Carbon Fibre

[jeffhigh]

Hi Trevor
I am new at using carbon fibre in any form other than CF/epoxy preformed.
In the book you call for using cloth and strands from "cloth woven from 198gm/1000m yarn"
I can't find cloth listed in these terms but I can find plain weave 198gm/m2 woven from 3 k tow
As far as I can work out 3k tow is about 200gm /100m
Is this the right one?

[Trevor Gore]

Jeff, the actual product I use is called "198G TORAY" (Toray is a company that makes CF). I get it from Fiber glass international and their product code is F02338. The FGI product catalogue is available from here: http://www.fgi.com.au/?q=fgi-product-catalogue and download "High Performance Fabrics".

I researched the Toray carbon fibre website (which seems to no longer exist, http://www.toraycfa.com/) to specify the product in more general terms and came up with the designation in the book. At this stage, I can't check whether it was right or wrong, but I remember being pretty thorough about it at the time.

I hope that helps.

Cheers, Trevor.

[ScottC.]

Hey Trevor, I am not having any luck with these websites, any other ideas where to look for for carbon fiber cloth?
Thanks

[Tod Gilding]

Also Trevor would you please look at these and let me know if it is suitable .

Tow for braceing http://www.carbonfiber.com.au/category9_1.htm

Bridge plate http://www.carbonfiber.com.au/category4_1.htm

Thankyou and Cheers

[Trevor Gore]

It looks like Fibreglass International has changed its name to Nuplex Composites. In Sydney area, they're still at the same place:

14 Clearview Place
Brookvale NSW 2100
Postal: PO Box 392
Brookvale NSW 2100

Tel: (02) 9939 1399
Fax: (02) 9938 5826

http://www.nuplexcomposites.com/australia/?q=node/6

Give them a call and see if they still stock the stuff I mentioned above. Whilst you're at it, try to get the equivalent tow numbers and let us all know!!

Tod, I've not used those products so can't really say anything about them. Would suggest calling Nuplex as above.

[Dominic]

I have some 75mm wide cf tape that is called 200gm/sqm. Can't see much difference between 198 and 200. Looks about the right size. Most hobby/model shops have this stuff. For hobby type applications this cloth seems the most common size/weight.

You only want a simple weave, not bi directional or twill or its harder to pull apart and the rove will have folds and twists in it.

Cheers
Dom

[ScottC.]

Hi Trevor
I am new at using carbon fibre in any form other than CF/epoxy preformed.
In the book you call for using cloth and strands from "cloth woven from 198gm/1000m yarn"
I can't find cloth listed in these terms but I can find plain weave 198gm/m2 woven from 3 k tow
As far as I can work out 3k tow is about 200gm /100m
Is this the right one?

Jeff, where is that in the book,I couldn't find it, Thanks

[ScottC.]

I have some 75mm wide cf tape that is called 200gm/sqm. Can't see much difference between 198 and 200. Looks about the right size. Most hobby/model shops have this stuff. For hobby type applications this cloth seems the most common size/weight.

You only want a simple weave, not bi directional or twill or its harder to pull apart and the rove will have folds and twists in it.

Cheers
Dom

Hey Dom, what would it be used for hobby wise?
Thanks

[ScottC.]

Would a regular 5 minute epoxy work for laminating CF fabric and walnut together for a bridge?

[jeffhigh]

No, it does not cure hard enough. get some proper stuff.

[ScottC.]

Thanks Jeff, what do you mean "proper stuff"?

[Trevor Gore]

West 106 resin with 206 slow hardener for laying up or 207 special coatings hardener for clear coat/pore fill.

[ScottC.]

West 106 resin with 206 slow hardener for laying up or 207 special coatings hardener for clear coat/pore fill.

I couldn't find West 106 only 105, but I did find 206.

[Trevor Gore]

Sorry Scott. That should have been 105 resin. Apologies.

Don't use the 206 hardener on pore fills/clear coatings. It has a tendency to bloom down the track, whereas the 207 is formulated to avoid that.

[ScottC.]

I think I'll just use the the stuff for making laminated bridge pieces.

