Build your own skis!

<br> SkiBuilders.com <br><br>This is one of the most interesting ski websites I've ever seen, even though I have absolutely no desire to build my own skis. It deserves some free advertising. The protagonists include Little Kam, Big Kam, and Kelvin, at least one of whom (Big Kam) is a TAY regular.<br><br>

This is awesome guys!!!!!<br>Did you guys create this site?<br>Your skis are definitely sick.<br>I still would like to drop by sometime and check out the operation.<br>When I lived in Utah and worked for quality Composites, we made a bunch of fatties with carbon fiber and kevlar.<br>Most of them actually came out ok.<br><br>Keep on buildin'<br><br>Bryan Curtis\ Wasatch Bry<br>

That's awesome! I want to try some of those water skis on a powder day or on a deeeeep corn snow day I wonder how a ski with zero side cut would work? A Heavier ski? A more flexible one? This sounds like too much fun. I'll have to try this one day...

Great site Kam. When are you going to start working on the splitboards?

hey, that was suppose to be a secret &lt;wink, wink&gt; !! (Amar, i slipped a little something into your PayPal account. ;D)<br><br>what can we say. we love to ski! and it naturally lead to making skis in the garage. the three of us built the site to document the fun we're having, and, of course, to share information. ( note to self: a 5" diameter firehose with 60 psi of air can do a lot of damage!...ouch, my eye!). anyway, most of the credit goes to my cousin Little Kam (in Tahoe) and Kelvin.<br><br>Jason: Little Kam's Red Oktobers (Shane McConkey Spatula-like skis) with reverse camber and inverse sidecut kick arse!!! they are amazing in soft and deep snow. contrary to popular belief, they turn like no other, and with control. traditional skis (with sidecut where the tip and tail are wider than the waist) have a tendency to catch an edge, or hook, but not the Okts. hell, there's not much of an effect edge to hook. you can really motor on them in the soft. did i mention they turn like no other? oh yeah, so much that you can do a full circle if you pressure them correctly. speaking of pressure, the control is directly underfoot. not along the entire length of the ski like traditional rides. and with proper technique you can vary how the pressure extends from cord-center. you have to try them. fun, fun, and it's currently my powder ski of choice!<br><br>there are a few cons though. they fear the hard pack. well, not really turning-wise, but there's not much control (but that's relative). they don't traverse very well either, but then again, we kind of went a bit overboard designing the Okts, e.g., the inverse sidecut is generous: 135-145-125mm.<br><br>we're working on a new pair that is a hybrid, one edge with zero sidecut for more control and one edge with a dash of inverse sidecut for that cool squirrely feel. my hunch is that it will be a kick arse backcountry ski, for the variable conditions and what not. i might end up in the hospital skiing these things, but here's a sketch anyway:<br> <br><br>the DOINKs will be made in two sizes to test: waist = ~110mm-ish and waist = 200mm-ish, and we'll vary the length "l".<br><br>speaking of ski designs, does anyone have any thoughts about a good backcountry ski design?? i have no idea.<br><br>jimjar: splitboards: yes. but only after we finish our SplitMono, designed for the backcountry, of course. ;D

A good backcountry ski is fat and light. Maybe you could make air channels e.g. Tua Helium, or use lower density wood species. <br><br>What bindings are you using on the fatties? How much does it cost in materials to make a pair? <br><br>What you're doing is definitely cool.

A good backcountry ski is fat and light. Maybe you could make air channels e.g. Tua Helium, or use lower density wood species.

<br>zenom -- i agree: fat and light. surprisingly, our homemade contraptions are fairly light, even for their width. materials such as wood, standard p-tex, metal edges, fiberglass and epoxy are relatively light. maple is hard and relatively dense, but mixing poplar makes the skis lighter. but, when we start using metal (such as Titanal) the skis may weigh more.<br><br>

What bindings are you using on the fatties? How much does it cost in materials to make a pair?

<br>the bindings we're using include: Hammer Heads, G3 Targa with stiff and ridiculously stiff springs, Black Diamond O2 and Black Diamond 03.<br><br>the cost of materials is estimated between $100-$130 per pair. the estimate doesn't include metal or exotic layers, for example, Kevlar.<br>

what can we say. we love to ski! and it naturally lead to making skis in the garage.

