Yesterday we received the Clearwater 2600 aluminium kit, and now we want to start “glassing” the front wing.
The instructions say to use 3 to 4 layers of 4 oz glass on the EPS foam wing.
However. We want to use carbon instead of glass.
Anyone here who might know how many layers of carbon are needed to have at least the same strength as 4 layers of glass?
The carbon we have here is 200 gr/m2 keper.
I bet you could message the clearwater guy, I saw on his Instagram he had laid up foils before in carbon.
Yes. We did try to contact him, but till now no reply.
I guess that he must be very busy.
So I was hoping someone here could help.
Anyway. For now we are going to use 2 layers of 200 gr carbon. We can add more if needed.
If weight isn’t too much of a concern I’d do three layers to be safe. You want a wing that large to be strong enough to resist some impacts when carrying it and hitting stuff. Perhaps two layers of carbon with a layer of glass on top would make it a bit tougher! Are you vaccuming it?
Thank you.
We were thinking 2 layers of carbon too but no glass on top.
We do also have vacuum available, but are afraid that the wing might twist / bend out of shape because of this.
Decisions… Decisions… We only have one change on this…
The effect of an optimised layup is not huge in weight or performance if you’re not skilled. Because of this i’d stick to clearwaters original layup and weights and not change to carbon but this doesn’t help you 
So:
Don’t worry, you can sand your defects but need to take care that the vacuum bag is free to compress around the core without distortion. Allow the bag to suck in slowly, watch it closely and release vacuum to reposition bag if needed.
Preparation is everything when using vacuum! Cut everything. Set up all tools. Try the vacuum bag before. Watch some videos. Do a trial with a core dummy. chances of destroying the plug are small if you prepare yourself.
In composites the strength comes from the fibers but the strength of glass and carbon fibre is not wildly different.
Stiffness on the other hand is a lot higher for carbon but this is mostly important for hollow profiles where buckling is the failure mode or where little to no deflection can be allowed. How much this affects you is connected to how stiff the EPS core is.
i’d not worry so much about the exact fibre weight, i’d use equivalent weight of carbon or slightly less, use vacuum to get rid of excessive resin and shed some weight there. The resin does not contribute to strength or stiffness in comparison to the fibre.
Fibre direction is critical, most of the fibers should go in width direction of the wing. If the eps core is stiff then i’d go 2/3 or more unidirectional fibre in width direction with some 50/50 reinforcements around the mast connection.
Thank you for the info.
Please note that the wing is not from wood, but from EPS.
Yesterday my dad and I put the 1st layer of glass on our new board blank, and used a vacuum bag.
Unfortunately this did not go well. The vacuum warped / bend the 13 cm thick EPS blank so badly, and after seeing this we stopped the vacuum process, and let the epoxy set the old way.
Lessen learned. Next time we need to vacuum bag with some pre shaped support inside the bag.
After this ordeal we are not so sure anymore about vacuum bagging the eps wing as making a support for it will be difficult.
So… Carbon. 2 layers. extra carbon near the support. Wet.
Then you probably did not have large enough bag or too stiff bag material. You need to pre crease the bag where there’s high curvature or corners.
If the eps is soft enough to compress under full vacuum then use lower vacuum or do one layer without vacuum first and let it cure.
The bag we used is one they use for king-size mattress. Really big and rigid plastic.
To much vacuum could be the problem!
We are using a venturi vacuum valve connected to our big compressor. When used the compressor is blowing just under 10 bar. We do not know how much vacuum this is generating, but the bag is so tight against the board that it is impossible to pull it away.
Not makin pre creases might have also caused the problem!
The problem (warping/bending) was at the end of the board. Right at the place we made room for the jetbox motor area.
We are going to try again, but this time without any glass/epoxy to see if the board shape will stay okay.
Thank you for the tips
I use soft/thin plastic foil for general surface protection during building. It has to be flexible to stretch and shape rather than deform your part but this still has to be combined with pre-shaping and pre-folding for the bag to follow part contours well.
Butyl rubber is normally used for the sealing of vacuum bags but this is really expensive. I find that hot melt glue works equally well for sealing the foil and it costs nothing 
Regarding the bagging of the board, the king size vacuum bag looks pretty expensive.
