Source for Carbon Rods?

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flyndude

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Mar 14, 2021
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Does anyone have a source for carbon rod coils? I can find plenty of places that will sell you cut lengths up to 12 feet but I need much longer for building a spar. A couple of the companies will supply longer lengths but require large orders (3-4000 meters). I had been sourcing them from Jim Marske but he has been trying for the last several months (without any luck) to get resupplied from the company he normally orders from (Goodwinds) that was recently acquired by another firm.
 

flyndude

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I was looking for .092x.220 carbon rods. At $2.30 a foot that would be over 9K and I only need about 300 feet of the stuff. I suppose I could do the calculations for 1/8 round but that would still leave me with a lot of excess rod. I'm still hoping Jim recovers soon and I can buy the length I need from him.
 

BoKu

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I was looking for .092x.220 carbon rods. At $2.30 a foot that would be over 9K and I only need about 300 feet of the stuff. I suppose I could do the calculations for 1/8 round but that would still leave me with a lot of excess rod. I'm still hoping Jim recovers soon and I can buy the length I need from him.
I'm checking out some Chinese suppliers right now for 2mm x 5mm strip. I might buy a bunch for the CarbonMax project, and then design the spars according to test results on whatever they send me. Let me know if you want in on that.

BTW, the first batch of Graphlite strip I bought was $0.55/foot. All other carbon materials have declined in price drastically, but pultrusions have quadrupled. So it's probably time to hunt up a new supplier.
 
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BoKu

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I just ordered 1000m of 2mm (0.079") x 5mm (0.197") carbon flat. We can talk prices in depth after we get test results on strength and stiffness. But preliminarily I'd be pleased to get $75 per 100 feet for it. Because it has only 75% of the cross-section of the .22 x .092 profile we used to get a free ride on, expect to order at least 33% more to get the equivalent cross-section area.
 

BoKu

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Yes, but is this "General Tso's Twice Cooked Carbon Noodle" or is it American with some amount of quality control?
It's from China, like much of the carbon fiber hobbyists have been buying for the last five years. I'll cut samples from each of several spools and have tests done, and we'll see what properties we can expect. I've never designed to more than about 50% of the strength capacity, so there's plenty of margin.
 

Hot Wings

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If the numbers are as good a Goodwind's your source would save around $350 at $75/100ft. for an AV-36 spar. Maybe more if I could optimize a little better with the smaller area rods - and there would be enough left over from the last 100 ft to build some rudder spars as well.

The fact that it comes in a roll rather than by the 12ft stick means less waste too.
 

davidjgall

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I just ordered 1000m of 2mm (0.079") x 5mm (0.197") carbon flat. We can talk prices in depth after we get test results on strength and stiffness. But preliminarily I'd be pleased to get $75 per 100 feet for it. Because it has only 75% of the cross-section of the .22 x .092 profile we used to get a free ride on, expect to order at least 33% more to get the equivalent cross-section area.
Please put me on your customer list, Bob. Thank you.
 

BoKu

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FedEx says the spools of 5mm x 2mm carbon strips should be here on Monday next week; we'll see what they look like when they get here.

Unfortunately the company underestimated the original shipping costs, so the base price would now be $85/100 feet.

If this stuff tests out acceptably (compression is the real bugaboo), I will consider paying the tooling costs and having them make the .092 x .022 size that some of us have hard-tooled for. Although, in the long run it's probably cheaper to scrap the hard tooling and redesign for the now-more-common metric profiles.
 

Hot Wings

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Even at the 13% increase in shipping it still looks like a good deal. For those of us that don't have any hard tooling in place..........

I loaded the data from the Goodwinds site into an Excel sheet. It looks like they value their process far more than the material. Finding the sweet spot between using less small material to optimize material use vs minimizing $$s by using larger rods could be an interesting challenge.
 

BoKu

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Half of the order (500m, ~1640 ft) arrived today. Of course, we need to do tests, but it looks and feels just like the Goodwinds 0.22 x .092 that I've used a couple miles of.

This oddly crunchy hula hoop showed up in the driveway.
20210402_141600.jpg

Looks good so far.
20210402_141756.jpg

Yup, that's four bundles. Invoice says they're 125m (~410 feet) each.
20210402_143038.jpg

The end feels about the same stiffness as the Goodwinds stuff.
20210402_143045.jpg
 
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