<br><br>Haha, this is a classic line. Natural for a couple of engineers maybe. Great site guys!

The core doesn't need to be much, that's why many skis use foam. I prefer wood core. The ski stiffness comes mostly from what's surrounding the core. If I were making a ski, I'd router or kerf the wood core to remove mass where it's not needed. Poplar has a higher MOE/SG (modulus of elasticity/specific gravity) ratio than maple (2.95). From a quick look, it appears that port orford cedar, silver fir, or noble fir (4.41!) have an even better MOE/SG ratio than Poplar. I'd be happy to give you more technical info if you want. <br><br>Regarding the bindings, do you see much difference between a beefier binding on a fat ski like the Hammer Head, or a G3?

The core doesn't need to be much, that's why many skis use foam.

<br>actually, i've found that the core does make a big difference. (i'm not sure what kind of foam is used for skis, but it probably has similar properties as wood. isn't foam cheaper? rumors say it breaks down faster than wood.) anyway, i think the majority of a ski's flex is determined by its core; the flex depends greatly on the dimensions of the core and its profile. this is probably the case because the layers of fiberglass that we use (2 layers) is relatively thin.<br><br>

I prefer wood core.

<br>i like wood too. wood has a very nice feel. i think i like it because it is damp, but at the same time, snappy.<br><br>

The ski stiffness comes mostly from what's surrounding the core. If I were making a ski, I'd router or kerf the wood core to remove mass where it's not needed.

<br>an interesting topic. i don't know the answer. the only thing that sticks out in my mind is the following: the natural frequency wn of a simple spring-mass system is:<br><br> wn = sqrt(k/m); where k = spring constant and m = mass.<br><br>seems like there are two parameters to play with. for me, a light ski (small m) doesn't feel very solid, like it chatters and vibrates a lot, especially in hard and variable conditions, at high speed. this makes sense as small m makes wn large.<br><br>

Poplar has a higher MOE/SG (modulus of elasticity/specific gravity) ratio than maple (2.95). From a quick look, it appears that port orford cedar, silver fir, or noble fir (4.41!) have an even better MOE/SG ratio than Poplar. I'd be happy to give you more technical info if you want.

<br>i'm not familiar with MOE/SG ratio. what does it mean, exactly?<br><br>

Regarding the bindings, do you see much difference between a beefier binding on a fat ski like the Hammer Head, or a G3?

<br>i feel that a beefer binding helps to drive a fatter ski. stiff boots help too.<br>

The original powder specilists at ALta took thier wooden skis and had them planed to a wisp.<br>Dolores Lachapelle : <br> from <br> "Deep Powder Snow: Forty-Years of Ecstatic Skiing, Avalanches, and Earth Wisdom" <br>by Dolores Lachapelle (Paperback - June 1, 1993) <br><br>I'm of the opinion that in true powder, edges and side cut are not that important.Fat and soft flex is what I like. <br>cool site !<br>

Kam,<br><br>MOE/SG. Pull out your Mechanics of Materials texts for a more technical answer, but here's my TAY answer.<br><br>MOE = the slope of a stress strain curve in the elastic region. Could be thought of as stiffness.<br><br>SG = specific gravity. It is density relative to water. So if your SG is 1.0 you'd be suspended in water and weigh 62.4 pounds per cubic foot. Could be thought of as mass.<br><br>Basically, I was showing which wood species have high stiffness but low weight. (Actual composite, or peice of material, stiffness is function of material MOE and geometry. Geometry is very influential.) You were considering the same and noting that is the natural frequency, wn. I'm not sure I concur with your wn assesment and effect on ski performance. I have very light pair of Tua Titans, which are pretty stiff (wood core with air channels, but with titanal at top and bottom). I have never had these chatter, and they'll bust through crud at high speed. I attribute their good performance to high bending stiffness and high torsional stiffness. They're great for backcountry because they're light. I've had crappy Black Diamond foam core skis chatter like crazy - they weren't very stiff either.<br><br>My comments about the core not needing to be much are based on the moment of inertia and whatever it's torsional equivalent is called. Again, pull out your Mechanics of Materials text. The materials that contribute most to bending and torsional stiffness are those located furtherest from the cross sectional centriod. These concepts are real and used in design of structural elements, including skis. You don't often see a layer of titanal used at the ski neutral axis. Engineered wood products are the same. The best laminates are placed furthest from the core. The worst are placed at core (nuetral axis) - to achieve highest strength and stiffness of the composite. <br><br>My profession is as structural engineer. My expertise is wood, engineed wood products, and even FRP-wood composites (carbon, aramid, fiberglass). I could go on and on but won't for hopefully obvious reasons. I have a lot ideas about ski design, and can even get you very select wood veneers if needed. Hopefully we'll talk more in person or email sometime. <br><br>Robie brings up another good idea. How about just laminating select thin wood veneers. If it wasn't torsionally stiff enough then add oriented fiberglass. <br><br>A final note. I notice the Bro model uses a layer of rubber as one of the laminates. Interesting. Lot's to try and ski...<br><br><br><br>

