Carbon Fiber Rookie

[Brian10s]

Ok Guys lets hear soem expert opinions.

I am going to begin a rebuild project to replace the cockpit sides on my Roper. I want to put carbon fiber on the sides as a safety inprovement. I have never messed with Carbon, so am looking for some help. ( I have asked a couple of buddies and they have been very helpful but thought this might make a good group project and would get this type of safety info to everyone).

I did an online search for carbon fiber and found a ton of places to get it.

1st - What type is generally the best for this application? One catalog shows the following: 1kx1k, 3kx3k, 3kx1k, 6kx6k, 12kx12k all in 100% carbon fabric. It also shows Carbon & Kevlar hybrid and a Carbon & glass fabric. What type/ thickness should I use for cockpit sides?
Put it on both the inside and outside?

2nd - Ballpark pricing and/ or does any racer carry it for sale. (ie is there anyone out there buying in bulk?)

Thanks,
Brian 10s

[modhydro]

Thoughts on composites

Brian,

I don't like carbon on cockpit sides. It is incredibly strong and stiff, but in my opinion too stiff. I prefer Kevlar on the inboard side of the cockpit. It has great tensile strength and is also very resilient. I've simply seen too many cracked or shattered carbon parts. Even on race cars, most of the impact strenght comes from Kevlar, not carbon. I've never had one of my Kevlar faced sides break yet and I've seen Jimmy Robb throw some pretty rough hip-checks at his. I figure if it can withstand that, it will take pretty much anything. I just prefer the mix of strength and flexibilty over extreme stiffness. One thing to bear in mind is that Kevlar sands just a little worse that mud. I wind up laminating it on by precoating and sanding the side with it flat on horses. I roll out the Kevlar and wet it out from the top with a squeegee. When the epoxy is 90% cured you can cut the edges with a sharp razor and have a neatly finished edge. Drop me an e-mail if this didn't answer your question enough. For materials RAKA from florida usually has good prices on fabrics whatever type you choose.

Steve Roskowski
steve@arcindy.com

[Sonny]

Composite materials

Maybe if you called some of you'r local vocational school's and colleges someone offers a night cource on composite materials. I know when I looked for the same info I found a boat builders expo they hold once a year, I think it's in Texas. But I know all the info you could ever want is there. I also found out the best way to buy carbon fiber, or rather to survive buying it is in surplus auctions. good luck.

[DeanFHobart]

Composite Books...

Go to tap plastics.com and find some books on composites etc.

Good Luck.

Dean Hobart

[hydroplay]

As with any engineering project, the first thing that should be done is to identify the problem. You say you want to do it for "safety improvement". While that may seem straight forward enough for you, it really doesn't identify anything. Are you trying to make the cockpit side stiffer so it won't break or flex from the driver banging against it in turns? Or are you trying to make it more impervious to boats hitting it from the outside?

Both of those cases have stresses placed on the cockpit side on opposite faces and in opposite directions. An optimum solution for one problem may not be optimal for the other, particularly if you are dealing with thichness constraints on an existing hull. All of these reinforcing fibers are strong in tension and weak in compression- the opposite of wood.

Don't let Steve scare you away from carbon/graphite. I'm sure he has seen many broken carbon parts from racecars and few of kevlar. Go look at contemporary car parts and you'll see there just aren't many kevlar parts used so of course there are going to be more broken carbon parts. But the failure mode between carbon and aramid is different. The carbon will typically break with sharp edges and jagged fragments. The aramid tends to just fail in the fiber-to-epoxy bond so the fiber is more or less intact and the epoxy just crumbles out. You sometimes think that you could shake the remaining fabric to remove the epoxy and you could use the fabric again. But carbon is far easier to cut and work with for amateur use, requiring no trick sissors to just cut the kevlar to begin with or sanding worries when laminated.

Whatever you use, play around with small pieces and scraps to gain experience before laminating entire cockpit sides. Here's a pic of a current AXS/A hydro project for Bill Hemp with carbon fiber laminated on three of the 4 cockpit sides in both 5.7 and 10 oz weights.

[csh12M]

Looks nice Sam! Where do you get your 10 oz, I can find the 5 oz everywhere but can not find the 10 oz in many places?

Looks like Bill wants higher cockpit sides? I have driven all three of Miskeriks B&H and think they drive and turn great, but have wished the sides were a bit higher.

Happy Holidays
Dean

[STEVE FRENCH]

Brian,

Matt made carbon sides for Palmer's FEH. I believe it is a Scott Reed hull with Matt's Arltralite sides incorperated. May want to contact any of them. Seems you could make a cardboard pattern of what you want and have Matt build them.

