stack and taper

[B-JS]

Had this, too.
Good consistency.

And, of corse it's WAY better than Stabilcore.
Because this is 45/45 Carbon.
And Stabilcore is just 90/0 Glass.

[Crooked Stic]

Do we think srablecore would be better 45/45 ?

[onetone]

I think it would be better for torsional stability.

[Kirkll]

I have had no trouble with it being consistent. My trade bow has it in the limbs and was tiller dead on both ends right out of the form. And a lot more stable than stablecore.8 pieces with shipping from China $200.

I just ordered 8 pcs of the 5 mm (.019) myself and will be trying it on some light draw weight static tip RC limbs as soon as I get the stuff. I think I’m going to use the stable core with this stuff, only put the carbon next to the belly glass and stable core towards the back. I think it may do better having that 45/45 towards the belly…… we shall see. I’ll mix up the second lay up and see if it makes a difference.

Another lay up I’d like to try is using this stuff on the back instead of glass over stable core. The total composite thickness would be .034 with the carbon and stable core…. This could be used on limbs up to 55-60# me thinks….    Kirk

[Jeff Freeman]

I would be interested in trying on the back and belly, no glass on a Longbow. Just for curiosity and looks

[Bryan Adolphe]

Had this, too.
Good consistency.

And, of corse it's WAY better than Stabilcore.
Because this is 45/45 Carbon.
And Stabilcore is just 90/0 Glass.

Hi sorry can you explain the 45/45 and the 90/0 ? For me please ! 

[Crooked Stic]

Kirk why do you think it will be best towards the belly?
Jeff being only .019 with no glass might not be enough actually just the twill adds no stiffness just stability. You can get 6 ply .050 with uni. On the front and just twill on the belly and get by with no glass. Think that is what Widow does on their carbon limbs.

[Crooked Stic]

90 is in the limb with fibers running the length of the limb and fibers woven in across the limb at 90 degrees. I am thinking the other is also layed up 90 then cut at a 45 to get the strips and when glued in the limb lay at 45. Pull up1 some pics of a black widow carbon limb and see the 45.

[Kirkll]

I would be interested in trying on the back and belly, no glass on a Longbow. Just for curiosity and looks

You want to be very careful putting carbon on the belly side of a bow limb. You can get away with it on some D shape long bow designs that the over all limb flexes and distributes the load more evenly. And even on some mild R/D long bow designs. Typically uni carbon is used for this on a deep core design.....

But... on hybrid R/D long bows where the working limb is shorter, or on recurve limbs.....The Belly side carbon will often separate and shear the bond. Even using rock hard maple as a belly lam. The stuff doesn't compress, and the maple does.... Then it buckles the carbon after the bond is compromised. and BOOM! Thar she blows mate!.... They are time bombs... Ya never know when they are going to let go...And they always blow after the belly carbon buckles...

On the other hand .....it makes for some great explosive limb failures worth getting on video.


As far as putting this stuff on the back of a limb with no glass... I think you'd  find it will work just fine. I've built bow limbs with 2 layers of stable core alone on the back and it wasn't purdy , but was successful... I don't know whether it would hold up under compression on the belly side though...Never tried that.

  I'm going to try this new .019 stuff on the back over stable core for a total of .034 composite backing. I'll bet does well for 35-55# limbs.....

But i'm thinking the lighter weight recurves might get better stability with a slight separation between the carbon and the stable core......I'll try it both ways. Carbon next to the belly under .030 glass, and stable core towards the back. The switch it up on the next lay up...

The reason i think the stability might be better with the carbon towards the belly comes from past experience building single and double carbon bows. If you could put it on the belly itself without building a bomb, THAT will give you serious torsional strength.... But i'm not going back down that expensive rabbit hole again... Been there... done that... Too expensive to be replacing on warranty.... It's not a matter of IF they will blow.... Its just a matter of when...   Need glass on the belly for longevity and fine tuning your limbs draw weight and balance... You cant sand that carbon for adjustment. It is... What it is...

