Carbon Fiber vs Fiber Glass

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skidesmond
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Carbon Fiber vs Fiber Glass

Post by skidesmond » Wed Aug 01, 2012 6:50 pm

(Edit - updated with more details)

This thread is a continuation of sorts of a previous thread "Experiment Poly-U Glue vs Epoxy" http://www.skibuilders.com/phpBB2/viewtopic.php?t=3024

But since I'm not using Poly-U glue in the CF test and comparing CF vs FG I thought it be better to start a new thread.

We can be fairly confident from the start that pound for pound (ie ounce for ounce) CF is stronger/stiffer/lighter than FG. This allows you to make a lighter ski yet just as durable as a FG ski. But how much lighter, stronger, durable?

Here's the test I conducted with CF sample layups and comparing them to the FG layups I did in the "Experiment Poly-U Glue vs Epoxy".

A few notable Ooops.....
1. In the CF test samples I forgot to use VDS which I used in the FG test samples (argh).
2. The CF samples I used poplar veneer instead of maple. I thought I had used poplar in the original FG samples.
3. I did not do a CF and metal layup. Instead I did a CF and FG layup and compared that against the FG metal layup. WHY? Chances are I won't be using metal (titanal or AL) in a ski any time soon. The comparison results of the 2 are intriguing though.

All materials below measure 3in wide x 36in long (76.2mm x 914.4mm).

Material list for the FG layup:
FG - Triax 20 oz with 7 carbon fiber strips
Core - maple 1/16in thick (1.6mm) 2 layers in each sample
Cork - .8mm (www.corkstore.com)
AL - .24mm thick (sanded using 80 grit to increase adhesion)
Epoxy - QCM EMV 0049 resin ECA 032 hardener
VDS
Ptex base

Material list for the CF layup:
CF - 9.4oz Uni
FG - Triax 22 oz
Core - poplar 1/16in thick (1.6mm) 2 layers in each sample
Cork - .8mm (www.corkstore.com)
Epoxy - QCM EMV 0049 resin ECA 032 hardener
Ptex base

30lb weight (13.6 kilo)
Wixey Digital Angle gauge model WR300 to measure angle of deflection

All samples were pressed and cured at room temp.

As you can see the CF is a little bit lighter, slightly thinner and retained more camber out of the press with 1 exception.

Image


Defelection Test Results:
I used the BOW method to conduct the Deflection test... Bucket Of Weights :-) See my hi-tech method in the above link.

Here you can see how much stronger the CF is when 30lbs of weight is applied to each CF sample. Hands down it is stronger. The CF/FG layup deflected less than the FG/metal layup which was a little bit of a surprise.

Image


Torsion Test Results:
The torsional tests are fairly close. I'm assuming this is because the FG is triaxial/heavier and the CF is only Uni. The FG Cork is a very weak layup and the cork does nothing for torsional stiffness as expected.
Image


CF FG Comparison:
These charts are just the above charts combined.

Image


So, as expected CF will create a lighter, stiffer ski. You can bet I will make at least 1 ski that is just CF and 1 CF/FG ski this season!

Well that's it for now.
Last edited by skidesmond on Thu Aug 02, 2012 1:35 pm, edited 2 times in total.

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MontuckyMadman
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Post by MontuckyMadman » Thu Aug 02, 2012 11:29 am

some more details would be nice like weight of glas and size of test sample/core and type of epoxy and thickness of metal and you might have different results if cured quickly under heat.
aside from that good stuff.
I think something should also be pointed out with relation to terminology.
The CF samples are perhaps not stronger but stiffer.
A failure test under load would determine actual strength over stiffness i think.
just my opinion.
sammer wrote: I'm still a tang on top guy.

skidesmond
Posts: 2320
Joined: Tue Apr 07, 2009 3:26 pm
Location: Western Mass, USA
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Post by skidesmond » Thu Aug 02, 2012 12:53 pm

yeah I was a bit lazy with the details and just put the link w/ that info from my other post. I'll update this one w/ more details so it's more concise.

Correction, CF is stiffer. A failure test under load would be very interesting. Need figure out how to do it. I have a $hit load of bricks.... :-)

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