Homemade ski at 41 off

[Skihack]

Thought this would be newsworthy even though it is a class c tourney. Open Men's skier Adam Caldwell ran into 41 off at a class c tourney in Smithfield, NC this weekend on a ski he made himself with another fellow skier. I believe he ran 2.5 at 39.5 off last weekend at the Little Mountain Record as well on this homemade ski. Seems alike of homemade skis are coming out. Pretty darn good skiing.

[skihart]

Thats awesome.........I would love to hear more details or pics......

[JohnCox]

Here's a shot of Adam from Little Mountain last weekend....the ski is black....top and bottom.

[Skihack]

I was told Andy Mapple worked with him on designing and building the ski. Second hand.

[bbirlew]

I'd love to ride my own ski one day. I consider myself pretty good with tools/wood/foam/epoxy/carbon fibre after building a few kayaks. Anyone have a how-to on how these guys are building them? Construction methods, etc?

 

I was planning to make a surfboard or wakesurf board as my next project, but I had no idea you could make such a high performance ski as a DIY!

 

[Horton]

My sources tell me: That is not a from scratch homemade ski. Caldwell started with a production ski and reshaped it, changed it and made it his own. This is how a lot of ski dev is done.

[rq0013]

Ive been building carbon trick skis, I use vacum bag process. I want to try a slalom ski next

[Than_Bogan]

Did Adam ski in New England a year or so ago? Feel like I briefly met him. If memory serves he was strong as an ox.

 

I currently know very little about designing or making skis, but I am vaguely considering getting into it someday, maybe even just as a volunteer after I retire.

[SkiJay]

Clearly, this arrow belongs to a good Indian. That's some nice skiing in @JohnCox's photo!

[estrom]

Question...are there any established design or spec restrictions/parameters on ski design? Just something I had never considered. Golf clubs, for example, need to be within certaing specs to be legal for tournament use. Are there any material restrictions, weight, size, ??? specs or can you just show up at a tournament and use whatever you want?

 

[ForrestGump]

You could show up with a 2x6 and rope bindings if you wanted.

[clemsondave]

@horton is correct. Heavily modified ski. I was there this weekend. Dude's an animal! It was pretty windy too.

 

FYI, the legend Tommy Harrington was driving that set.

[estrom]

@shaneh - thanks. That's what I thought.

 

[Bdecker]

@ Than- Adam was skiing in the INT events and the occasional class C in New England for several years before he relocated. Many years ago I saw him crash, tumble-turn up and ski away, so I'd say he has a unique level of strength and ability. Great to see that he is skiing so well.

[jipster43]

Does anyone know which ski he started with?

[eleeski]

Very cool! I'm not sure any ski I build will get me to 41off. But I certainly won't get there on a factory ski!

 

The technology is really not that difficult. Vacuum bagging should work and it is not particularly expensive or tricky. I use an air pressure bladder - very low tech. Advanced materials are readily available. Ski construction is not magic.

 

Getting the ski to perform well IS magic. There are so many variables that radically change a ski's performance - and those are just fin settings! Rocker, shape, weight, edge design and flex are just a few of the big factors. Add in the little things like thickness, the top edge or the shape of the tail can have a huge effect on a ski - bigger than whacking a chunk out of the tail!

 

However, the process can be as fun as the skiing! And when someone like Adam can put both together, wow!

 

@bbirlew and @rq0013 If you get to San Diego, contact me and we'll build a ski under the wing of my plane.

 

Eric

[gregy]

I remembered seeing this on Youtube.

 

http://www.youtube.com/watch?v=5Q0vcRdUgNg&feature=relmfu

[BraceMaker]

@rq0013

 

Are you shaping a core, layering your fibers dry, then bagging and stringing resin? Or are you doing a wet lay up, bagging, and then drawing the vacuum?

 

Benefits of not having to make molds, but it would seem accurate hand shaping of a core would be problematic, having seen guys do surf board cores with belt sanders and lamps, it is pretty impressive when they come out perfectly symmetrical.

[rq0013]

Right now Im shaping a core, layering the carbon and doing a wet layup before vacum bagging. Once you make one and ski on it the ideas start flowing for what you could try.

