is 100% dependant on the materials being applied in the correct manner.

What you need is a good board builder, which is not always the same as a good shaper, and if you can find one that can do both then you have a winner :-)


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 Post subject: Re: Alternative to breaking surfboards
PostPosted: Mon Sep 02, 2013 2:53 pm 
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Ok here it is
Not really a surfboard, kind of interesting as an alternative though


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 Post subject: Re: Alternative to breaking surfboards
PostPosted: Mon Sep 02, 2013 11:38 pm 
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Location: Save a life...adopt a Pitbull
Looks great! :thumb:
Would like to have exact dimensions and rocker details.
PM if you would like to pass on more detail.
Thanks.


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 Post subject: Re: Alternative to breaking surfboards
PostPosted: Tue Sep 03, 2013 3:06 am 
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OzBungy wrote:
I have had two kinds of failures over three boards.


Two boards appear to have leaked around one of the thruster fin boxes (both Futures boxes, one heel side, one toe side). There are no visible cracks around the fin boxes but the water stains can be seen in this area.






FINS!
easy problem solid divinycell H80ish jammed into the core from top skin to bottom skin. In the area in and around the fin boxes. put it in before shaping. once shaped, it adds very little weight, is closed cell (waterproof) and takes a beating. I'll see if I can find a pic of my build. will have to shape with a router or planer though, sanding will not work well.
Also gives you mad dent resistance in the rear foot area.

I ALWAYS bash my fins on crap when I ride. Was always breaking fins so I started making my own solid G10 probox fins.... Now I just get ejected....... or rip the set screws clean out of the plastic fin box .....(can be repaired epoxy milled glass and a few pieces of carbon tow) regardless infinitely fewer failures and NO LEAKS.

S A wrote:

The problem is that we are all after the magic combination of lightest weight, highest strength and great flex characteristics and they are all (almost) polar opposites, especially when you ad pricing into the mix

.
.
S glass has the best flex, (lowest young's modulus) almost identical strength (Ultimate tensile strength) AND the best toughness(drop test results....most relevant to kiteboarding) as well as being the lowest priced of carbon or Kevlar.....
It is a far better material choice for surfboards

As for core crush. This has to be designed into the sandwhich, The EPS core is pretty useless against a point load. So the sandwhich structural foam is there in combination with glass to create a beam to protect it.
I really wanna work out the calcs and weights of a hollow board I suspect if you took the weight of the core and put it into something more structural you'd have a superior board

In general you want to make sure the shape of your heel gets distributed over the largest area possible on the foam beneath... 0-90 and 45/45 plies in combination make for better load distribution while the 45's don't have that much impact on the overall tip to tail board flex

In addition to the higher density core SA mentioned
some other lighter weight solutions are
More plies (both above and below the sandwich) will protect the EPS.
thicker sandwich material makes the sandwich stiffer
Deck pad. (best bang for the buck) distributes the point load of your heel to a larger area of the top deck.

you should be able to get more bang per gram out of the above than you would using wood veneers

Your particular failure "a crack" sounds like a full failure of the sandwhich an extra ply or two on top along with a deck pad can go a long way. but if you're really pounding these things a core with some real compression toughness may be the lightest way to do this.


Some materials notes.

Combinations of cabon, + Kevlar with glass should generally be avoided. especially in a patch . they have much higher stiffness than glass meaning that when the assembly flexes the carbon or Kevlar takes virtually all the load and will fail first while the glass is just along for the ride.

Most people assume Kevlar has high impact toughness.....it doesn't. It will fail in impact (drop testing) before glass. The fibers tend to stay intact however...giving you a nice aramid woven basket to take home your broken surfboard in.

Works great for ballistics as it doesn't penetrate....but still breaks. Might have an advantage in a tumble on the rocks. but when jumped upon Kevlar will behave worse than traditional fiberglass.


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 Post subject: Re: Alternative to breaking surfboards
PostPosted: Tue Sep 03, 2013 7:39 am 
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S.A. wrote:
....and then think that throwing a layer of 0.3mm bamboo into the layup mix will suffice, ...


You've been peeking. :wink:

Thanks for all the replies. I have a fair idea of the design and construction conversation I need to have.


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 Post subject: Re: Alternative to breaking surfboards
PostPosted: Tue Sep 03, 2013 10:13 am 
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This is the one you need, stonger than a windshield.


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