Carbon Fibre Rails Method

hewitt91 · April 7, 2011, 11:33am

just finished 2nd attempt at carbon fibre rails!!. thought i would share my process for ideas, education or just curiousity.
This was for a 6’ x 19 2/5 x 2 1/2
After reading some new articles and what ive learnt from my last attempt should hopefully get a better finish (i ran into some trouble with last board, wrong resin ratio duuhhhh)

The blank baby ( real excited with this shape, largely based upon the margo nugget by dhd)

I started by just masking off the rails. the tape is 6.5cm wide so i made a 65mm strip and marked where the tape would lay.
from here i drew in some approx line and taped with glad/cling wrap. now just paint dem rails black!
this was an idea ive heard because sometimes you can see white dots inbewteen the weave. i didnt a basic job just to darken them a bit

Now the layed cloth, i rested a weight on cloth at nose and ran it round the rails trying to keep about 1mm lower than my tape line, some ideas ive heard are to use adhesive spray to hold in place?
i tried this a bit but found it kinda holds itself in place, also since i have a rounded tail i just used one big peice nice

Now ive gonr the perimeter of the board i rest my weight on both ends at the nose and cut.
making sure that the cloth isnt sagging or too tight, it may try and sag a bit.

the tail is a tigh angle so ive cut 3 relief cuts to allow for it, ill do this on other side when i flip the board.

excitement builds! saturating the cloth, i used a normal shitty brush to wet the tape as it saturates it sticks to the board, i mixed up about 250ml of resin but probably could of gotten away with less than half that.
i used generously and had heaps left over. carbon cloth is harder to wet than fiberglass, glass just absorbs it the carbon you kinda need to work into it.
once i was happy with the top i flipped the board, the wet suction kept it in place. wrape the bottom the same way

Now also a fun part, the rails probs have a little too much resin in them and need to be pinned to the board.
i haerd all this talk about cling wrap… wtf is cling wrap! i googled it to realize its glad, plastic wrap by aussie terms…maybe i just need to get out more
i had my most-of-the-time useless brother help me here. pull out a length and carefuly place it against the rail.

nice and shiny yes, the good thing about this is the finished surface with be a replica of this surface so just pul out all the wrinkles and your good.

my little adition to this stage was spray the wrap with rp7 the creates a frictionless surface you can put the rail inbetween your thumb and finger webbing and push out resin towards the ends
this can be a trickier part but im comfident it will get better results. after doing my best to get right i left it to cure, now pray

returning about 1.5-2h later i ran a knife down my tape line and peeled away the wrap and tape.
i am now left with my rails with a precision layer of cling wrap, you cant even notice it.
parts of mine popped up, generally around tail and nose, tail was the trickiest. but i just used masking tape around the rails to hold these bits down.
remember about our little layer of clingwrap keeping us safe. you can see my extened black line but i dont really mind, ill fix it later im sure
i waited 12 more hours

After some light sanding knocking off those wrinkles i missed and tail was a little bloated with resin.

i was stoked with the mid rails they came out as close to a can see perfect. not even gonna touch them with the sandy
i have a few bits where cloth is kinda floating/ not attached but was prepared to have a few, ill either try and touch them up or cut them out
not sure yet oppinions welcome.

now as always my delay as i figure the artwork out grr need to give this stick a hack! such antisipation to see how it rides

oh if anyone was curious like me to see its wieght its about 1.05-1.1kg and this is the stage a shaped ply stringer would be weighed
so is that heavier or lighter for a 6’x19 2/5x2 1/2??
it kinda feels about the same.

hopes this helps anyone looking to do a carbon railed board, was worried about stiffness but does seemed to flex quite easily.
Cheers Guys!!!
Tom

everysurfer · April 7, 2011, 3:32pm

Did you use resin or epoxy? Do you think a light sanding at the smooth parts might make the next layer grib better? At this point, with only the rails done, does it flex more or less than a stringered blank? Does it flex differently in different areas? Midpoint where the carbon is vertical, is it stiffer than where the carbon lays flatter on the nose and tail?

johnmellor · April 7, 2011, 6:19pm

"my little adition to this stage was spray the wrap with rp7 the creates a frictionless surface"

I'm afraid I don't know what rp7 is? Coarse sanding any areas that will be glassed over would be a good idea.

