Carbon limbs

[Nicholi]

Morrison even sells twill carbon on their website.

https://www.morrisonarchery.com/shop-4

[Flem]

If someone is planning on buying carbon fiber fabric or tapes, you might be better off buying from a specialty outfit. I was looking on Morrison's website. They are selling 1.75" carbon twill tape for $28.75 a yard. Composite Envisions sells the comparable product in 3" width for $2.89 a yard

https://compositeenvisions.com/composite-reinforcement-fabrics/carbon-fiber-reinforcements/tapes/

Now that’s exactly the sort of thing I’m after. Will look properly tomorrow but looks like hot stuff!

I’ve been searching the web looking for data sheets on Gordon glass today. I know it’s not CF but I’d like to know the numbers to compare. Couldn’t find anything. Does anyone have one for UL and ULS?

Thanks
Andy

Attached is a pdf of Gordon's composites info, current as of April 2020.


Mark

Nice find Mark! I have been looking for that info from PolyOne, but had no luck.
Gordons UL and ULS are 70% epoxy!

[mmattockx]

Nice find Mark! I have been looking for that info from PolyOne, but had no luck.

Thanks. I got it by emailing PolyOne with questions. It took a while, but I eventually got a reply from their national archery accounts manager with this pdf attached. The guy seemed like a serious archer and experienced bow hunter who knew his product very well.


Mark

[AndyTurner]

You guys are officially faster than PolyOne and Avient! I emailed them yesterday morning.
Do you also have a data sheet on their Carbon?

[Flem]

Its right there on that PDF, its the GC-70-UCL

[AndyTurner]

Sorry I havnt had a chance to read it yet

[AndyTurner]

I just remembered reading about the laminate Buemaker uses. Exel of Finland. Too bad you guys bailed out of the EU, although you might still be able to get their products
Looks like they have carbon fiber laminates for back and belly surfaces

https://exelcomposites.com/wp-content/uploads/2020/06/EN_Exel-Archery-Laminates_Datasheet-2017.pdf

Am I missing something?
1. There is no compression data for any of their products. I know people Generally favour FG for Bellies but some people successfully use CF for belly’s e.g Border. Also do all the FG products behave the same in compression?
2. There is no 90degree data for some of their products. I’m guessing unidirectional products arn’t designed to provide lateral stability but how can you quantify the advantage of the ones that do? The unidirectional stuff must have some lateral properties. They can’t be 0.

I have emailed them. If I get a response I’ll post data.

Thanks
Andy   

[Flem]

No 90deg data for the unidirectional laminates. Would seem to be a moot point.

[AndyTurner]

Well it’s all about gains & trades right?
A. If you only get a 25% gain in lateral stability then you might not bother.
B. If you get a 95% gain in lateral stability then it justifies the weight gain.

[Flem]

What style bow are you going to build, Andy?

[AndyTurner]

What style bow are you going to build, Andy?

Some sort of Hybrid curvy thing. Pic of form attached.

What I would really like is some general advice on working with composites. I posted this in another thread. What do you think?

When building a composite bow, do you use the data sheets to try and build a balanced spring? For example,

GC-70-ULZ has a Tensile strength of 243000PSI. I’d use this for the Back.

GC-70-ULS has a Compressive strength of 119000PSI. I’d use X2 strips of this on the Belly giving 238000PSI

This would provide
243000 working against 238000

This in my "simple head" would give you a "reasonably well Balanced Spring".

Thanks,
Andy

[Flem]

Ive never seen the ULZ for sale, only the UL and ULS. You have a source over there?

[AndyTurner]

Ive never seen the ULZ for sale, only the UL and ULS. You have a source over there?

No just saw it on their data sheet so assumed it would be available

[Mad Max]

I think this was back in the 60's

[Flem]

Actually 3M started making Scotch-Ply in the 50's. It was made from woven material, compression molded.
Some of those old bows you see with the woven pattern, but not embossed, are most likely Scotch-ply.
I don't think anybody made unidirectional laminates suitable for our use until Gordons started.

[AndyTurner]

I don’t know why Gordon’s are still using E-Glass (originally for electrical parts hence E). Structural glass (S-Glass) is significantly better in tension & compression. It’s been around for years.

It’s on the data sheets that someone else posted but doesn’t seem to be available.
It’s the ULZ stuff.

Any ideas?

[Flem]

S-glass is significantly more expensive than E-glass. If you want somebody to start selling it in a retail setting, you will have to create a demand for it.
If you really want some serious performance from your composite bow, you need M-glass on the back and S-glass on the belly.

[AndyTurner]

If you really want some serious performance from your composite bow, you need M-glass on the back and S-glass on the belly.

😂😂😂😂 This is the email I just got from PolyOne. I give up! 😂😂😂

Yes – the S-glass is very special as the strain I about double of e-glass.  But the cost is 7-10 times more per pound.  And it is poor in compression.
 
Most limbs are made of GC-67-UB and possibly have a GC-70-UL laminated/bonded to it if the limb fails etc.
 
It is tricky business.  A lot of dynamic forces and modeling questions. 
 
We do not design limbs or really have any part in it.  We just manufacture the composite and sell it to Bow Builders/OEM’s.
 
I do not know the scale of your project.  Our minimum order quantities are 1000 pieces.  So you will probably have to go to a distributor or something.   www.binghamprojects.com is a good starting point.
 
Thanks
Rob Loveland, PE
Director of Engineering, Gordon Composites
Avient Corporation

Office: +1 970-240-2234
Mobile: +1 970-640-7310
Web: www.avient.com

Avient Corporation formerly PolyOne Corporation
2350 Air Park Way, Montrose, Colorado, USA 81401

[Flem]

Thats why some bowyers make their own laminates. That and the colors available are plain and uninteresting.