Surfriding Carbon reinforcement?

[High Speed Industries]

I will be getting a super jet in the near future and I plan on making it into a surf/flatwater boat. I need some input for reinforcing hull. I want to keep it relatively light so my thought was to use carbon fiber instead. I have tried searching for the answer but people only seem to use carbon for looks. So here was my plan.
Scrape out old bond line glue/ fill bond line with cabosil

Use epoxy resin

Use 11oz 2x2 twill carbon

Three layers in the nose/pole area and two layers on the sides

But here are some of my questions
Is that the carbon I should be using?

Do I need 3 layers in the front and 2 on the sides? Should I do more/less layers?

How many yards of carbon should I buy?

How much resin should I buy?

And finally should I even waste my time with carbon? I know it costs more but I am trying to keep this ski relatively light.
All input is helpful.
Thanks.

 

[swapmeet]

I'm kinda in the same boat brah.....
I'm thinking about doing a layer of kevlar with Carbon on top of that.


Sollercomposites.com has some great deals on CF.

Hopefully you get some answers. Answers are good.

















Brah.

 

[High Speed Industries]

Yea brah answers are good. I was looking at buying from uscomposites.com. I'm sure there are other websites that offer good deals too. Just don't buy from blow$ion. They want too much $$$. In the end I just don't want to add 100+ pounds to a ski if it's not needed.

 

[swapmeet]

Yeah, i'm getting a lot of the non-cloth products from USComp... foam, resin, cabosil etc.

 

[djraider700]

A surf AND flatwater SJ? Hope you plan on a big motor for flatwater stuff if you're looking to do flips.

I don't really think there is going to be much difference between fiberglass and carbon weight-wise. But, then again, every little bit helps. The biggest thing I've noticed is to make sure you squeeze as much resin out of the layup as you can. You don't want that gooped all over and adding unnecessary weight.

 

[High Speed Industries]

A surf AND flatwater SJ? Hope you plan on a big motor for flatwater stuff if you're looking to do flips.

I don't really think there is going to be much difference between fiberglass and carbon weight-wise. But, then again, every little bit helps. The biggest thing I've noticed is to make sure you squeeze as much resin out of the layup as you can. You don't want that gooped all over and adding unnecessary weight.

No flat water flips for me. If I want that I will buy a bob. Just trying to see how light I can make it without the reinforcement being too weak.

 

[High Speed Industries]

I've also been told that carbon is too stuff to use as reinforcement. I guess it can separate from the hull because they both flex differently. What I got out of the conversation was that carbon is just for looks.

 

[kevbo]

I will be getting a super jet in the near future and I plan on making it into a surf/flatwater boat. I need some input for reinforcing hull. I want to keep it relatively light so my thought was to use carbon fiber instead. I have tried searching for the answer but people only seem to use carbon for looks. So here was my plan.
Scrape out old bond line glue/ fill bond line with cabosil

Use epoxy resin

Use 11oz 2x2 twill carbon

Three layers in the nose/pole area and two layers on the sides

But here are some of my questions
Is that the carbon I should be using?

Do I need 3 layers in the front and 2 on the sides? Should I do more/less layers?

How many yards of carbon should I buy?

How much resin should I buy?

And finally should I even waste my time with carbon? I know it costs more but I am trying to keep this ski relatively light.
All input is helpful.
Thanks.

2X2 weave follows curves easier than plain weave. Two layers of 11oz cloth is plenty for the sides. You will have issues controlling resin because the fiber will bulk up and excess resin will pool in low areas. One way to help with this is by laying a layer of nylon cloth (peel ply) over the completed layup. This will draw out some excess resin and allow you to move it around and work out bubbles with a spreader. After curing the peel ply can be pulled off and the surface will have a smooth satin finish. Make sure to clean and scuff everything with 120 grit, there can be no greasy or shinny spots.

 

[Profound-Dynamics]

With the amount of reenforcing your going to do, using carbon vs glass really isn't going to produce much of a weight different. Your looking at some difference when you are building a complete hull out of one material for the other.

