Thank you for great advice gestalt.
However I have to disagree with you on Carbon-Kevlar cloth...
The 2 mentioned materials differ so much in their strength, hardness, flexibility, that the fabric combined of those 2 is just a fail imo (you have 1/2 of flexible material and 1/2 of hard material), although the most of main manufacturers use it (read it's cheaper than putting on both).
I have talked to a guy who produces custom wave boards (he doesn't tell as much details as I would need), he said that he uses carbon-kevlar cloth only for the cheap line of boards he produces, otherwise he preffers dyneema (best and most expensive choice in composite for surfboard).
I think I will stick with carbon cloth, top layer glass and reinforcements with kevlar...
concerning easier sanding the glass fiber, I think I will have to avoid the option of having carbon fibre visible on top side of the board... maybe I can get the fabric picture printet on a sticker of board size it would cost about 20$ and put it on top under the lacquer :)
Anyway, I respect your opinion and thank you again for the tips regarding rocker line, I finally read something that makes sense on this issue.
have you weighed the board since you made it, i'm a bit concerned about being able to see if there are any pinholes with the clear lacquer over black,there's one thing about a good paint job, if there are any pinholes they stand out like little craters, i would hate to see you go to all that time and effort to make such a light board and it takes in water, you know water in your board is like trying to get toothpaste back into the tube ,once the waters in there it's there to stay
besides i think it's a good idea to weigh a board after its first outing
no dissagreement with what you are saying re carbon and kevlar. you just need to bear in mind that kevlar is very heavy and isn't adding much tensile strength and is expensive.
so the carbon/kevlar weaves give good strength/weight ratio across the whole board.
building your board out of carbon and only reinforcing the rails etc means that the rest of your board is open to impact damage. although it will be light. building the board out of all carbon and then all kevlar over the top would be heavy and expensive.
i'm not that familiar with dyneema. is your mate bourke?
that said all of my boards are full timber with carbon kevlar reinforcing.
obviously you can buy boards that are all timber, or timber bottoms with carbon decks and other boards are full carbon and a mix of all of the above. there is also the relatively new crows feet weave carbon cloth.
at the end of the day it's all about a compromise somewhere. your layup need to be functional to the desired outcomes.
re your graphics. you should still see the carbon weave through the top layer of glass.
If only the custom board builders would tell all their secrets!
Basically with the layup, I followed how the Nelson factory did it.. Except The board in the video is an invincible waveboard so I left some layers out to save weight..
these were priceless, except dont seal the vac bag like this if your running a fridge pump
the thing that i find very interesting with the skate is how hard the rails are. one thing about the earlier type freestyle boards is people usually complained they were slow. part of this is to do with the chamfer at the tail adding drag and the other is to do with the tuck rail shape npt releasing efficiently.
on the fanatic vid they made a big point about the sailors wanting more speed. they mentioned it several times. i think the very hard rails (that they don't mention) is one of the ways they increased the speed which helps with the double and tripple tricks.
Using kevlar on the specific areas would mean just protecting the crucial parts where the most impacts are possible to occur. I don't need the impact strength in the middle of the board so I was thinking to cut weigth in these non critical areas...
Gestalt -> i'm not that familiar with dyneema. is your mate bourke?
I don't know bourke (I'm from slovenia - europe)
few things about dyneema:
-density 970 kg/m^3 (carbon 1700)
- flexibility in % 3.6 (kevlar 4.6, carbon 1.4)
- impact strength dyneema is 2x more impact resistant than kevlar and 12x more than carbon
-problems... price, no machine processing because it will wreck every tool you normaly use
Hi sideskirt,
you def want to use fabric between the PVC and the poly blank. As well as creating a diaphragm it acts like a blotter to connect the two surfaces through the resin.
Also make up a glue mix (about vaseline consistency) and smear it on the PVC down the centreline of the board, also along the outline about 30mm in from the rail and two stripes down the back in the area between the footstraps. The extra glue is good for preventing delamination.
Lay your fabric out on a bench lined with polythene and wet it out on this surface (I use an old core type interior door, sittiing on trestles for the wetout bench, tape the polythene onto the surface) then squeegy the excess resin back into your container. This gets rid of heaps of excess resin weight.
Heavy boards usually mean too much resin.
Roll the wet fabric onto a cardboard poster tube and roll it out onto the blank off the tube. (no mess method)
To eliminate the deck collapse which Barn mentions I use Tee stringers under the footstrap area. I have a shortened blade (25mm cut depth) in my jigsaw which I use to cut a slot in the blank about 125mm long in the area where the heels are.
I wet out a strip of 200gr cf (prob glass ok also) which is 150mm wide and 125 long.
Wet the strip out , lay it on the slot and poke it into the slot with a steel squeegy.
With the PVC laid on top it is way stronger as the tee section stiffens the PVC considerably when it has cured.
I use the same system along the spine of the board up to the 1400mm point (just at the mast track) which not only holds the rocker line in use but also keeps the board straight while you build it.
You will find that the biggest problem while building is holding the rocker line so don't use too much vac pressure (0.4 bar max , 0.3 even better) Too much vac builds stresses in the poly which let go when you take the vac off and the rocker line goes awol.
You usually loose tuck as you build the board so shape in plenty.
Good luck with your project, very satisfying sailing your own stuff.
I was actualy thinking of reinforcing the part beneath footpads with carbon or kevlar directly on the EPS (2 layers), then glass layer all over the blank, on this I would put Airex foam, then 1 layer of carbon and 1 layer of glass + reinforcements.
Thanks for the tips I will lert you know about results in a few months, for now it's just collecting knowledge and saving money for start :)
the other reason why you want glass around the blank is to waterproof the core.
as well as extra kevlar and carbon around the feet area to strengthen it. you can also use heel bumpers. gives the board a smoother ride and works very well.
Actually, the Airex foam prevents water reaching the core, because it is a type of sandwich material that cannot be damaged by impact so even if I destroy the layers on top of it, it won't let water reach the core...
I will glass the blank for other mentioned reasons for sure, you convinced me :)
BTW here is the link, of what the shaper I talked to makes :)
^ yeah, that's all well and good until you cut in the boxes and plugs.
before i was referring to the witchcraft boards when i mentioned bourke
If you mean about the foam, it is bonded with epoxy as well as the glass and carbon parts, so it's completely sealed.
Oh one more thing has been bothering my mind lately and I forgot to ask...
how to vacuum the board... can I put 1 layer of cloth, put epoxy on and then turn the board upside down and laminate the other side and so on before vacuming or I have to make 1 side then when it dries turn it around and do the other side?
I see your point here...I was thinking more ore less the same thing.
I will put my CAD 2d design soon for you guys to see and whether you will have any suggestions for improvements.
