Ski Builders Forum

As I read around on strange lumber websites (don't ask why), I have learned about the super dense wood called Ipe. I have heard of people using it in skis, but only in the sidewall. If I wanted a super stiff bomber ski, do you think I could use Ipe in the core? Has anyone experimented with Ipe or other super-hardwoods in the core?

Yep. I built one pair having a vertically laminated core comprised of three layers of Massaranduba and four layers of Poplar, alternating. These have a similar profile as my other skis so I can compare their performance. Results are a heavier ski that is somewhat stiffer, duh.

I've since learned to stiffen skis by adding strips of unidirectional carbon fiber top and bottom, and make the core a little thicker for really stiff boards. Adding Ipe or Massa in the core adds too much weight. Profile geometry and composites are better methods for controlling ski stiffness. Keep the cores light.

-S

Well, when it comes to making a super stiff core, perhaps you have heard of DPS. I've seen a cut away of one of their skis and what they do with their metal is sandwich it in between the strips of wood in the core. Obviously, that's a great idea. But, just for the heck of it, what do you think would happen if you replaced the metal running along the strips of wood in the core with carbon fiber? I know that has nothing to do with my original Ipe question, but I am too lazy to post a new topic about it.

It would be A toxic nightmare to machine the core.
But great idea.

Yes, adding a denser wood will give you a slightly stiffer core.
It will also add weight and cost.
Adding a 1/2mm of core thickness will give you a stiffer core without adding much to the weight.
Exotic woods may have their place, but to make a stiffer ski IMO, is a waste of time/money.
Save the money, make your core as light as possible and make your stiffness in the thickness or add a bit of CF.
Go and look at I beam construction, your ski is an I beam, the core is the web.
1/2mm thickness makes a huge difference in overall stiffness of a ski.
I think we went thru all this a few years ago, it's ski building 101.

I'll say it ad nauseam, read thru everything on this site, The guys who have stuck it out here for the last few years didn't ask questions that have been answered a dozen times.

I don't want to be a dick but somebody has to keep saying it over and over and over and over and over and over and....

Yes, adding something eg; metal, CF, etc, between the strips of your core will add stiffness. It's been done in house construction to make beams stiffer. No reason it wouldn't work in the web of your ski.
This has been discussed before as well.
CF would work great for this but as MM said wear a mask when you machine your core. CF dust would really be good for ya!


sam

hasn't another company this year added the vertical aluminium to their cores? I thought I read it somewhere the other day. I thought DPS patented it, but I think theirs was stainless steel.

I like the idea of carbon in the core between the stingers but that means epoxying the core or using a prepreg and curing it or precured stuff, Sounds like a lot of work.

You could always cure a sheet of carbon fibre and epoxy and then cut the profile of your core out (either CNC or using a template). Then profile your wood core and rip it into pieces before then sticking them all back together. Would be fiddly and a lot of work, but would stop you having to send the carbon fibre through the planer. You could just do this during the layup rather than regluing the core before layup. As long as you had good lateral support to the core (eg. milled cassette) pieces when they all went in.
If you were making a lot of cores and didn't mind the "toxic nightmare" of profiling with embedded carbon fibre you could laminate sheets of wood together as usual with layers of carbon in there, then resaw your cores on the bandsaw.

Edit: to my above post. I had read the Atomic Automatic for this year has titanal stringers built into the core. I thought this was like the DPS method but watched the layup video and it looks like there are just 2 narrow stringers recessed into the core givng some added stiffness underfoot + more secure binding mount.

Dampening in the forebody of the ski me thinks on the automatic.
i heard amag stopped making titanal.

Here's the vid
http://www.youtube.com/watch?v=i6AH4uOR1Rk&sns=em

Had the idea of doing vertical carbon inside a core forever. One of the reasons I've gotten myself into the mess of ski building. I don't think it would be terrible to profile either, just need some good ventilation/dust collection system and a respirator. I am curious what it will do to bits and blades though.

Pretty sure it would have massive benefits for a ski if pulled off right, super thin and lightweight cores, but still extremely stiff. Even subbing out the carbon for glass would be amazing.