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The truth about Wood/Foam/Synthetic Cores? - Page 2

post #31 of 51
I can tell you one thing. As a person who has worked 30 plus years with wood, no matter what kind of wood it is, flexing and unflexing wood over a period of time will break down the fibers and cells and it will fatigue. They might have more snap, rebound and life when new but they will break down. I'd bet there is a bigger drop off in ski performance in a wood ski that a foam or synthetic core ski. As stated, wood cores have more feedback than dense damp core skis. Afteer 100 days, you would notice more performance loss.
post #32 of 51
Thread Starter 
Another thing to remember is that skis vary from pair to pair, particularly with wood cores. Go into a shop, or multiple shops and flex the same pairs of skis in the same length. If you can go from one to another, a lot of the time you can feel a difference in flex and feel. Also, most good skiiers can tell the difference between wood and foam, many of them by simply hitting the tails against the ground. wood has a very particular resonance. wood core skis definetly have a much more springy, poppy feel to them as well
post #33 of 51
Synthetics in my Rotors, no way man!!! Ah I will have to send them back. - they certainly do not lack edge hold, torsional rigidity/ stability or energy and I am certain that I am going to get over 200 quality days on them.

Actually I heard that the synthetic core is a lay up of wood/ foam/ other synthetic stuff - as someone wisely observed above it is the synergy of the materials used to achieve an overall feel and precision.

Stockli for example have the edge on quality control because they are making 40000 skis in a state of the art factory in Switzerland, with all the QA and enviro laws that they have to meet in that very ordered country. This kind of precision also contributes to higher per unit costs which most people are not willing to pay and will never appreciate as value for money unless they are lucky enough to ski on a pair.

We have also gone into three seperate threads with the introduction of race stock. Completely different arguement. Race stock are made to be hand tuned, skied by experts and not expected to be used for more than two seasons (ie one as race ski, one as training ski) at the most. they are also expected to be used as race skis ie training or racing on a groomed race course.

Also mostly when someone is refering to a 'foam' core they are probably talking about a cap construction ski as well. IMLE sandwich construction skis tend to be higher quality than cap skis anyway so will have a superior core, regardless of material used. Even the big manufacturers remain commited to sandwich construction/ laminate skis for their serious high end skis (read race stock).

Laser SL - I cannot see anyone complaining that the synthetic core lacks pop or that it lacks edge hold/ torsional stiffness. Difference between FIS and consumer - one is designed to be hand tuned and used on a race course, the other is for consumer use ie shop/ machine tune and skied all over the mountain. Is there a big difference? I do not know I have not skied the FIS stock and am probably not good enough to tell the difference between FIS and consumer stock anyway.

Finally one has to consider what the skier wants and most intermediate skiers are not going to want a ski that is as heavy as my skis (or any well made sandwich construction ski). A comment heard from most people who lift them or hold them for me (admittedly the plate and metal binding contribute to the weight). The fact that they will wipe most other skis in their category when skied is something that is lost on most people. I think that Head has recognised this hence the new hollow tech or whatever they are calling it fibreglass in an attempt to still build a good ski (Im78/82/88, Supershapes) but keep the weight down.

Hence the popularity of PRs with plastic bindings or other such mass produced creations on the slopes.
post #34 of 51
Thread Starter 
heres another anecdote...volkl explosivs....pretty amazing skis. stiff as ****, springy, wood core, awesome ski. ive owned two pairs, both the marronish-brownish-reddish-pinkish-purplish color in a 165. My first pair, that i skiied for 2 seasons and then for rock skis, are definetly noticably softer. however..when i say 2 seasons plus rock ski time, im talking..around 225 days on them total. even the most durable skis gradually wear down and become less stiff...
post #35 of 51
The ski industry runs on old wives' tale. Preconceived notions about core materials are one of the tired old standbys.
Quote:
Originally Posted by Richie-Rich
Actually the current Corvette, the best Corvette made thus far, uses a wooden floor! Similar construction as a ski, reason being GM engineers said they were unable to find any man made materials that exhibited all the traits that only wood had. Believe it or not.
Translation: Balsa is light and cheap, and nothing else is better at the same (or even broadly similar) cost. Boats use(d) balsa cores for the same reason: cost.
Quote:
Originally Posted by Cirquerider
If the skiers perception remains that wood cores are superior, that perception will become reality. If skiers won't buy synthetics in the upper tier of skis, they will become associated with lower level (intermediate and rental fleet) skis.
The man speaks truth.