<br>we're working on a new pair that is a hybrid, one edge with zero sidecut for more control and one edge with a dash of inverse sidecut for that cool squirrely feel. my hunch is that it will be a kick arse backcountry ski, for the variable conditions and what not. i might end up in the hospital skiing these things, but here's a sketch anyway:<br><br>the DOINKs will be made in two sizes to test: waist = ~110mm-ish and waist = 200mm-ish, and we'll vary the length "l".<br>

<br>Sweet! So as you're turning both skis in pow, one ski will try to hook, while the other will Spatulate! <br><br> <br><br>Just kidding! Curious idea, I'm looking forward to the test results.<br><br>As for backcountry skis, a good backcountry ski is defined as a good alpine ski with Dynafits. ;D

hey zenom:<br>

<br>My profession is as structural engineer. My expertise is wood, engineed wood products, and even FRP-wood composites (carbon, aramid, fiberglass). I could go on and on but won't for hopefully obvious reasons. I have a lot ideas about ski design, and can even get you very select wood veneers if needed. Hopefully we'll talk more in person or email sometime. <br>

<br>oops, i didn't mean to come across as doubting your expertise. in fact, it's great to get input from such a knowledgeable person. i'd like to hear more about your ideas. we're going to try wood veneers, for the topsheet. <br><br>

<br>I have very light pair of Tua Titans, which are pretty stiff (wood core with air channels, but with titanal at top and bottom). I have never had these chatter, and they'll bust through crud at high speed. I attribute their good performance to high bending stiffness and high torsional stiffness.

<br>i think that high torsional stiffness is good for a ski. but do you think that high bending stiffness gives good performance? i'm not sure. i wish i knew.<br><br>Paul: yes, "Spatulate"! i like that!!! ;D btw, do you want to take them out for their first ride?<br>

I would be honored!

Kam, I was just trying to let you know my background so you knew where I was coming from. I didn't take your comments as doubting what I was saying. I've never built any ski's so you're way ahead of me anyway.<br><br>As for ski stiffness, I think it depends on several factors. Mostly though, skier preference. I haven't skied enough different skis to really know. I have fat soft pair that I like and skinnier stiff pair that I like too. For me it depends on conditions, how soft is the snow.<br><br>

Kam-<br><br>I stumbled across your skibuilders site a couple months ago, and I have to say it is VERY well done. Practically a how to book. Thanks for the info, and keep up the good work! I'm sure all the big ski companies will bankroll you guys as designers soon enough <br><br>Larry- you might check out a super light pair of aluminum crampons pair'ed with some firn skis. There are several models out there with crampon-like step in bindings.

<br>As for ski stiffness, I think it depends on several factors. Mostly though, skier preference. I haven't skied enough different skis to really know. I have fat soft pair that I like and skinnier stiff pair that I like too. For me it depends on conditions, how soft is the snow.<br>

<br>hey zenom, it would be nice to chat and get your input! i agree that skier preference is important, definitely. though my gut tells me that a ski's dynamic response may be a factor, it's probably more complicated than that. now didn't K2 play around with this in their piezo-based designs? i heard HEAD also focused some of their attention on this too. John Howe published a book about the physics of skiing. it's sitting on my desk and i haven't read it carefully yet. anyway, i'm not quite sure what makes a ski feel good, so i'll have to do more research and think about it more. i'll be the first to admit that i'm clueless. but for now it's pretty fun to build whatever and play around with different designs.<br><br>i'm open to ideas, so let's hear it from the community. what skis do you like and why? cough it up!<br><br>

