Ski Builders Forum

So im starting my board construction for this winter. I am planning on making my own core out of downed trees from work. I did some research on here, and other sites and I see many people use 20 twenty five mm or so stringers for there core block. My question is what is the benefit of all the stringers. I was planning on doing 3 twenty mm stringers in the middle for the inserts and then two outer stringers. Is this a weaker core then one made entirely out of stringers?

IMO, the more important thing is to look at is the end of each board. When you look at the end of the boards, ideally you want the end grain (ie growth rings) to run vertically as much as possible. As for the number of stringers... hard to say. With more stringers you'll probably get a firmer board, more evenly flexing board because you're removing the changing grain structure that may occur in the wood. I wouldn't be overly concerned if this is your first board.

skidesmond wrote:I wouldn't be overly concerned if this is your first board.

right!

if your wooden board has no knots (and ideally vertical grains) you can use it as it is. glue adds nothing but weight.
there are hundreds of issues occuring once you started, and they might worry you more than the grain.
once your techniques are running, start with upgrading your process. not too much in the beginning.
that was a big mistake i made 2 years ago... lots of money and efforts, and then it sucked

My concern, milling lumber from "downed trees"?
While I think the idea's great the lumber will be more work than its worth.
Depending on the type of tree and how long it's been down (dead) you may have to strip and stack it for a year to get it dry enough to work with.
To buy the lumber at the local yard will be pretty cheap, a few clear 2x4s and a maple board or 2 and you'll have your first core put together in no time.
Small knots aren't a problem, despite contrary belief, as long as they aren't on your edge.
I've made cores that had knots the size of a dime, seen knots the size of a nickle in k2's and 4frnt's skis.

As the others have said don't get overly stressed about the type of wood.
Worry more about core thickness or building/finding all the jigs, tooling, and equipment you'll need to get this project off the ground.

Wood, when all is said and done, is just a filler and gives you something to screw your bindings to.
Have fun with it! Don't let your failures set you back.
Once this idea really gets in your head you'll be hooked.

sam

Sammer well said. I should have mentioned that the wood s/b kilned dried or sit in a dry place for at least 1 yr before using.

I've been using wood that was cut from a friends lot 20+ yrs ago. It sat in his parents basement the entire time to be used for projects that never came about. The wood is dry, but I spend a LOT of time sorting and matching the wood for cores. It's rough cut, most is 1.5 - 2+ inches thick. It takes a lot of planing and squaring up before I even start to make a core. The wood was free and very useful for other project too. But the trade off is time spent making it ready for cores.

oh yea...precondition for this easy going is that the wood is dry (less than 13% water i think), i forgot to mention.
thx guys

Stringers - dimensional stability, binding inserts, dampening, transfer of power into the edge set (more immediately relevant to snowboards) and enhanced bonding to composite materials. More strength - well your interrupting the natural pathways for any fractures that may develop when the board is ridden hard (depending on you choice of wood), so 'yes', in that it is probably more durable as a result.

I agree with all of the above, except the thread 'third board' means it may well be possible to nail it first time. You definitely want wood that has been kiln dried - particularly if you are heat curing your epoxy. Pressure treated sidewall material if you are confident the board is going to be ridden the whole season. Google 'Mechanical Properties of Wood' if you want more detail.

Enjoy the ride!

You said wood.

thanks guys for all your help! unless I can dry this my self it looks like the trees i had in mind will have to wait till next season. How exactly do they dry wood at lumber yards or where ever they do it?

Great big kiln, lots of heat and moving air.
Like a giant convection oven.
If your just gonna let mother nature dry them you'll want to cut them into slabs and stack them with stripping (boards between each layer) so that air can get to all sides, cover them with a tarp and give them a couple years.
Probably couldn't hurt to rotate your pile after the first year.
Like I said way less effort to get buy the boards you need.
I've got a pile of rough fir and larch 1x4s that I pick thru from time to time but of the 300+ boards in that pile only maybe 10 were usable for skis.
the rest made some nice trim for my house and I still might make a fence or something

sam

wish a i had a kiln then. IM sure it still takes a long time with one though. Some point i want to make a core out of some recycled trees. but sounds like not my first one. Would you suggest making one out of lumberyard scraps or buying a pre-made core? Oh YA and what about pallets? I hate seeing them go to a burn pile and i always thought it be awesome to make a core out of one.

Pallets have been used before, do a search on it. Also you can build a small kiln. It's basically a box with a low heat source and a fan to move the air. I had plans in a woodworking magazine... bet you could find plans on the internet.

I was about to start a "Pallet project"(the search term) since I got a huge pallet send to me. But it was too dirty and full of all kind of sh*t(nails, rocks etc...). I didn't want to risk my blades in the planer. Maybe later when I'm about to change the blades. It will go in the fire place instead...

All of the thin stringers are about dimensional stability. As was mentioned above, you’re trying to end up with the grain running vertically, from base to top all across the board. Such a core will retain its shape over time in your shop. If you could get a perfectly quartersawn board wide enough then you’d just use that and skip the stringers, but clear and wide quartersawn boards are rare and expensive, so we manufacture that with all of the stringers.

This might help: http://www.happymonkeysnowboards.com/Mo ... k_overview

The items under Wood and Wood Science here are excellent references for just this kind of stuff: http://www.happymonkeysnowboards.com/Mo ... _Resources The first book is a must-own kind of item.

This video will explain drying perfectly for you: http://www.finewoodworking.com/Material ... x?id=29500 I should add that to my woodworking resources page, I forgot about it!

Enjoy!

Edit: fixed woodworking resources link.

Dimensional stability can be achieved with a heat cycle - e.g. pine used for wooden pallets (30 mins @ 56 degrees). Kam did a write up of his pallet project.

The wood science link doesn't appear to work, but it must be pointing at something like this: http://www.fpl.fs.fed.us/products/publi ... eader_id=p

@ 1.26 is worth a look to see all the things the stringer can do for your board.