I've owned many pairs of metal/foam core race skis that didn't suck. In fact, though they weren't the most fun skis on earth, I was always a more consistent skier on them. My favorite race skis ever were wood/metal/snappy as heck Blizzards. Skied out of courses like it was my job.
Quote:
Originally Posted by bennelur
Go into a shop, or multiple shops and flex the same pairs of skis in the same length. If you can go from one to another, a lot of the time you can feel a difference in flex and feel.
This is called poor quality control. Or at least it would be in any other industry on earth.
Quote:
Originally Posted by Lars
I'd bet there is a bigger drop off in ski performance in a wood ski that a foam or synthetic core ski.
At my own peril, I will guess that the failure/degradation of the adhesives between layers in the laminate from shear will have a bigger impact on performance than changes in the core material...wood/plastic/cardboard/whatever. I make this guess because I too have cut apart skis where resins failed, and because my extremely limited knowledge of wood fatigue suggests that we will see delamination or fracture before we see a significant change in mechanical properties.

If foam core skis are less likely to suffer greatly there, I would guess that is correlated to the fact that only a few serious manufacturers with real engineering teams build high end foam skis...ergo they have a better chance of getting resins and processes right than the cottage industry types.
Quote:
Originally Posted by bennelur
even the most durable skis gradually wear down and become less stiff...
Probably true given that skis tend to get abused in many ways. A well designed ski rocking the groomers should last more or less until you wear the base and edges off it with little change in performance. Its the jumping (well, more specifically the landing and crashing) plus the bumps, tip rolls, etc. that kill skis.
post #36 of 51
Thread Starter 
While I agree with skiing man that there definitely is a lack of quality control in the ski industry, its going to be impossible to make 2 wood core skis flex exactly the same. Thats why its so important to buy the skis in a pair, and more expensive skis are always matched. They do this because the wood they use for both skis is from the same part of the same tree, so it should have a similar flex. Two different pieces of wood, even if they are from the same species of tree, may have very different flexes. This can result from the size/age of the tree, if there were knots in the wood, or a thousand other factors. So i think wood core can have a lot of variations and therefroe could be called inconsistent, but then again, foam coulld be consistently bad too. (see pocket rockets)
post #37 of 51
Please consider that if one were not a downhill racer, hardcore, etc. that foam core skis can be a great value for us average rec skiers. However, I love the construction/weight of my friend's wood core/triax wrap K2 Phat Luvs.

One just needs to demo to get the right feel, period. My big old pr's... still going strong.. and I do beat them to death. Maybe the titanium sheet helps.

I love watching the extreme skiers on the Warren Miller films trying to figure out what skis they are using. And ... I think it is more about the skier than the ski. But, certainly you have seen those pr's flash across the screen. Why would these top skiers use anything but wood core?

... a little off topic, but it would be interesting to make a list of ski credits from these films. They can afford anything they want. Even so, I am not doing 70 down an Alaskan cliff like they are.

Nevertheless, skiing is changing with more folks interested in off piste skiing... I think that calls for a softer ski. So, stiffness isn't everything.

I have read somewhere that it is the cap construction that counts and wood or foam is just filler... foam is more consistant in construction than wood and of course cheaper.
post #38 of 51
Quote:
Originally Posted by Ruxpercnd View Post
But, certainly you have seen those pr's flash across the screen. Why would these top skiers use anything but wood core?
Topsheets do not a ski make. If you want to sell ski A, you print ski A on top of the skis your sponsored athletes are skiing on. Athletes being athletes, what they are skiing on will vary quite wildly. This is true in racing, freeskiing, etc.
Quote:
I have read somewhere that it is the cap construction that counts and wood or foam is just filler... foam is more consistant in construction than wood and of course cheaper.
Try not to believe everything you read. A true monocoque ski (what you have implied you've read to be the case) is never going to be very good/profitable/durable, because mechanical properties don't change with scale and skis are thin. Also skis need immense buckling strength and stressed skins suck at that without a core to withstand the compression loads. The core will always remain important in high quality skis.

Foam ski construction on a grand scale is about costs for sure, but it would be unwise to assume that plastic cores are necessarily cheaper or worse. Companies like Rossignol have turned out vast numbers of low cost wood skis that suck compared to their high end foam skis, and of course the opposite example exists as well. If I had to choose a cheap wood ski or a cheap foam ski, I'd choose a cheap wood ski. It isn't possible to make such generic statements about high end gear.
post #39 of 51
Quote:
Originally Posted by Ruxpercnd View Post
Please consider that if one were not a downhill racer, hardcore, etc. that foam core skis can be a great value for us average rec skiers. However, I love the construction/weight of my friend's wood core/triax wrap K2 Phat Luvs.

One just needs to demo to get the right feel, period. My big old pr's... still going strong.. and I do beat them to death. Maybe the titanium sheet helps.

I love watching the extreme skiers on the Warren Miller films trying to figure out what skis they are using. And ... I think it is more about the skier than the ski. But, certainly you have seen those pr's flash across the screen. Why would these top skiers use anything but wood core?

