Subject: Re: [harryproa] Carbon
From: Dennis Cox
Date: 5/21/2011, 4:45 PM
To: harryproa@yahoogroups.com.au
Reply-to:
harryproa@yahoogroups.com.au

 

Doug,
 
That piece with the glass tow wrapped around was going to be a rudder blank.  It went on real easily and fast... It probably took me less than an hour to wrap it up and since tension is kept on the tow at all times, I'm absolutely sure that there is no waviness.  I don't know if I'll be using that one since Rick's (cambered centerboard concept with smaller, less stressed rudders) has me back at the analysis tools to see what it'll do for me.  I may end up doing one larger daggerboard and two token rudders.
 
Here are some data sheets I use to design around.  The 12K IM7 is the stuff that we can get for around $10/pound plus shipping.  I haven't found a good source for this particular fiberglass, but its a start.
 
Carbon
http://www.hexcel.com/Resources/Cont-Carbon-Fiber-Data-Sheets
Fiberglass
http://www.owenscorningchina.com/upload/File/655040920.pdf
 
From what I can find, glass is about 1/10th the price... but you have to pretty much re-design things relative to a carbon version.
 
Dennis 
 
 
 

From: Doug Haines <doha720@yahoo.co.uk>
To: harryproa@yahoogroups.com.au
Sent: Fri, May 20, 2011 10:05:23 PM
Subject: Re: [harryproa] Carbon

 

Hi Dennis,
 
You used that glass tow on that board (rudder board) n the pictures on file under MLM, so was that stuff not too thick and stiff?
The carbon that Rob gave me was much thinner and softer.
 
What were you going to do with it?
 
I like to use the uni 400g glass quite a lot of the times, when needing uni.
You get a lot more on in quicker time.
 
You can easily cut strips to the width required.
 
What was the property of carbon compared to glass again?
 
Doug

--- On Sat, 21/5/11, Dennis Cox <dec720@att.net> wrote:

From: Dennis Cox <dec720@att.net>
Subject: Re: [harryproa] Carbon
To: harryproa@yahoogroups.com.au
Date: Saturday, 21 May, 2011, 0:04

 
That's the issue... do I trust the seller.  I was hoping someone here had a vendor they could recommend. 
 
Also, after my last email, I though I'd get a 1 lb roll just to try out some ideas before I commit to a larger purchase.  Apparently S&H is pretty high...
 
Shipped prices
1 lb - $24
10.4 lb - $131
 
I guess I'll wait till I know how much I need!
 
 
From: Rob Denney <harryproa@gmail.com>
To: harryproa@yahoogroups.com.au
Sent: Fri, May 20, 2011 8:47:46 AM
Subject: Re: [harryproa] Carbon

 
Tow is good for filament winding (irrelevant for us) , for local reinforcing and for loads that are applied in two directions, such as curved beams where the uni tends to crimp on the inside of the curve.  Uni is easier to use for masts but  twice or more the price.  Tow is very good if you have a wet out machine, but hard work to infuse in masts.

$10/lb is a good price.  IM7 is higher strength than the standard modulus stuff I use, so go for it, if you trust the seller.  The 6 or 12k will be easier to wet out than the 50K stuff I use, but you will need more runs.  Will save a lot of walking if you use multiple spools at the same time.

rob

On Fri, May 20, 2011 at 10:18 PM, Gardner Pomper <gardner@networknow.org> wrote:
 
What are the tradeoffs between tow and uni fabric? I would assume that the uni is easier to work with for most things. Is it just a pricing difference? How much more is uni than the equivalent tow? Can you give some examples?

- Gardner

On Fri, May 20, 2011 at 7:53 AM, Rob Denney <harryproa@gmail.com> wrote:
 
Ebay usually has some.

Or,  I am about to order some.  If a 12 pound spool is not too much, let me know tonight and I can include another roll in the order.

rob


On Fri, May 20, 2011 at 9:43 PM, Dennis Cox <dec720@att.net> wrote:
 
I'm sure this has been asked before and probably by me... but has anyone found any good sources recently for carbon tow here in the US?  I mean specifically SMALL quantities... < 10 lbs.
 
Thanks



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