Well, I rode my first board today, and it performed far better than I expected. The good: Very catch free, and the most stable board I've ever ridden when flat footing, very confidence inspiring at speed, excellent carving and extremely light. I couldn't believe how light it was when I first strappe...

Hi webboy, Yes that was what I was suggesting. It would probably work, but I don't know if I'd recommend it, though purely because I haven't tested it myself. I would test it if I were going down the path you are, however for your sake (especially if you're short on $) I would go with the vertical s...

Hey Webboy, Good to see the progress you're making. I haven't read all posts so excuse me if it has already been addressed (in a bit of a rush atm). The arc idea is definitely true, you'll direct a lot of the forces through the sides by cutting it the way you have. This is similar to stone arcs in c...

How'd you go with the floods Tim? Cat skiing at Hotham goes from up the back behind heavenly valley chair, so if you ski straight down you'll generally land around heavenly valley. You can head right across though, we came out behind village chair, if you were keen you could probably get as far over...

The drawing looks good, and the design is not bad either. My concern is that you could crush those ribs fairly easily. It's hard to do an analysis without FEA (and I'm too lazy to draw something), but here's what my instinct tells me. The cordura won't direct the force perfectly down the ribs, it wi...

You may be right about carbon's torsional stiffness being higher than glass, but either way it's so minimal it's essentially irrelevant. You want the fibres of any composite material running in the direction you want to reinforce, which is why 45/-45 or 60/-60 is so common in boards and skis. Glass ...

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

That inertia calc is for I beams. For a square hollow section, you basically calculate the inertia of the outer square and subtract the inertia of the inner square. http://upload.wikimedia.org/math/8/c/5/8c56564f805299eb9e90c8b3e3297434.png So outside is 5x5 = 5*5^3/12 = 52.08in^4 Inside = 5 - 2(3/8...

Desmond - you'd probably be right. True, the pressures are pretty huge and there's a lot of force, but those beams are very heavy. It's highly unlikely that if they did fail, they'd be displaced very far. The hoses will only expand so much. If you ramp up slowly you're unlikely to cause any serious ...

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!

Dunno where my second post went. http://www.gltaa.com/product.htm has the young's modulus for various grades of glulam.

Basically though, with 6 3/4 x 18 glulam beams you should be right if it's fairly thorougly wrapped in cordura. Heavy for a fabric press though.

For a very simple calc you convert the pressure into a uniform load along the beam. Imperial units confuse me so I'll use metric as an example. 350kPa (approx 50PSI) is 350,000N/m^2. Say you have a 2.2m x 0.4m gap (86.5" x 15.5" approx) that gives you a uniform load of 350 x 0.4 = 140kN/m ...

It's doable, sure. If you have a budget of $900 I'd try to aim for cheaper materials somehow though, these costs have a tendency to blow out. Aim for $500 odd worth and you should get it done for $900. I costed mine up before I built it and "everything" came to around $1800. Final cost end...

What's the theory behind the teflon sheet? I'm not sure I follow the reason for it, i.e. how it prevents "edge fall".

Have a look in to a tyre patch and the sealant they use.