Bali, Indonesia, welcomes Shinai:)

Weather in Perth wasn't so good to test my board. So made an escape to Bali. And what a board this is!
Notice, I even made all fins of chopping board! Yes, kitchen board we all use...Took me two hours to make it.
And finally, today I've ridden it. Review soon...

Shinai is born - Shinai je rođen

On left is Shinai, my new kite board!  On right my 2011 build (no name:)

By suggestion from kiting community, and being a bamboo board, hence Shinai ((竹刀) - is a weapon used for practice and competition representing a Japanese sword.

Weight before accessories 2545 grams, 137x40.5cm, concave 3mm, rocker about 3cm (straight 1/3).

And now for my next project, I'll make some fins for my board...

Kite board rails and varnish - Rub daske za kajtanje i lak

As I've left some bamboo ply all around kite board rails, now is a time to cut it and make rails. Huh, that was a tough job!
Since my board was glassed on both sides, it's very hard to cut fiberglass, even harder with a hand saw! Decided to finally buy a jig saw, but even with that was not easy to cut.
The problem is, glass is an insulator and the metal blades tend to overheat quickly and than metal just melts. Spent a few good blades for this...
Anyway, finally the board is cut. Now I need to sand out bamboo excess and finally got myself another machine to work with, a belt sander. Made this setup which worked perfectly:

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Kako sam ostavio nesto bambusa oko rubova daske, sada je vrijeme da dasku ispilim na mjeru i napravim rubove. No to nije bio lak posao!
Kako je f. staklo na obje strane, vrlo ga je tesko rezati, jos i teze sa rucnom pilom!
Konacno se odlucih kupiti ubodnu pilu, no ni s time nije bilo nista lakse.
Problem je sto je f. staklo izolator i metalni noz ubodne pile se brzo ugrije i nakon toga rastopi.
Potrosio sam cak nekoliko dobrih nozeva za ovo...
Konacno, daska je izrezana. Sada trebam pobrusiti rubove od viska bambusa i za to sam si kupio novu masinu, brusilica sa remenom. Napravih ovo i radi izvrsno:

One hour or so and was finished. Must remember to have a decent breathing mask, this is a fiberglass I'm sanding and it will be a nasty thing to breath!

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Nakon jednog sata bilo je gotovo. Zapamtimo koristiti dobru masku za disanje, jer brusiti fiberglass i udisati ga je nezgodna stvar!

Finally, it's coming to an end!
Now I just need to varnish the board and how long it takes to make a board, it might take even longer to varnish it!
However, this time I'll be doing both sides in one single run. And the above photo is showing how. I've placed 4 small clamps and will rest my board on it while varnishing the other side.
And, important thing, there is enough space to place a 100W light bulb under the board to generate some heat.
Than, I've placed a styrofoam on sides and top, covered with towels and left over night... Process repeated 5 times. That is 5! Would like a super shine board!

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Napokon, doslo je do kraja!
Vrijeme za lakiranje je skoro isto koliko treba da se napravi daska!
No ovaj puta lakirati cu obje strane od jednom. Na gornjoj slici se vidi kako. Stavih 4 male stege na koje cu okrenuti dasku i lakirati drugu stranu.
Zatim, staviti cu jednu zarulju od 100W ispod daske tako da ju grije. Mjesta ima dovoljno.
Nakon toga, sa malo stiropora daska ce biti kao u kutiji da se lak brze osusi preko noci...I citav proces ponoviti cu 5 puta, dakle 5 farbanja!

"Mega" kite board rocker - "Mega" od zakrivljenosti kite daske

After I got my kite board of the vac table, was quite surprised to find just a tiny board rocker. The bamboo spring back is much more than 30%, and wasn't expected this.

So what to do now? I could glue a second bamboo layer on top of it to get a decent rocker. But, it won't be a light weight board any more.

So, made an experiment and used a carbon - kevlar fiber fabric on top of bamboo strip to see how that will work.
And, I got some rocker.

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Nakon sto sam skinuo dasku sa vakumskog stola, iznenadilo me da je zakrivljenost (rocker) daske skoro nestala. Naime, kod bambusa je ocito povrat elasticnosti znatno vise od 30%, sto nisam ocekivao.

Dakle, sto sada napraviti? Mogao bih zalijepiti jos jedan sloj bambusa da dobijem pristojnu zakrivljenost. No tada daska nece vise biti lagana, vec znatno teza.

Onda sam za probu zalijepio carbon kevlar fiber platno na gornju stranu bambusa da vidim kako to radi.
I, dobih zakrivljenost.

 
To cut a kevlar fiber fabric is a real pain. You'll ruin a decent scissors in a second and fiber will be everywhere. And because I like to complicate things I want my carbon kevlar fiber on top on my board but not from rail to rail.
Than, I was thinking why not to semi cure some epoxy and than cut it? Immediately after, vacuum bag it.

Worked as a charm!

1) First I need a template for applying epoxy on carbon kevlar fabric.
2) Than applying just enough epoxy around a template.
3) One hour after I cut kevlar  with an extremely sharp knife around a template.
4) Done. Carbon kevlar fabric is now ready for my "mega" rocker vacuum jig - 10 cm! Used 50g 5:1 epoxy.

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Rezati carbon kevlar fiber platno nije lako. Cak i pristojne skare ce biti neupotrebljive nakon par sekundi rezanja i tkanina ce se razici po svuda. I naravno, zato sto ja volim komplicirati stvari, zelim da moje platno bude na gornjoj povrsini daske ali ne od ruba do ruba.
Onda sam dosao na ideju zasto ne bih upotrijebio epoksi i nakon nekog vremena probao rezati platno? I odmah nakon toga na vakum stol.

Radi odlicno!

1) Prvo mi treba sablona da nanesem epoksi na carbon kevlar platno.
2) Nakon toga nanesem malo epoxija oko sablone.
3) Nakoj jednog sata sa vrlo ostrim nozem izrezem platno oko sablone.
4) Gotovo. Carbon platno je sada spremno za moj vakumski stol i "mega" zakrivljenost- 10cm! Koristio 50 grama 5:1 epoksi.


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And 10cm jig for the rocker is because I'm still expecting 50% and more spring back! And that might make just about a decent rocker of 4cm:) Will see tomorrow! Can't wait...

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Zakrivljenost od 10cm je radi toga sto ocekujem 50% povrat uslijed elasticnosti! Sto ce mozda ostvariti pristojnih 4cm rockera! Vidjeti cu sutra, jedva cekam...