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choice of wood

Posted: Sat Mar 29, 2014 3:57 am
by MadRussian
for now I build skis with wood what I had which is Maple and popular. Last two basswood used instead of popular.

I'm looking at wood property chart and Maple and Ash have almost identical properties as far numbers. Is there any difference between Maple and Ash as far ski performance. The only noticeable difference for me right now was that the ash were heavyer in the same size boards.

How about Hickory? iirc back in the days of wooden skis Hickory was wood of choice.

Posted: Sat Mar 29, 2014 10:25 am
by MontuckyMadman
bamboo not a wood but has great properties for skis.
hickory in my experience has a tendency to be brittle.
sheck this
http://www.praxisskis.com/product_image ... 24x295.png

Posted: Sat Mar 29, 2014 3:14 pm
by MadRussian
MontuckyMadman wrote:bamboo not a wood but has great properties for skis.
hickory in my experience has a tendency to be brittle.
sheck this
http://www.praxisskis.com/product_image ... 24x295.png
For now I don't want to use bamboo. Trying to stay with locally grown trees
When Hickory is brittle while machining or in the skis? Are you suggesting Hickory is not good wood choice for skis?

For sometimes I thought to combine maple and ash. Now I have some ash and can do that.
Praxis example do not explain my original question. What difference between Maple and ash while physical properties like density and Modulus of elasticity very similar. In fact it add another question what is the difference between Aspen and Poplar because they also have similar physical properties

Posted: Sat Mar 29, 2014 6:30 pm
by MontuckyMadman
Saying they are similar means they are not the same. Aspen is softer. Ash and maple have different properties. Ash is damp maple is stiff. Poplar and aspen are both "filler" woods with decent mechanical that are light in weight.

Posted: Mon Mar 31, 2014 3:03 pm
by Richuk
It might be worth treating the charts as indicative, given that you will be dealing with local resources and mixing these with other wood species. If I remember rightly, you need to adjust the figures and compensate for different moisture contents in the figures shown. Perhaps it is worth comparing samples using a three point bend test - just to get your eye in?

Although stiffness is a factor in the design of the core, when in service you will be subjecting it to 'work', which points you in the direction of fatigue.

How fatigue resistent a wood species is, or can be made, will depend on how porous the wood species is. Check here: http://www.woodanatomy.ch/ident_key.html Certain soft wood species are better than others.

Wood cores

Posted: Thu Apr 03, 2014 3:34 am
by Cameloth
I have some good quality Birch left at my shop:

http://cameloth.eu/nl/shop/hardware+%26+diy/supplysale

It goes for 24.95€ per core. Very cheap I'd say.. There's still 21-24 cores left. If you pick them all up then we have a deal for 500€

Mail me at info@cameloth.eu

Posted: Sat May 24, 2014 3:33 am
by MadRussian
How about Oak? What characteristics oak will add to the core? Chart properties for red and white oak similar to Maple.
Also how about white oak for the sidewall? They used to build boats with white oak.
IPE nice-looking but pricey and, to my surprise, relatively easy to get damaged, chiseled away by sharp edges and binding breaks.

Posted: Sat May 24, 2014 10:48 pm
by Dr. Delam
I have used some oak in most of my cores. I only put the stringers under the binding holes though. It is a bit on the heavier side and will add some dampness to the skis which I prefer. I haven't used it for sidewalls though but I imagine it should hold up reasonably well.

I am surprised you found the ipe to be easily damaged. I haven't built skis with it but used it for decking and it was hard on tools.

Posted: Mon May 26, 2014 1:54 pm
by MadRussian
under binding screws I use Maple have some Ash. Oak is local easy to get and obviously cheaper. For the damage I got IPE doesn't seems like worth of premium I like the collar that's about it

It's took me a while to figure out where the damage from. Marker Griffon have very sharp breaks
Image

Sidewall got like chiseled out from under knees of top fiberglass. Damage occurred very quickly then maybe half a day of skiing at best. Sidewall bevel 14°. For some reason damage happening only on one ski

Image

Posted: Mon May 26, 2014 10:33 pm
by pmg
Well that sounds a lot like one of you ski breaks is a bit bent and hits the sidewall because of this. The ski break shouldn't touch the ski at all when moving.

Posted: Wed May 28, 2014 4:48 pm
by MadRussian
pmg wrote:Well that sounds a lot like one of you ski breaks is a bit bent and hits the sidewall because of this. The ski break shouldn't touch the ski at all when moving.
breaks are fine. Shouldn't .but... It is what it is... At least I know where the problem and will fix it

Hope can continue on original subject of this thread different type wood and it characteristics

what is the difference in characteristics to the skis from red and white Maple and red and white Oak

Posted: Wed May 28, 2014 5:17 pm
by gav wa
I find the points raised by Richuk about wood fatigue to be the most interesting. After reading it I started researching it and it seems not a lot of technical research is easily available. The stuff about the design and layout of the pores of different wood species is good and seems to really be a factor in choosing different wood for what you want from a core.
With materials being so expensive here in Australia we cant afford to do heaps of trials. So for me trying to work as much out before starting a new board is a big deal.

Posted: Wed May 28, 2014 7:36 pm
by gozaimaas
My paulownia/bamboo boards are nice and light and feel great to flex. Persinally I find tge biggest variable is core profile and thickness. Most of tge factory boards I have cut up have pretty shabby looking cores full of finger joins.

So Imo get some bamboo and mix it with something light

Posted: Thu Jun 12, 2014 3:04 pm
by loganimlach
Am I the only one that's not very impressed with bamboo? Having ridden on some Moment bamboo prototypes and making my own bamboo skis, I much prefer stacks involving aspen, ash, maple, alder, etc. Although I will say that I the bamboo sidewalls I put on my ash/alder/paulownia skis worked well.

I just feel like bamboo skis are, for lack of a better term, "lunky". Then again maybe I just haven't been on the right pair yet. I'm focusing a lot of energy on Alder, I love it's characteristics as a filler wood.

Posted: Thu Jun 12, 2014 3:42 pm
by gozaimaas
loganimlach wrote:Am I the only one that's not very impressed with bamboo? Having ridden on some Moment bamboo prototypes and making my own bamboo skis, I much prefer stacks involving aspen, ash, maple, alder, etc. Although I will say that I the bamboo sidewalls I put on my ash/alder/paulownia skis worked well.

I just feel like bamboo skis are, for lack of a better term, "lunky". Then again maybe I just haven't been on the right pair yet. I'm focusing a lot of energy on Alder, I love it's characteristics as a filler wood.
I know exactly what you mean. I built 2 boards with 50% bamboo 50% paulownia. One with 4 lengths of 80mm wide carbon tape and one without.
The one without feels "lunky" and very flexible, the one with carbon is snappy.