I'd jut use glass than maybe a layer of carbon over the top if you want to have some visual appeal. But as far as going to carbon for just a weight savings is ridiculous especially considering the additional cost of carbon over glass.

When I reenforced my boat, I did about 60 oz of reenforcement in the nose and pole bracket and about 40 on the sides. I only weighted in at a couple pounds more. Much less that I anticipated.

I didn't reenforce still I started getting a lot of stress cracks around the Hood loops from rolls in CA surf.

 

[High Speed Industries]

So should I just go with some 1208 biaxial fiber glass? How thick? 3 layers up front and 2 layers on the sides?

 

[kevbo]

So should I just go with some 1208 biaxial fiber glass? How thick? 3 layers up front and 2 layers on the sides?

1208 is only used because it is so cheap. It will work but if you want to do a nice job use 3-4 layers of 7781.

 

[Flash-FX]

http://www.x-h2o.com/threads/93167-Stupid-carbon-fiber-question....Follow the white rabbit....

 

[harris414]

1208 is only used because it is so cheap. It will work but if you want to do a nice job use 3-4 layers of 7781.

X2

the 7781 will give you great strength with out having to build up a heavy thick 1208 to do the same thing...
not sure if it was stated but use epoxy and thicken some epoxy w/micro balloons to fill the crack first so you seal her up and also lets the fabric lay nice and flush. If you can rig up a setup to vacuum bag it I highly suggest it! it can be done using several things if you get creative, any vacuum is better than none...

Let me know if you cant find 7781 by the yard, I have several rolls of it from a composite company doing work for boeing.
F3 finish (Volan). 10oz/sq yd, 38" Wide, .008" Thick, 8H Satin Weave

 

[High Speed Industries]

X2

the 7781 will give you great strength with out having to build up a heavy thick 1208 to do the same thing...
not sure if it was stated but use epoxy and thicken some epoxy w/micro balloons to fill the crack first so you seal her up and also lets the fabric lay nice and flush. If you can rig up a setup to vacuum bag it I highly suggest it! it can be done using several things if you get creative, any vacuum is better than none...

Let me know if you cant find 7781 by the yard, I have several rolls of it from a composite company doing work for boeing.
F3 finish (Volan). 10oz/sq yd, 38" Wide, .008" Thick, 8H Satin Weave

Ok. So it sounds like glass is the way to go as far as strength. It sounds like carbon is for looks. What interests me is the vacuum bagging setup your talking about. Any suggestions on how to do it?

 

[kevbo]

Ok. So it sounds like glass is the way to go as far as strength. It sounds like carbon is for looks. What interests me is the vacuum bagging setup your talking about. Any suggestions on how to do it?

Actually carbon if good stuff just not very economical for a little reinforcement. You will spend $200 on carbon and then have to bleed out excess resin in order to fully realize its advantage. Laying in $30 of decent glass will get the same results and be 2-3lbs heavier. Bagging your work can produce better results but it takes some equipment, material, and experience to be successful. Peel ply will help the layup be more uniform without vacuum bagging. I recommend that for first timers.

 

[High Speed Industries]

I think I will stick to glass. It sounds like carbon is just for the bling. Only other question I have is should I glass the bottom of my engine bay? I that see everyone does the nose and sides but only some people glass the bottom? Is it really that much stronger? It just sounds like extra weight to me.

 

[kevbo]

I think I will stick to glass. It sounds like carbon is just for the bling. Only other question I have is should I glass the bottom of my engine bay? I that see everyone does the nose and sides but only some people glass the bottom? Is it really that much stronger? It just sounds like extra weight to me.

Normally sides are the weak link, side landings were never intended by the mfg so they are very thin compared to the bottom.

 

[High Speed Industries]

Ok. So just stick to the nose and sides. I guess it's always best to keep it simple.

 

[High Speed Industries]

Ok so to do 4 layers of 7781 in the front and 3 layers on the sides how many yards should I buy? I was thinking 8 yards but it almost sounds like too much.

 

[FearMyWrX]

At a couple dollars a yard, it doesn't hurt to have some extra. Nothing sucks more than setting back your project or not having enough to lay up. Im sure you will find a use for the extra cloth anyways.