# Carbon/Wood vs. Carbon/Foam Limbs



## Jason22 (Aug 16, 2008)

I find it interesting how many elite archers still use limbs that contain wood.
Even with the upcoming 2 limbs from W&W they recommend the wood limbs for advanced archers, but made the foam limbs because many people want it.

At least 13 Olympic medals were won in Beijing with limbs containing wood.


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## engtee (Oct 2, 2003)

I know, from talking to a couple of the elite U.S. archers who prefer wood core limbs, that their main concern is stability. They are able to pull so much weight and have such long draws that the claimed extra speed from foam core limbs is not an issue. When I asked about temperature and humidity being a factor, it seemed to be a non-issue, and realize that these archers shoot all over the world in different conditions.
My personal experience is that I prefer the feel of wood core limbs, but with my short draw length I have found the foam to be faster. When I moved to Arizona, I owned some wood core limbs and after just a couple of hours shooting in the hot sun here, I saw that the limbs seemed to be losing sight marks. I am not willing to condemn the limbs because it was more probably my inability to handle the heat. I know archers who use wood core here and have no problem, despite the extreme heat and strong sun.


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## blue_ridge (Mar 20, 2008)

I think the biggest issues are cost of manufacturing and quality. Regarding wood, it takes skilled labor to create well made wood cores, whereas foam does not. So foam core is cheaper to make. Just speculation, but maybe this is why Hoyt, W&W and Samick market hype the foam cores so much.

Also, foam is a generic term. So I would not assume that any foam core is better than any wood core. Border believes their wood core is without peer. But they developed their own proprietary "hyperflex" synthetic core, which they say is NOT foam, but is significantly more stable and faster than any other limb core made. 

I imagine some of the old Sky limbs shot by U.S. Olympic archers (even in 08!) were probably absolute top quality wood cores that deliver very repeatable, consistent performance. But do "the big three" really want to continue to pay higher mfg costs for top wood core limbs? Might be niche here for a smaller, more specialized company to enter the scene with top performance limbs.


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## Vittorio (Jul 17, 2003)

Wood, foam or syntetic core. "The big three" as you call them are still producing limbs with both kind of cores, and Samick has also combined them in the Extreme BF limbs. As far as I understand, there is no real cost difference becasue of the core used, but other materials are more influencing said cost than core material. So, is the final combination of the different layers used to make the limbs that makes the cost, and basically the core is just one of these layers. But, in the recent years, market has started to consider "foam" related to top level and "wood" related to past. Matter is of course not so simple, as the new offer of dual core choice from W&W new limbs is surely telling.
This debate will last for many other years, for sure.


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## engtee (Oct 2, 2003)

Vittorio,
Has it been your experience that wood core is influenced by temperature and humidity, while foam core is not?


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## Vittorio (Jul 17, 2003)

engtee said:


> Vittorio,
> Has it been your experience that wood core is influenced by temperature and humidity, while foam core is not?


Basically the answer is opposite. As modern limbs are almost perfectly sealed from influence of any kind of moisture, the only parameter to be taken in account is ambient temperature. And ambient temperature is surely influencing the flexibility of any material in the limbs layers. 
And layers are made mainly of syntetic materials, while core is just one of them. Pls remember that the core in the limb only has a purpose of spacing the front and inner face, thus determining the poundage. But, as it flexis and moves toghether with the limbs, while being thicker than any other layer, its properties against temperature are much more influencing the overall performance than the proprties of the external layers. 
In this extent, the wood is a fanatastic material, only equalled but not beaten yet by any syntetic foam, as far as I know. Of course, some limbs manufacturers will tell you that nowdays foam is the best and most stable material, and it may be... propably for some but surely not for all kind of foams.

P.S.
I dream of the day when a limbs manufacturer will state on a tech sheet something like " Operating temperature: -10 to +50 Centigrades +-2% efficiency variation, +-2% torsional stability from suggested 25 Centigrades normal operation" 

P.P.S
The limbs have all to "warm up" before returning to a repeteable state of shooting. It means that limbs taken out from a car bag at -5 will need some shooting to start operating constantly even at the same -5 ambient temperature.