Big outfits that mass produce double carbon limbs have to match them up as close as possible, and send them out the door praying they make it until the warranty expires, or the customer hangs it on his wall instead of shooting it a lot... They are all time bombs...   

That's about  10 cents worth of my opinion... Take it or leave it......     Kirk

[Crooked Stic]

You got to keep the uni off the belly.  The only reason I use carbon is for stability Front and belly .020 or the  019 over glass. Thinking Widow uses 6 ply front no glass and 2 ply twill belly no glass. The 6 ply has uni and twill.

[Kirkll]

You got to keep the uni off the belly.  The only reason I use carbon is for stability Front and belly .020 or the  019 over glass. Thinking Widow uses 6 ply front no glass and 2 ply twill belly no glass. The 6 ply has uni and twill.

So you are saying you use this directly on the belly and back directly over the .040 glass? If so, how do you adjust draw weight , and balance your limbs without sanding?  Width profile and trapping only?

[Crooked Stic]

If I want the carbon look yes front and back and I put it over .030 core tuff. Only had one recurve had to adjust the tiller and got enough off the corners to take care of it.
If you are going for stability only put it under veneers .⁵

[Longcruise]

This discussion has me thinking that for stability only,  maybe putting the hex close to the neutral plane would be a good choice.  I've been putting stabilcore on the belly side.  Some say they put it on the back side.

[Jeff Freeman]

I've a gone from what I've heard.  It goes on the back or one under the back. Not the belly, because it doesn't like compression. Unless it's the proper carbon. IDK about the belly. I put some stabil core on the back 🔙 under .030 glass and I did get some better speed. But I also used 1 laminations of syntactic foam. I was to chicken shit to do both laminations. So one was maple on the belly. Now I wished I would have done both foam. And .040 on the belly. It was in the 190s fps.  This was on a 62" hybrid. I called it, Project X. JF

[onetone]

This discussion has me thinking that for stability only,  maybe putting the hex close to the neutral plane would be a good choice.  I've been putting stabilcore on the belly side.  Some say they put it on the back side.

When I use it, I always put stabilkore in the center of the stack for rotational stability and would do the same with the twill carbon. The center of the limb seems like a good place to minimize rotation. Just what works for me.

[Mad Max]

My thinking that putting Stabil-kore next to the belly glass or veneer (because It's so flimsy)would work better because you are compressing it.
 

[Crooked Stic]

To be truthful I have not seen a case where I thought stablecore has done that much good.

[Kirkll]

Torsional stability is very difficult to measure from one bow to the next. Where you really start noticing difference is in RC bows under 40 @ 28… under 35 pounds it’s even more pronounced as the limbs get thinner at the base of the curl .

For me the thickness that things start getting squirrelly is getting below .190 at the base of the curl. On light weight bows I’ll use par lams or even reverse taper to keep that thickness.

I’m hoping this cost effective 45/45 bias will mitigate this.  Once you start using a reverse taper, it changes your limb dynamics a lot and it bends  closer to the fades….

We shall see….  Kirk

[Kirkll]

My thinking that putting Stabil-kore next to the belly glass or veneer (because It's so flimsy)would work better because you are compressing it.

That is my thinking too….and it should be amplified with 45/45 carbon weave. But this China carbon is different material than I’ve used in the past.

I got a bit more info from the supplier in China regarding this 45/45 bias carbon. There are only two layers of carbon in the .019 thickness. Both being bias. I’m uncertain whether this is a pre preg material or not, but all the lay ups that I had built at CST and other west coast carbon manufacturers used pre preg material and the thickness was about .0065 per layer. So getting a .019 thickness would require 3 layers.  I ordered quite a bit of. “XOX” lay up which was 45/uni/45 that measured about .021 . But…… I had a tough time keeping that stuff directly on the belly of a recurve limbs and hybrid limbs both. even used over glass I had shearing issues due to compression.

I won’t be using this stuff on the belly surface myself. Not worth the heart break. I’ll put it directly under .030 belly glass  and see how it does for added stability.

Kirk

[Mad Max]