I would avoid anything that might create bonding issues with subsequent layers.

hewitt91 · April 7, 2011, 9:24pm

ah yes true guys ill probs do it with a higher grit such as 320 or so. opposed to 80.
rp7 is a lubricant like wd40 anything would work really

to everysurfer after giving it a work out it does flex more in the middle than a wood stringer, the way i figure it it ive used 65mm of tape the hold perimeter
a stringer board would have thickest ply in middle and thin towards nose giving flexible nose and tail.
which hosts more beneifits?

johnmellor · April 7, 2011, 10:00pm

"rp7 is a lubricant like wd40 anything would work really"

If I understand correctly you sprayed the lubricant on the outside of the Glad Wrap so your hand could squish the resin under the wrap?

Several people have had mysterious bonding issues with epoxy. Hopefully you will not have any trouble like that.

It is generally recommended that you don't spray stuff like silicone or other lubricants anywhere near an epoxy glass job.

everysurfer · April 7, 2011, 10:37pm

Just wondering, it seems that the current trend is to direct the greatest flex to the tail. Wonder if a second band it the middle only where you might want to keep the stiffness.

Did you consider the flex when designing the rocker?

red_boards · April 7, 2011, 11:15pm

You have thinner half-pipe of carbon rails at nose and tail and
different overall thickness through the centre (plus a domed deck?) so
you’ve already got variable flex at nose and tail.

I read an old adjustable rocker table thread yesterday where there’s a lot of talk about how BillBarnfield did his boards back in '05. One thing of interest was the idea of keeping the (wooden) rails, top and bottom surfaces largely separate by not using laps, but just a single layer of cloth to join the cladding on each of the surfaces. This lets the rails act as springs without being stiffened by being connected too much to the deck and bottom. May be worth thinking about.

hewitt91 · April 8, 2011, 4:34am

Yeah i had foam and rails quite well protected when i used this spray though maybe it isnt the best solutioin… perhaps a more friendly lubricant?
and if i sand up the rails hopefully should have a good bond,
problems with epoxy? i havnt had any trouble like that, last time i just lapped over the carbon… seemed pretty good maybe a bit stiff, it was a big board though
i didnt take any consideration into flex with the rocker, i based this board apon a ply stringer model so was really just trying something a bit different :s didnt go into great thinking about ammount of flex etc
for future i suppose flex and rocker will increase when pushed into corners? so would you take a little out of rocker in shaping?
tho i like the idea of how avoid so much lapping can compliment the flex of the carbon, if i wanted to alter the flex positions perhaps i could adjust how much lapp i get through the board
e.g full lap on nose then none towards tail?
is this a possible option?

lemat · April 8, 2011, 8:05am

In my experince carbon rails blanks are flexible in the midlle than wood stringer blanks, they flex more like PVC stringer blanks but depend how far is carbon from neutral fiber and type of carbon fiber. For me interest of eps/epoxy is to use more fiber to cover a light “shitty” foam so it’s a stronger durable skin. If you do this with a central wood stringer you may have to much stiffness.

Normaly a sandwich structure use a structural foam wich connect thin skins. Because PU or EPS foam used for surfboards blanks are far from structural foam you need to use a stringer to stiffen structure or thicker skins, this second way is better for durability that’s way sandwich skins are generalized for HP composits sandwich structure .

For me well made carbon rails give just a bit more of spring than same weight stringerless, and more dynamic durability because of superiority of carbon for dynamic load duarability. But an optimize galss/epoxy composit can give even better results.

Sorry for my frenglish