 

For the next few skis we are going to ty a different shape, different foam core-possibly a hallow ski with carbon stringers, less rocker and different carbon. We had a trick skier whos alot better than me try it without his binding setup and he really liked it.

[BraceMaker]

Interesting, I have never wetted out a fiber lamination prior to vacuum processing. In terms of I do my lamination under vacuum then use a string to distribute the resin evenly and then increase the vacuum to compress the fibers.

 

I need to try some different techniques, but they all sound messier.

[rq0013]

you need to work fast. my first ski i almost didnt get the last layer of carbon and resin down before it started to heat up. Each layer of carbon needs a specific amount of resin. I have a friend who works at Trek bikes and he works with prepreg carbon(similar to Goode) all the time for frames and wheels so he knows alot.

[BraceMaker]

I would wonder if instead of buying prepreg, you could wet out your fibers, roll them in something like a PVA sheet, and toss in a freezer to delay the resin, then lay up so that last layer wasn't working so hot?

 

RQ or E.Lee, willing to share any insider secrets in regards to shaping your first core? Did you start out by looking at a commercial ski, then reduce dimensions across the board by the thickness of your lay up? Or did you just start with making a core and going right to working on your lay ups?

 

Also edge finishing, are your edges ground to shape post lamination? Or how do you get a good clean edge? Just rely on vacuum to draw it around your core? Or pressure into a mold?

[eleeski]

My inspiration was an OBrien Competitor that I split half way down the ski and wedged a 2x4 in the slot to widen the front out. I made a mold from that. That ski worked - barely. So added Bondo to my HO VTX (that I loved) and made a mold from that. That ski rocked! The skis have evolved from that. None of my skis have looked anything like a factory ski dimensionally - no matter how hard I try.

 

I hand shape the cores to fit in my mold and press them in under air pressure to follow the rocker and tunnel. Note that I don't shape the tunnel, I just slice the core so it easily conforms to the tunnel. The resin fills in the slits and enhances the bond from skin to core. The top of my skis are not flat (making binding installation interesting).

 

I make my skins strong enough that I can grind away the edges if I need. My edges are hand finished and often made from Superfil (epoxy microballoon paste).

 

Prepreg worked well for honeycomb cores but the foam cores I use can't tolerate the heat needed to cure the prepreg. So I haven't used anything but foam and wet resin for 20 years. The Applied Poleramic resin is fantastic with a reasonable pot life. Keeping the resin cool helps work time but a homemade prepreg would be tough as the resin gets very thick when cold so it won't wet out the cloth properly.

 

I use Graphite cloth reinforced with Boron unitdirectional fibers. A bit of Kevlar at the screw holes and occasionally some glass goes with my epoxy resin and PVC foam cores. And many many hours of work. Building skis is very expensive and time consuming.

 

If you want to tinker, get an old factory ski, a grinder and some superfil. Try your ideas with that. But do be careful, you will be grinding into the safety margin. Of course if you are just adding 1cm of width (no grinding of the original edges) to that old Goode to make it a new N1, you could have some fun.

 

Eric

[bbirlew]

Delete.... I should have read the new posts first!

[BraceMaker]

Considering Inserts - I've had great luck at work using 8-32 T-nuts, using scrap plastic I heat them up and press them through a drilled clearance hole such that the "teeth" are embedded, the barrel is clear. Then I pack the threads with clay/plumbers puddy and laminate them in place for solid anchors.

 

I know D3 has a "screw retention plate" they laminate into the Custom X. Could be a worthwhile direction if you aren't 100% on where the binding should be (atleast the RTP). Quantum goes the otherway and gives you 4 and says use their binding....

[Waternut]

If you use slow resins and/or work in cooler environments (ie not a hot summer day in FL), you can have upwards of a couple hours before the resin starts to gel much less heat up. Your total cure time will take longer though so you need patience. Prepreg makes life less messy but considering the amount of material in a ski, you aren't going to be saving weight or adding much strength with it compared to a wet layup and vacuum bagging. IMO, vacuum bagging is a must if you're building anything where weight and strength are critical.