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## Warbow (Apr 18, 2006)

I'm wondering if wood limbs may last longer than foam?

I realize that synthetics can be very durable, but stiff foam just sounds, well, breakable. But, I admit my impression is based on faulty data and visceral experience with foams that are designed to crumble, like the green foam used for holding arrangements of floral decorations in place (that we also use as a wadding for holding in blank charges in muzzle loading guns for theater), and I realize the foam in limbs is designed to be sturdy...


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## BergerButton (Dec 3, 2008)

Warbow said:


> I'm wondering if wood limbs may last longer than foam?
> 
> I realize that synthetics can be very durable, but stiff foam just sounds, well, breakable. But, I admit my impression is based on faulty data and visceral experience with foams that are designed to crumble, like the green foam used for holding arrangements of floral decorations in place (that we also use as a wadding for holding in blank charges in muzzle loading guns for theater), and I realize the foam in limbs is designed to be sturdy...


I love my carbon/foams made by Samick!! The preformed brilliantly this past summer in the mid day sun as well as in the colder months and last winter. What I do is bring my bow square with me to all shoots and several strings that are all shot in and twisted correctly for my set up. During the long shoots I change my string at the 1/2 way point.

The weakest link on any bow related to temperature is always the string. I did the same when there were no carbons in my kit and re tuned at the 1/2 way point in order to keep things tight down range. Heck direct sunlight on a hot day messes up my Hoyt compound bow's accuracy as well but there is no "re tune" available there.


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## engtee (Oct 2, 2003)

Warbow,
Whereas manufacturers expect shooters to get 3-5 years of use out of a set of modern limbs, there are still plenty of Sky wood/carbon/glass limbs, manufactured in the eighties, being used, and the users swear by them. Also plenty of wood core bows, even older than that, still being used. So, I would think that, in general, wood core limbs are longer lasting. Might be the material, might be simply that the adhesion is better.


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## jmvargas (Oct 21, 2004)

i have always used carbon foam limbs since i started 4 years ago(hoyt vectors,M1s,carbon +, samick extremes,pse xpression and winexes) but have now switched to carbon wood(sold ALL my carbon foam limbs) as i was impressed by the smoothness of my pse pro-elites(32#L) which are supposed to be rebranded winacts....i then got another winact(34#L) and now also have a pair of border HEX5-H limbs with the same wt as the winact(34#) on order and will compare the performance of both limbs when it arrives....


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## triode (Feb 11, 2007)

Interesting discussion going on!

I thought the main reason for using foam core was to gain speed compared to the “old” wood core because of the weight difference? Is this difference too small to be considered important?

So why are they “introducing” wood core again? Vittorio mentioned that the wood core are less prone to variations in temperature and probably true (I dont have that knowledge to judge), but that is not what the marketing team wanted us to believe a year ago... Are there more advantages for wood cores compared to foam?

It has also been great to know:
Is it really easier to manufacture straight and consistent limbs with wood core instead of foam?
Is calculated average life for wood core better than foam?
Is poundage changes over time different (aging effects)?

For the professional archer these questions may not be of highest importance because they change limbs more often and can switch if they are not well performing (such as straightness and unstable tiller)... bur for the average archer who dont have money to change them often it might bee.. 

As often product changes are made to please the market and to make them believing they are buying the latest and the greatest product with space age technology added... 
The future is probably foam, but what is the best option today?

In the catalog for 2008 we could read the following (page 12) on wood limbs/foam:
bowsports.com/w&w08.pdf

“in the case of a wood core system the features offer superb tolerance due to the fibers and its high adhesive property. However, it is heavy, weak in humid weather, and due to knots in the fibers causes limbs twists. Contrary to the wood core limbs, synthetic foam cores features lightness and strength against humidity. However it is brittle plus the adhesive property is weak which results in weakness in limb endurance. Kevlar hybrid foam is the new core that has both merits of wood and foam added fibers on the foam. This new material reduces limbs twisting and increases limbs endurance as well as keeping all of the advantages of superb tolerance, high adhesive properties, light and consistency in humidity”

In 2009 we will have a new top of the range wood core limb apecs prime... but are there not any “knots” in the fibers in these, interesting to know how these problems are solved...?


