I've got three bows with "carbon limbs"...two are Hoyt target bows from the 80s, one is a Sentman longbow. None of these bows are staggering speedwise but Hoyt thought way back then that carbon contributed limb stability and Gary Sentman has suggested on LW that carbon didn't actually contribute much to his already high- performance longbows. I think today's wisdom around carbon limbs holds that the type of carbon and the way it's laid is...tricky.

Carbon is best under compression, doesn't do much on the back.

Bob

Are you thinking of adding a carbon layer to a existing bow? Seems like that would not be the most effective use of the material. If it's for cosmetic reasons, they make woven as thin as .004.

Patrick is right that carbon works best under tension not compression. How much draw weight it would add depends on the design of the limb. Like Steve I fell it would not be the most effective use of the material. Marc,

It would be a waste of time and money. The additional weight of the carbon on the already likely already heavy limb would cancel any significant improvement and may in fact make the bow slower.

The addition of linear carbon on the back, over fiberglass, will likely add significant draw weight to your bow. It will be like adding more than a .050 layer of glass. The reason is that when used on the outside of a lam stack, carbon can not elongate or compress without failure. Linear carbon is only valid on the exterior of a lam stack. Buried in the stack it does nothing but slide back and forth with glue creep and will only increase draw weight the same as the equal thickness in wood. Balanced woven's can be used in a stack to provide torsional stability, something a longbow does not need, by design.

My Howard Hill Special Edition Black Mamba has a layer of carbon on the back. Ken

I have made reflex deflex bows for my son, and some of his friends.Made some with just bamboo for the lams under clear glass.Others by request same design with one carbon layer under clear glass on the back of the bow.Not much difference that i could see except for a different look color wise, and the carbon costs more.For that matter i have made that same bow with maple core lams, and never really saw that much difference between that and boo lambs.Now, all carbon foam core limbs there is a difference they pull smoother, and shoot faster and are noisy with a metal riser.JMHO.

I have two longbows made by the same guy , one has carbon lams the other doesn't. World of difference shooting them. The carbon lams are a great addition to the bow. Smoother draw and faster shooting at the same draw weight. They are definitely worth the addition but not sure on an existing bow. Mine has 3 layers.

Yes with 3 layers of carbon it would make a difference,but he was talking one layer on the outside on the the back of the bow.I understand why you like carbon in those proportions.Good shooting.

JK- Gary here. In response to the carbon limb mentioned above. Adding carbon to a traditional wood core bow, in my opinion, adds very little speed. It is not tricky at all to use it simply must be used on the expansion back side of the bow. I have always put it under the back glass. Carbon becomes less efficient in deep core limbs. Carbon is more efficient in wide thin limbs. Carbon adds considerably more limb stability but should be used in moderation depending on the core, limb width and pull weight. In short, carbon in a Hill type bow 60#’s plus is not necessary for limb stability. However, carbon used in this type of limb reduces the wood core tremendously and therefore, apples to apples will reduce hand shock to a degree. From my past observations the archer that does not like carbon in a traditional bow does not like a stiff feeling draw. Carbon is inclined to make a bow feel heavier and stiffer per say. I will close this statement by saying most of my bows on my bow rack today, regardless of design, have carbon under the back black glass of the bow. Moosejaw Gary Sentman

I have responded to the response from JK and now to respond to the original question. To add carbon to an existing bow is sure to end in failure. Carbon is soft almost like pencil lead and as an exterior skin it is bound to delaminate or fracture in time. Moosejaw Gary Sentman

So carbon on the back but under the glass,Right? Not between the laminations. >>>----> Ken

Yes according to what i have read makes a difference when it is closest to the back of the bow under the glass.Still looking to see the difference.

This is additional information I’d like to share. My friend, the late Jim Brakenberry, was one of the first to test carbon in the limb. At first he had very little comments and said from his tests, in some cases, he got 3’ per second faster. I was also interested in testing the carbon. I was writing for a magazine in these years and wanted to make sure I got my information correct. So I made a couple phone calls to the carbon manufacturers and asked them what their recommendations were. I gave you their recommendation in my past post. On my own, however, I am the kind of guy that has a tendency to think if a little bit is good a lot more would be better. I made 3 bows. One of which had carbon on the back, a wood core and then carbon on the belly and no glass. One of the other bows had carbon on the back instead of a glass lam. The third bow had carbon in the core of the limb. In short within a year all 3 bows delaminates or broke. Keep in mind this was 30+ years ago when I did this. All 3 bows were Hill style with at least a 23” working limb.

I’d like to share a short story: The bow with the carbon on the back and on the belly with a wood core was very impressive. I took it to a big traditional archery tournament to compete. I was standing around before the shoot bahooing to other shooters, some recurve, about how rugged, accurate and dependable the longbow was over the recurve. I was shooting in a large group with about 8 other archers and I was shooting quite well. I was continuing to let everyone know how great my bow was and all. I think it was the 7th target in the course. I was shooting at a 3D target down hill about 30 yards when at full draw my super longbow with carbon all but shattered. You would think the group would have burst into laughter but it actually got pin drop quiet. One of the shooters that was shooting a recurve bow casually asked me “How come your bow blew up”. The group was polite enough to say they would sit under a shade tree and wait for me to retrieve another bow. I beat feet back to the car and fortunately had a spar one. So as the scriptures say “ pride cometh before the fall”. Moosejaw Gary Sentman

Moosejaw ,my bows were built more like longbows,skinny thick limbs,so for other designs it may work much better.My ilf foam core carbon limbed Fivics recurve performs better than any bow i have hanging on my wall. So i know that there is something to this carbon thing.

Gary/Moosejaw..thanks for refining/correcting what I thought I understood about your views/experience with carbon.

I continue to love my 60# Sentman Carbon Deluxe (inscribed "Blackbird" and wouldn't be surprised if you made it a long time ago.

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