[Trevor Gore]

I've had some more enquiries about the specification of the carbon fibre that I use and after a lengthy search I managed to get the following information from the Toray website. I can't get a link to work directly to the correct page, however this:

http://www.torayca.com/en/index.html

gets you close. From here, look for the "Product lineup" panel on the right and hit "more details" under "Torayca Fabrics" and it will take you to a table of cloth specs. The product I am using is either the CO6343 or the CO6343B. I don't know what the difference is between these two, other than the B designation of the yarn. It may contain a binder (???)

You can get the material properties of the fibre by hitting "more details" under "Torayca Carbon Fiber" again, in the panel on the right.

The fibre is 3k tow, 198 gram/1000m, which is what it says in the book.

Here is a summary table of the products:

Toray Table Small.jpg (34.58 KiB) Viewed 34273 times

Now you should be able to source something similar wherever you live. The strands that I use for overlaying braces are just yarns (which contain 3000 fibres) pulled from the woven cloth.

[ScottC.]

Hey, I found some with similar specs
http://www.solarcomposites.com/composit ... on.html#3K

[woodrat]

Hi Trevor, I am using 12K tow that I got from a guy in the UK...it is called IM9 and is an industrial roving ....What difference would there be in using 4 times the fibre and I seem to be doing...?? I have my second Falcate box closed and it taps out at about 185Hz without the bridge...I amusing 9mm high braces so I am surprised that I am so low. I didnt do any edge thinning on my last one either because I was at 180Hz sans bridge... I barely did any on this one but it dropped 4 Hz .You mentioned that you always seem to come out on the stiff side. I think that I will go up to 10mm high and see if that brings me higher at the bound box stage...Everything seems good otherwise

John

[Trevor Gore]

John, if you have found a method/materials that work for you, stick with it. That's basically what I did. There's no harm in using more CF if the mode frequencies are in the right places.

You mentioned that you always seem to come out on the stiff side.

I'm still not sure why that always happens, but it always does. I don't have any better materials than anyone else, so all I can put it down to is working really clean, gluing only fresh surfaces and making really closely fitting joints. On the other hand, using mainly hand planes might be having more effect than I've been giving credit for. For sure it helps with the tight joints, but might also be causing less fibre damage than sanding, even after going through all the grit grades. I saw a guitar a while ago where the top had been sanded to thickness, with the braces glued straight on to that surface. So there's ~0.5mm of plate thickness on the inside of that guitar incapable of doing anything but adding mass.

[woodrat]

I may not have given enough credence to the planed vs sanded surfaces factor. I glued my laminates together from sanded pieces. So my nominal 5 mm thick braces may in reality be 4.5ish...Hmmm...It is not much but I will make sure I switch to only planed surfaces for this and see how I go. If suddenly I spike up to ~200Hz using this technique at the closed box/unthinned edge edge stage then I know there possibly has been a discovery made:) Lutherie at the micro level indeed....any advances to the Nano? ...I love it!

John

[charangohabsburg]

[...] I saw a guitar a while ago where the top had been sanded to thickness, with the braces glued straight on to that surface. So there's ~0.5mm of plate thickness on the inside of that guitar incapable of doing anything but adding mass.

Wow! I imagined this would be quite a bit less than half a millimetre! How do you determine or estimate the only-mass-adding thickness? Is this typical approximate value you got from your free plate measuring respectively free plate tap recordings (when figuring out the modulus of elasticity of a top half)?

[Trevor Gore]

The ~0.5mm was a "guestimate" based on grit particle size. A wide-belt sander in stock removal mode could be using abrasives of 40 (coarse) to 60 (typ.) to 80 (also fairly typ.). The grit average diameters are ~0.45mm, ~0.27mm and ~0.2mm. Add a bit of dispersion (less with higher quality abrasives) and you can see how you could get to ~0.5mm of ploughed up surface and subsurface damage. The top I was referring to I would guess was sanded to 60 grit at best - it was real easy to see the furrows!

[charangohabsburg]

Thank you Trevor. There was obviously no scientific laboratory work necessary when you figured out these numbers. That 60 grit final sanding sounds really impressive (at least when reading about it but maybe not that much when playing that guitar) and was something beyond my imagination.

[kiwigeo]

I've just ordered some 12K CF tow from this mob: http://www.carbonfiber.com.au/

Will report back on service and suitability of product.

[J.F. Custom]

Hey Martin.

I've ordered some tow, tubes and rods from them a few times previously.

Limited range unfortunately, but decent prices and orders have only taken a few days.

Jeremy.