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## Seattlepop (Dec 8, 2003)

Vittorio said:


> P.P.S
> The limbs have all to "warm up" before returning to a repeteable state of shooting. It means that limbs taken out from a car bag at -5 will need some shooting to start operating constantly even at the same -5 ambient temperature.


Vittorio, I'll assume not all limbs have the same warm-up requirements, but if there is a general rule that can be applied it can be significant because not all venues have the same warm-up opportunities. I'm referring to the "Two official warm-up ends" which is very little warm-up (for this archer anyway) and this is especially so if no unofficial warm-up areas or time is provided.

Can you give a general rule regarding the amount of time or number of shots required to warm up the average limb? Also, how much time does it take for a limb to lose its warmed state? For example, if I shoot 25 arrows at home and it takes 30 minutes to get to the venue, am I wasting my time as far as warming up my limbs? I've also wondered about the 1 hour lunch break regarding limb warm-up since no practice ends are allowed when shooting resumes.

Thanks for your time, always greatly appreciated.


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## engtee (Oct 2, 2003)

Added to what Seattlepop has said, I wonder if wood core has less warm-up than foam. Vittorio?


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## drn (Mar 27, 2007)

I have found this to be an oustanding thread because it imparts a lot of insight..

It, however answers few questions and here we are 4 years later...can we add anything that we have learned?


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## Borderbows (Apr 4, 2009)

epoxy is oil based. and the binding agent between the spheres in the foam is epoxy.
Have you seen the price of oil these days.
Its affecting carbon costs, epoxy costs.

Sythetic cores are constant and easy to control compaired to wood cores. so i beleave (without any data to back this one up) that smoke and mirriors about temperature stability of the core was used to create a gap in the market that also suits mass production.
Has anyone done a compairson of air desnisty and temperature causing updrafts on different surfaces as the day goes on, and alikened that to arrow performance.
i dont think its the bow!
For example. we took a bow with 50lbs at 28" and set it outside at -5deg C. (wood core) for 2 hours meausured a DFC, then placed it in an oven at 50deg C, and repeated the DFC. and again. No difference.
So human performance difference and air desnisty make more difference in our view.
(no extra data to back this up than not even a 0.05lbs difference in bow weight between -5degC and 50DegC)


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## imcabby (Sep 28, 2012)

drn said:


> I have found this to be an oustanding thread because it imparts a lot of insight..
> 
> It, however answers few questions and here we are 4 years later...can we add anything that we have learned?


agreed!


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## drn (Mar 27, 2007)

@Borderbows-
Human performance is a no-brainer factor but air density making more of a difference is huge! In that light, one could say that an lite archer could perform with *any* tuned bow/arrow system and the brand, model and components only matter because they are part of this tuned system. Such a system could be mimicked by yet another totally different combination of elements entirely, and so long as this system behaved in a manner that the elite archer could work with the results could theoretically be idential, given identical physical environmental factors. wow.
So, the so-called best limb is one that gives repeatable performance shot after shot...consistancy.


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## Zbone (Aug 4, 2012)

Curious to see this thread resurrect after 4 years and being an old wood/glass guy when they indicated carbon backing and belly, what kind of carbon are they talking? I assume all carbons are not the same?.... How do they compare?


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## RyuKage (Nov 21, 2019)

BergerButton said:


> Warbow said:
> 
> 
> > I'm wondering if wood limbs may last longer than foam?
> ...


When you say the Samick foam limbs (I'm assuming you were talking about the R3 Samick discovery from limbs) do you shoot with those limbs in combination with another riser? Or are you using the Samick Discovery riser


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