 

If anyone near middle GA wants to try their hands at this stuff, I've got the vacuum bagging equipment and the know how to lay up composites. However, I don't have the knowledge of edge angles, stiffness, widths, etc. I read stuff here and there but it's hard to know if it's just marketing gimmicks or science and my skiing ability isn't consistent enough to say that worked or that sucked.

[BraceMaker]

So from a different industry, we do laminations in a different manner.

 

First we usually have a positive, and we build around it, and then remove our positive. So we do an inner bag (PVA) which we vacuum to the positive. Then our laminants, which are combinations of fibers, carbon, glass, Spectra etc. Once the dry laminants are layered appropriately, we add the second outer PVA bag, which we tape off, and apply vacuum, then we mix our resin, hardeners, pigment, etc. and pour into the layers from one end, while under continuous vacuum.

 

Then using the outer PVA bag and some nylon stockings, we string the resin into the layers to let it saturate and impregnate the fibers. Once it is sufficiently saturated, the source of resin is blocked off/clamped, the excess is strung to one end where excess fibers exist waiting to be cut off at a later point, vacuum is increased if you want to compact the fibers further, and the system is allowed to cure under ambient temps.

 

 

Our resins are usually acrylic or modified. Our positives plaster or expanded foam. No cores however.

[eleeski]

@BraceMaker Infusion molding works well with thick parts. My skis are one ply of carbon anywhere that is not heavily loaded. It would require a high quality system to pull resin evenly through one ply. A squeegee is almost as effective and a lot cheaper (with good visual feedback). A little pressure (or vacuum?) and you are close enough to optimal resin saturation. My skis are light and strong with a long history of success. However, I'd love to build an infusion boat or one piece jump ramp!

 

The standard woodworking inserts are superior to tee nuts because they can be replaced when they fail. Actually, today I repaired a D3 trick ski with a failed insert - it backed out with the screw when removing the binding. A bit of JB weld and a new insert and the ski is repaired. A molded in tee nut that failed would just be a permanent weak spot - if the binding would even come off (salt water is hell - even on stainless or brass). Plus, as a handmade ski, I'm not sure I could place inserts accurately enough to be right after my hand grinding finish.

 

@jfw432 Bring a vacuum system to San Diego. I'd love to try it. The one I tried didn't work well enough to make the ski follow the contours of the mold.

 

Eric

[RichardDoane]

@eleeski - if you spent the same amount of timing working on your skiing skills, instead of tinkering with skis, you're scores would go way up, and @horton would have a lot less to giggle about

[eleeski]

@richarddoane They used to say that about my trick skis. Now they are pissed because you are the ONLY non family one on my skis!

 

Eric

[rq0013]

For our first ski we copied a commmercial trick ski shape, added 1/8" more rocker and put longer grooves in the bottom for traction. We hand sanded and hot wire cut the shap after tracing the shape in the foam. We used bidirectional carbon with a sheets at 0 degrees and 45 degrees. Applied sqaures of carbon to reinforce the inserts we installed. Vacum bagged it for 8 hrs. It looked just like an elite ski or reflex trick ski. Pretty fun and cool to ride

[Horton]

@richarddoane I have been saying for years that Eric is clearly a very talented skier. His love for home made gear has held him back. On the other hand it does look like fun. If I had the time (and I do not) I would build skis that are way better than a LeeSki.

[BuoyChaser]

Great skiing Adam, great to see you rippin' it repeatedly in the course. Applying that well paid Mechanical Engineering degree and background in composite technology from pole vaulting. Can't wait to see what comes of it in production skis in the future!

[catman]

Nice work Dude, Adam has been our coach for the last couple of years and has helped me improve greatly. He was up here in NH just a couple of weeks ago and watched him ski into 38 on a coarse that is less than true. Very strong and technical is an understatement in my mind. The you tube vid is a clip of Adam, skiing 32 off in some rough chop, on #1 pond Sanford Maine couple years ago.

 

[Ntq206]

Wow - that's rough - you can hear it slapping the ski hard all the way.

 

Wicked recovery at 0:20 - yikes...

[alex38]

[BuoyChaser]