Finished kite board

Finally second fiberglass layer goes on top! I've decided to finish glassing with the proper breather and bleader fabric and what a difference!
This fabric is really cheap, just a few bucks for couple of meters. Now, vacuum bag is a different matter! Since I'm using a tick vinyl for my vacuum bag, it is possible that the fabric won't bridge the gap between two layers, marine ply and bamboo. But than, the proper thin vacuum bag fabric is so difficult to work with that I've put everything in my vinyl bag. This means the proper vacuum fabric bag inserted in my bag and applied vacuum.
The reason for this is that I just couldn't apply the vacuum on a new 'proper' bag:(
And since the time is important while doing it the only option was to quickly use my proven solution for vac bagging.

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Konacno stavljen zadnji sloj fibergalsa na gornju povrsinu daske! Odlucio sam zavrsiti taj proces sa profesionalnom 'breather' i 'bleader' tkaninom i to zaista vrijedi!

Tkanina je jeftina, nekoliko dolara za par metara. No, vreca za vakum je druga prica. Kako sam koristio dosta debeli vinil kao materijal za vrecu, vinil se vjerovatno ne bi dovoljno savinuo izmedju dva slojeva sperploce sto cine dasku. No, vrlo tanak materijal za 'pravu' vakumsku vrecu se pokazao kao tazak za raditi, pa sam na kraju sve zajedno stavio u 'moju' vinil vrecu. Sto znaci 'prava' vreca u vinil vrecu i tad pod vakumski pritisak. Razlog tome je sto jednostavno nisam mogao dobiti vakum na novoj 'pravoj' vreci od vrlo tankog ali cvrstog materijala.

I kako je vrijeme jako vazno dok se to sve radi , zadnja je opcija bila da brzo vakumiram sa dokazanim postupkom.

I'm using a special super clear epoxy as final fiberglass resin. Around 52 grams.

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Koristim poseban bezbojni epoxy kao zavrsni sloj uz fiberglass. Utroseno oko 52 grama.

Proven vacuum quick release  clamp:) A bit of Blu Tack around. Need to make this better for next time. Also notice VERY important thing which is a perspex leftover with a small hole in the middle and channels like X under. Without this the 60 cents vacuum plug can't stick on vinyl vacuum bag!
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Dokazan nacin spajanja vakumske pumpe. No, moram sistem jos doraditi. Primjetite znacajnu stvar sto je komad pleksiglasa sa malom rupom u sredini i kanalom kao slovo X ispod. Bez toga par kuna vrijedan vakumski priljepak se ne moze priljepiti za vakumsku vrecu!

Vinyl vacuum bag sealed this time with Blu Tac. Quite faster than using a tape. And reusable too!
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Kompletna vakumska vreca zatvorena je 'plastelinom' tj. slicnim materijalom. Puno brze za raditi nego selotejpom i mogu ponovno koristiti!

Too much of epoxy resin going out through perforated breather fabric. This is exactly what we want! Note, applied vacuum of around only 15 mm of mercury. You can see the vac pump under the bag and a white breather fabric...
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 Visak epoxya izlazi van kroz perforiranu foliju i to je upravo sto zelimo! Ovaj puta koristio sam 'samo' pritisak od 15 mm zivine vage. BIjela tkanina je 'breather' - za disanje.

Vacuum applied. Didn't have a time to remove my plaster mold from it...Roller used for pushing epoxy into the fiberglass.

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Vakumska vreca. Nisam imao vremena ni da izvadim gipsani otisak iz vrece...Valjak je koristen da se epoxi dobro upije u fiberglass.

 

Final kite board after black paint and varnish on top and bottom. Mirror shine!

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Zavrsena daska nakon farbanja crnom bojom i zavrsnog zastitnog sloja vodootpornog laka. Sjaj kao zrcalo!

Board in action on river mouth ( 25 Dec 2011, Denmark, Australia )

Board details: 

• 135.5/41.5 cm
• Rocker 4.2 cm
• Concave 5 mm 2/3 of length, tips no concave
• Weight 2.8 kg no accessories
• Bamboo top 6 mm
• Marine ply bottom 6 mm
• Flex comparable to Xride 2009 133/39cm

Gipsani otisak - Plaster mold

Dugo vremena sam razmisljao kako dobiti potrebnu zakrivljenost daske za kite boarding/surfing iliti kajtanje. Ima nekoliko "skola ucenja" izrade zakrivljenosti daske.
Naprimjer, jedan od nacina za dobiti zakrivljenost je izrada tzv. "stola" od deblje ili tanje sperploce koju unaprijed zakrivimo stegama. Ili masivnim sarafima. Na taj stol polazemo novu dasku.
Drugi je nacin izrada zakrivljenosti od drvenih letvi koje ispilimo u odgovarajuci oblik, poredamo jednu do druge i time dobijemo potrebnu sablonu. Takodjer na tu sablonu stavljamo novu dasku.
Itd.
Za vecinu slicnih stvari postoje programi na Netu koji vam mogu pomoci kod izrade.

Zatim ljepimo slojeve daske jedan na drugi na ovakvom "stolu" ili sabloni. Kad se ljepilo stegne, daska ostaje u obliku stola.
Ja sam odlucio pokusati najbrzi i najjednostavniji nacin za izradu zakrivljenosti. Jednostavno sam stavio par letvi, pleksiglas ispod i deblji najlon preko svega te nasuo dovoljno gipsa da mogu "otisnuti" svoju komercijalnu dasku. 5kg gipsa je skoro pa dovoljno. 7 kg bi bilo taman.
Time cu dobiti potrebnu zakrivljenost! Sve gotovo u 30 minuta. Primjetite fibreglass pojacanja na najlonu. Ista pojacanja su na doljnjem dijelu daske prije nego sto ju stavim na gips.

Nakon toga obradim rubove gipsanog otiska, stavim slojeve sperploce koje lijepim, vakumiram kompletno sve i nadam se najboljem!

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For a quite some time I was thinking how get a rocker and concave for my kite board. There are a few "schools of thoughts" how to do this.
For example, a lot can be done by making a "jig table" of thin or thicker ply wood. With or without a massive bolts/nuts. Than we put a new board on a jig table.
The other way for doing it might be to cut a number of wood pieces with a router or similar and than placing all this pieces together into one shape. The new board goes on top of it as well.
Etc.
For all of this there are a number of different software on the Net.

I've decided to go with a fastest and much easier "jig". Simply placed  some perspex under the PCV foil, put some wood leftovers around and poured 5kg of casting plaster on top. Than, my commercial board goes on top to get the exact shape. 7kg of plaster would be better to work with.
All together, 30 minutes of work. Note, a fiberglass reinforcements on the foil. Same applied at the bottom of my board before placing at the mold.

Latter on, a board goes out, final touches around the edges of my plaster mold, the ply wood goes on it, vacuum applied on everything and hoping for the best!

...