... a little off topic, but it would be interesting to make a list of ski credits from these films. They can afford anything they want. Even so, I am not doing 70 down an Alaskan cliff like they are.

Nevertheless, skiing is changing with more folks interested in off piste skiing... I think that calls for a softer ski. So, stiffness isn't everything.

I have read somewhere that it is the cap construction that counts and wood or foam is just filler... foam is more consistant in construction than wood and of course cheaper.
The pros do not get to ski on anything they want to. The sponsors give a pro a ski, and tell him to make it look good. Thats why they're the pros. Sometimes they get to ski some super secret team only ski, that has the same graphics as retails skis, so that in pictures, it looks as if they're skiing normal skis.

And theres nothing wrong with pocket rockets, a lot of people like them. I only mentioned them earlier because they are indicitave of the "typical" foam flex.
post #40 of 51
Anyone remember the original fiberglass composite skis? Basically a wood ski with an epoxy coating. That said, by the time we got there, skis had evolved from solid wood to laminated strips of wood which were much stronger and had better flex characteristics.

Early Kastle skis used to advertise the elaborate directionally laminated wood cores. Volkl raised and milled their own trees for their famous wood cores. No ski manufacturer elaborates on the contents or construction of their core any more. Could it be that the mass-produced wood laminate blanks being used are just inferior? Probably. OTOH, progress in composite materials, resins and reinforcement strands has become the foundation of engineering longitudinal flex and torsional rigidity that was not possible with previous generation materials and presses. This has made wide and highly shaped skis possible. While wood cores are still prevalent in high end skis, my guess is that synthetics will eventually take over because of their cost, and capability to be engineered to consistent specifications.
post #41 of 51
Wonder about one statement Cirque makes. Could he or someone else explain why laminated strips of wood are stronger and have better flex characteristics than solid? Just don't know the engineering.

Curious cuz Ogasakas have quite a niche, at least in Japan, created by using solid wood cores. My impression was that a solid wood core is actually stronger (no probs with adhesives between strips, and more homogeneous if selected/cured carefully), but more expensive (lot of rejects, longer curing). Which is why (they say) O's are so light but stable.

Flex, hard to say IMO, since yes you can use different kinds of woods in a laminate (bamboo at tip and tail, or soft underneath or whatever), but OTOH isn't flex more a) about milling to a shape, and b) where the glass goes? I'd guess it costs more to laminate and then mill, than to mill a solid core. :
post #42 of 51
Beyond, All wood has flaws in it irregularities in the grain, knots etc... these are weak points. When you cut the wood into strips and laminate the wood back together in a different pattern it brakes up the weak points and provides a more consistent flex.
post #43 of 51
"Topsheets do not a ski make. If you want to sell ski A, you print ski A on top of the skis your sponsored athletes are skiing on. Athletes being athletes, what they are skiing on will vary quite wildly. This is true in racing, freeskiing, etc."

Interesting comment.

I actually had a racing buddy divulge to me the he was aware of some pros who skied on AK skis but they actually had "paid" topsheets advertising other brands (i.e. an AK ski with a Head/Rossi/Fischer/Atomic/Elan topsheet). That kind of sucks to me as the perceived notion would be that the racer was excelling on one kind of ski when in actuality they were excelling on another (talent of skier not withstanding).
post #44 of 51
There's a guy over on skibuilders who made a ski out of wood salvaged from used pallets. Apparently it skis just fine.

From what I understand, the core provides very little in the way of stiffness to a ski. Mostly it's there to keep the fiberglass layers in shape. It also provides some degree of damping.

Also from what I understand, skiingman is right: degradation is a result of the layers of the ski delaminating from each other internally due to repeated flexion over time. Slamming into moguls is pretty hard on a ski.