Check out this bagging material. It’s sealed to make a tube, so you just have to seal the ends.
If you don’t want to use Butyl tape, grab some aluminum u channel and use a power cord (or something that fits into the alu channel) to make the seal on both ends. In theory it’s reusable, but once you start cutting holes in it / using it multiple times, it becomes increasingly difficult to pull a vacuum. This is $6.30 / yard for 60" wide. I’ve not tried the hot glue trick, but melting the ends is certainly an option. The downside is that it becomes less & less re-usable, as it becomes shorter & shorter, which is the same as with Butyl tape (at least on one side). I’m using butyl tape on one side and alu channel on the other with these big bags and can get 3 to 4 uses if I’m extremely careful.
More layers of carbon the better, especially if you are going to be sanding. It’s easy to break through a couple layers of carbon while trying to make a perfect finish in carbon fiber. A layer of glass sounds good in theory, but also quite easy to break through while sanding. All of these reasons are why I moved to making molds, so I get a perfect finish every time, as it comes out of the mold… Obviously it is a lot of work to make a plug, mold, then a part for a one-off.
The vacuum bag we are using now was something we had here. It was not used anymore.
That tube film does look nice, and if we need to replace the king size vacuum bag we will use the film.
The seal on the vacuum bag works great, and your alu channel seal trick looks nice.
What we have done before (with another small bag), was by using a PVC pipe with a “wide” cut all the way along. Put the end of the bag in this cut, and put another PVC pipe in it (looks like a U with a o inside it) It works perfect too.
Today we had a look at the board with the 1st layer of glass on the bottom. It still looks usable however all of the 1st layer of glass (again only on the bottom) peeled off really easily! (delaminated?)
It did not even damage the EPS.
The glass we pulled of is nice and stiff. (No EPS on it)
It almost looks like the EPS did not saturate with epoxy… However feeling with the hand it does feel like something is in there.
So now have a blank with nothing on it.
Do you maybe know what we did wrong?
We did 1st put some epoxy on the bottom of the blank, and after that we put the glass on it, and used more epoxy!
After this we put it in the vacuum bag for about 1 hr. Than due to the warping / bending we took it out the bag again and let it cure the normal way!
You should always lay the glass/carbon cloth on dry foam first then apply resin on top and move it around so it soaks all the way through. The technique you did is more prone to leave air bubbles especially if you laminate several layers of thick cloth at the same time. You should watch some surfboard glassing videos, you’ll see what I’m talking about.
My hypothesis about why the glass didn’t stick to the foam very well are:
I personally lay all carbon fiber and fiberglass by hand on my board. I even laminated a thin carbon fiber lid with Carbon fiber wrapping around the edge without a vaccum. It is definitely more work because you have to use a spatula and push the CF against the foam in sharp angle areas until the epoxy kicks and starts sticking to the foam. However, you don’t get any wrinkles using this technique and you can mold the CF cloth however you want if you are patient enough. I was able to mold 3 layers of 6k 6ox 4HS Carbon Fiber cloth around a 90 corner that was barely rounded. You might have a slightly heavier lamination with this technique but if you use the right amount of epoxy, I think the difference will be minimal and you’ll have a much cleaner result with no sanding required.
Sounds like delimitation without a good bond. Rough up the EPS with some 120 grit to make sure the surface will bond to the glass.
What epoxy are you using? What’s the type of fiberglass?
Both @Vicdes2 and @noahark are correct.
We did sand the foam with a high grid. We have now used a rougher grid and all is in the vacuum bag.
@Larsb was correct about the “not having creases”. We pre creased the bag on the trouble parts, and this stopped the board bending / warping.
@Vicdes2 As mentioned before. We had to remove the pressure before it cured as it was causing warping / bending problems.
Also. Your 3rd point can be true too. We did not only add epoxy / glass, but also cork on top of that.
It looks like the cork absorbed most of the resin.
We have watched many videos on how it’s done, and they make it look so easy.
Anyway. The board is in the bag again. Only doing 1 layer this time.
Fingers crossed 
Did you use vacuum cleaner to remove all dust from the blank before applying Glas and epoxy
We used the compressor to blow away the dust. For sure the blank was clean.