19P

[hydroplay]

Dean,

Most all of our cockpit sides are made from 16 to 16 1/2 inch wide panels for efficient use of material, ie 3 sides from 48 inch or 1250mm wide plywood. Higher is certainly an option at additional cost. Optimally, I would rather see a driver get lower in the boat than build a higher side to hold him in. A higher side will increase the leverage the driver has to shear it off at the deckline. This means a higher side must be stiffer to not break at the deckline. So it is heavier because it is higher and has to be heavier yet to be stiff enough to not break because of the increased leverage. No free lunch here! Miskerik is a thin, nimble, young driver and can get low enough to stay in easily or at least he hasn't complained otherwise. A driver should brace against the outer cockpit side down low with his leg and thigh, not up at the top with his ass,
and hang on with his throttle hand and forearm.

Carbon fiber fabrics are available from numerous sources. My current 10.9 ounce stuff came from Aircraft Spruce

[jsilvestri]

Sam,
Once, the carbon is laminated to the cockpit sides, does it cut easily and cleanly with ordinary woodworking tools? The reason I ask, is that I will be making cockpit sides laminated with carbon on each side but would like to laminate everything together then cut my lift into the sides. Thanks.

Steve, do you know what Matt charges for two premade cockpit sides? Thanks.

[csh12M]

That makes a lot of sense Sam.....I have tried to learn to brace lower, but it seems like my hips are more the factor than my legs. I need 20" to keep me in and braced the way I like, but I am also 6'2". You are right about the high sides being weaker at the shear line, that is why I need to find 10 oz. Glad to hear Aircraft has it that is usually where I get my stuff but they were out of 10oz the last few times I called.

So I see Bill is still going to be competeing in AXS.....when does he get a 20SSH or OSY400 ride?

Donny Allen Jr. wooped me at Big Rapids........got the inside both heats! When are the young guns going to be ready for Yamatos?

Later,
12M

[STEVE FRENCH]

Joe,
No idea, but seems it would save alot of TIME till you get more practice at working with the material.
Maybe if if he had several orders to production line you guys could save......

I think the sides of my Artlralight are laminated over ridgid foam. I heard Ian Augustine came out of this boat very hard and the sides held up to his wieght. Any comment on that Ian?

Give Matt a yell

Tell Dante' I have a couple .015 pistons/rings for that 20H cyl I sold him. Will call for address soon.

MERRY CHRISTMAS ALL!!!!!!!!!!!!!!!!!!!!!

19P GOING FASTTTTTTTTTTTTTTT!!!!!!!!!!!!!!!!-----to visit friends and family.

[hydroplay]

Joe,

Carbon fiber laminated with epoxy cuts, files and sands easily with woodworking tools. You can saw it with a saber saw just like it was wood or rout it out with a router if you have a template. I like using the router/template more because pencil marks are difficult to see in the black surface and because carbide router bits hold up much better against the CF. The laminate is very abrasive to ordinary steel saw blades but they do cut fine until they get dull. Here is where kevlar is really miserable stuff to work with as it is impossible to cut nicely and have neat finished edges. Carbon cuts well and can be sanded so the exposed edges can be smoothed and radiused.

The dust from carbon fiber is very itchy. If you think fiberglass dust is bad, CF dust is worse. In this respect, sawing is better than routing because there is less dust. I precut the sides before laminating the CF to either exact dimensions and then trim the partially cured CF overhang or cut the sides fairly close so there is minimal CF dust generated.

In any case, laminating CF to plywood or some other core material is certainly mot all that difficult if you do it flat so gravity is on your side. If you're capable of building your own boat, you should be able to do this.

[hydroplay]

Dean,

Bill's OSY boat is already finished, painted and rigged, even has a letter instead of just a number. Its a pretty close twin to the orange boat thats been at the top of Hydroracer site with Troy Christie driving. Its got an ordinary plywood left cockpit side and a balsa/fiberglass right side. We're hoping to race at 380-385 lbs with a 302 and no transom height so it should be exciting for him. But have a 102 crank out for new rods and bearings and have a brand new 102 block so that option is available if needed because everyone knows that the 302s can't beat a good 102 in stock racing. our big debate is to decide to use the Yamoto gas tank or a fuel pump, tank in boat like we've run before.

[jsilvestri]

Steve,
My dad's address is:

225 7th St. N.E.
New Philadelphia, OH 44663

[hydroplay]

I'll have to try laminating a light layer of glass over the kevlar and see if that will allow it to be trimmed or sanded. I've got a bunch of kevlar laying around and that might let me use it I got frustrated making finished edges with it. Even my boy dislikes the edges when it was used to reinforce one of his hockey stick blades.