This might further suggest that metal in a ski is likely to decrease its lifespan, since it's really hard to get epoxy/fiberglass/carbon/kevlar to stick to each other. (Volant's famous delaminating topsheets support this theory.) Also, this suggests that the less layers there are in a ski, the longer it is likely to last. But mainly it suggests that materials choice (good adhesives) and quality control in the pressing process (even heat and pressure, sufficient cure times, etc.) are the most important variables. Of course, these are just theories.
post #45 of 51
Makes sense Tromano. Thanks.
post #46 of 51
Quote:
Originally Posted by epic View Post
Besides, I love my PRs. I don't care what theyre made of.
I thought they were made of noodles.
post #47 of 51
Thread Starter 
HAHAHAHHA
nice volantaddict
post #48 of 51
Maybe I'll try skiing a lasagna this year.
post #49 of 51
Quote:
Originally Posted by Cirquerider View Post
No ski manufacturer elaborates on the contents or construction of their core any more.
When I stopped selling skis last year, there were still at least two manufacturers who distributed cross sections to hang on the wall and show customers. That is putting the money where the mouth is compared to the often BS explanations you'll find in product literature.
Quote:
Could it be that the mass-produced wood laminate blanks being used are just inferior? Probably.
Not my experience. Companies like Fischer produce skis at a fair price with very consistent and carefully machined and laminated cores. I do often wonder how they can do it at the price points they do it at, with European labor, and stay in business. I think you were right the first time...if skiers desire wood cores, manufacturers will make it happen...though the points you make leading to foams are compelling.
Quote:
Originally Posted by beyond View Post
Could he or someone else explain why laminated strips of wood are stronger and have better flex characteristics than solid? Just don't know the engineering.
(this explanation is meant for someone who knows less about this than you, but I figured what the hey, might as well try and cover the basics.)

Materials like metals tend to be largely isotropic. That is, they have the same strengths and weaknesses (mechanical properties) in any direction.

Fiberglass, kevlar, and other composite fabrics are anisotropic. The mechanical properties depend on how you weave the fiber, at what angles, and so on. Chopped mat can closely resemble isotropy, and unidirectional roving (think of a fiber wound tank, pole, etc) has practically all its strength in one direction. These differences are why we hear manufacturers make a big deal about biax, triax, etc.

Wood is an orthotropic material, so its properties can be described separately in three perpendicular axes. So the strength of wood depends on how the grain is oriented. In skis, quality wood cores are usually what is called vertically laminated. This means that many carefully selected wood strips are laminated and we cut slices off it for our thin/wide cores. The resulting core has more torsional stiffness (edge grip) than a single piece of wood laid flat would. The manufacturer can laminate alternating species/densities/strengths of wood to create a stiffer/softer core, and they can even do fancier things like change the species at different places along the length of the ski for different flexes, or mill out portions of the core to reduce weight. The downside to all this is that the wood must be of extremely high quality, the processes must be very good, and there is a lot of labor involved.

As to monoblock wood cores: they certainly have a place, but they aren't my cuppa tea.
Quote:
Originally Posted by spatters View Post
From what I understand, the core provides very little in the way of stiffness to a ski. Mostly it's there to keep the fiberglass layers in shape. It also provides some degree of damping.
This could be anywhere from completely true to completely false depending on the design. Most wood core skis lean towards the false end of that spectrum. Cheap, cheap foam core skis lean towards the true end. At the very minimum the core prevents the cap/base from buckling by taking on a compressive load...think kids foam ski. OTOH, a good wood ski core can be fairly substantial/stiff even before you put a layer of metal on the top and bottom and wrap it in glass.

I think your theories about durability are spot on. Metal skis definitely delaminate/bend/fail more often than similar skis without metal in practice...
post #50 of 51
I sell only Wood core with a couple of exceptions for superlite touring. It's our preferance and given that waell sell alot of skis, our clients seem to understand the benifits of wood ores skis. There are no realy bad skis out there, just some better than others and these seem to be the woodcore Sandwich construction models. Although i can understand the benifits of; Moncoque injection, Synthetic Sandwich, Wood Cap and Wood sandwich here in Cham' the skiiers smash everything to bits. Since following our protocol o; Woodcore skis, our returns are down to practically zero, last year the only skis returned were Rossi B3 Respect. I'm happy with this, so are the staff and more importantly, our clients.
I skied Atomic Nomad Crimson all last winter and loved it, will i sell it? No, rules are rules.
I'm yet to see de cambered modern woodcore skies, Synthetic models bits and bobs. This shouldn't stop anyone buying Synthetic skis, however the two biggest manufacturers/brands of Synthetic skis are soon to be moving back to woodcore. It speeks volumes to me. My feelings only guys, i also prefer soccer to rugby, beer to wine and women to men, we make our choices. I hope you are satisfied with whatever you buy, my piers here on our selection commitee felt i was being a little too blinkered and radical, 3 years ago, the have since seen the light. Thumb screws have since been put away.
Steve.
post #51 of 51
Cores are just a base to layup other materials on to. A skis flex and feel is a result of all the material combined, not one material by itself. Foam cores are use because of the cost advantages. Most companies using wood cores are using them just to say that are, their quality of wood does not improve the skis properties to a degree that would be noticed. Their are a few types of wood that really have some advantages because of weight and flex but most are expensive when compaired to the woods typically used. The material use to build a ski cost the manufacturer around $40-$80. Some of the better types wood cores cost almost half that. Many time when wood and foam are use together it is because they need a spacer in the ski for added height in the foot area. Alot of cool info is on skibuilder website.
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