<br> Just a crazy idea for Kam:<br>This is something I have been meaning to work on but haven't got around to it. A superlight pair of shorties that would fit on to crampons for use on summer snow. The crampon would serve as the binding with the points fitting into appropriate slots in the shorties, which might be just 1 1/2 to 2 feet long. Light enough so you wouldn't mind carrying them while backpacking. Instead of boot skiing down suitable slopes, you would pop these on to your crampons, fasten with some sort of strap, and .... who knows! <br>Larry

<br>Larry: i say we build them!<br><br>

<br>...I'm sure all the big ski companies will bankroll you guys as designers soon enough <br>

<br>a big mistake. the only thing i'm going to do with their money is go skiing with it! ;D

<br><br>i'm open to ideas, so let's hear it from the community.  what skis do you like and why?  cough it up!

<br><br>Volkl G4...stiffness of a 2x4 and some sidecut makes for a sweet, super solid carve for a guy like me who over works the power factor needed to generate a turn. They'll also blow through anything with ease, and will float the mank due to their wide dimensions. In a nutshell, stiff flex, short, fat dimensions with some sidecut.<br><br>Backcountry downfall of the G4...they weigh a ton.<br><br>One hair-ball coughed up!<br>

thanks JibberD for your input! i've skied the G4s. i like them and they do plow! do you think it's the weight that makes them plow?

I have a pair of Atomic VARS mid fat with rental bindings and related to The old heli guides. These babies are heavy and do they ever bust through anything. weight is definetly the answer for skied out crud and mank.<br>Tandem tele with two skiers on one pair of 210cm is the answer for plowing furrows through anything. Empirical knowledge!<br>Robie<br>Docterate in Empirical studies

thanks JibberD for your input!  i've skied the G4s. i like them and they do plow!  do you think it's the weight that makes them plow?

<br><br>I'm not a scientist and I don't play one on TV... But I think it's mainly the stiffness of the skis that make them plow so well. I figure it's my girth combined with the force of gravity that is providing the plowing force. The ski (also boots and bindings) it seems, has to transmit my body weight and pressuring forces to the snow. I just think a stiffer ski does this more efficiently than a soft ski.<br><br>I would guess that the weight of the ski does play a small roll in plowing in that it may help cut down on ski deflection when it's unweighted. But again, I'm no scientist.<br><br>It seems to me, the holy grail of ski performance ski designers is to come up with a solid ski that doesn't weigh a ton. I look at the Atomic Beta series as an example of this approach.<br>

<br>... I figure it's my girth combined with the force of gravity that is providing the plowing force.  The ski (also boots and bindings) it seems, has to transmit my body weight and pressuring forces to the snow.  I just think a stiffer ski does this more efficiently than a soft ski.<br>

<br>interesting, and worth noting. also, considering my light-boyish weight, it brings to mind the classic collision problem between a VW Bug and an 18-wheeler. for me i guess a stiff and light ski is more effective at tossing me around in the crud. but who knows. it's probably more operator error than anything.<br><br>i wonder if there's some way to predict performance (e.g., crud busting power) in terms of skier's weight, ski stiffness and weight, density of snow and speed? but then again, i'm probably making this way toooooooo complicated.

Hey Kam - <br><br>You've got a wonderful site and you're doing some excellent work - Thanks. We met earlier in the year at Proski in Seattle when I was picking up some skins. I'm a Mechanical Engineer as well(and part time alpental ski patroler, very part time this year ) but feel my limited ski knowledge has come about mostly from experience.<br><br>I tend to like skis that are a bit softer and more forgiving, especially the tails - I'd rather push the skis around than have them "talk back". I think a slightly stiffer shovel and softer tail helps a ski do well in all sorts of soft snow - the softer tail sinks and kind of helps the shovelsplane without folding like a soft shoveled ski will. Lots of snowboards use this concept and it works well there too.<br><br>That said alot of my friends like the solid platform and feel of a much stiffer ski - but i think they tend to be a bit heavier than me. Also a stiffer ski might be better if you go shorter in length?<br><br>I also like a little more weight in the ski for lift skiing in variable snow but really don't like it for touring - so I personally would sacrifice the cadillac feel of a heavier ski if I'm skinning any significant amount.<br><br>