J2Ski Forum Posts and Replies by Dave Mac

Ise,

Theoretically your thoughts on salt based corrosion have a murmuring of truth.

When the stress reversal situation is in air, the S-N curve flattens, lets say for a particular material at 300N/mm2. If this takes place in the presence of water, the base stress reduces to less than 200N/mm2. However, in a Sodium Chloride solution, there is no fatigue load base limit, and failure occurs at a much lower number of cycles.

But you have to remember, this is not an occasional skis-on-roof situation. This is a skis operating in the sea situation, it doesn't happen. And on your roof rack, stress reversals are not occuring, you ain't skiing at the same time.

I don't think that ski engineers would choose an incorrect spring material, so I agree with that.

When Pavel mentioned off-season spring relaxation, I thought it was a reasonable idea. I don't think that it does any harm.

Another empirical aspect to this discussion, relates to the nature of the individuals, and how much skiing they do. A few people on J2 are fortunate enough to do more than the regulation 2 weeks a year. Most of those, plus I am sure many others, ski at a fairly swift pace, for most of the time. In the event of a fall at speed, a Din 7 setting would pretty well ensure that the skis exploded away from you, quite desirable, should you be dilligent about keeping your edges sharp.

Spot on Trencher, creep wouold permanently change the spring length, and therefore it's resistance force. However, when the spring is at a low tension for an extended period of time, the creep effect would be minimal.

How minimal this is does depend on the ski binding design. If there is a spring that remains under a heavy tension when the binding is not in use, that would exhibit greater permanent deformation that a spring under lower tension.

I am not expert in binding design, so could not comment.

I used to set my bindings at DIN 5. My logic being that having a dodgy knee, I want to avoid a slow twisting throw-out with a higher setting. This changed when, on steep, heavy, wet off piste, the ski jammed into soft stuff, and I walked out of it. The loose ski then took off. The brake didn't work because the snow was soft, and I had a 300 metre hoof down on one ski. That night, I reset the Din to 7, where it has remained ever since.

I'm afraid to confess that I bench test my bindings by hitting the side of the boot sideways, so that I can "feel" the binding retention force.

Old habits......

Hamish,

Re the room direction, email the Harfenwirt, (Google Harmony hotels or Harfenwirt) and just ask. Explain that you always have stayed at the Vicki(for 6 years), but are now trying the Harfenwirt. You always went to the Vicki because of the mountain view, and is it possible to have a room with a view of the Marbachjoch.

Herbert is totally market driven, and unless he has other preferred users, may well look on this as a way of gaining a long term customer.

You have been in Summer before. What walks have you done? We have, assuming going up the mountain by gondola: -
1) Rudis, Kasealm, (Cheese making farm, Horstieg, (tiny hut with photos of deceased Wildshonauers, Anton Graffe hutte, down the Hochberg.
2) Rubeszahl, and down Tennladen
3) Rubeszahl, and down the back of the Marbachjoch to Penningdorf.
4) Postbus to Worgl, then to Hopfgarten, climb up through the woods back to Niederau.

I think the Kundl Klamm is still closed, due to a rockfall, (it hit a German lady) last summer.

Any other interesting ones?

Firstly, thanks to Pavel for the award, commiserations to my fellow conspirators.

Now, this thread has developed into an area, about which I do know a small amount.

The skiseekers article/binding maintenance/section 7, refers to fatigue in the binding spring.
Fatigue is a function of stress reversals, characterised by the stress reversal range and the number of reversal cycles. It is famously demonstated by the S-N curve, which is particular to specific materials.

Fatigue life is affected by other factors such as temperature, surface finish and residual stresses.

But.... the mode of failure by fatigue is by crack evolution, and fracture.

How many bindings in the world have failed by spring fracture?

Anyone?

I think they may have the failure terminology wrong. If not, then I think they are just wrong.

The most likely effect on a binding spring is creep. Creep affects all solids under load. A good analogy is the flow, under self weight of medieval glass. However, creep effectively exhibits at a reasonable elevated stress, (loading). This is markedly influenced by elevated temperatures, but that is not an issue for us.

So creep will affect our binding springs, the question is, to what extent. I discount the dynamic effects, (ie effects when we are actually skiing), because this is a relatively small percentage of the spring life. We are only really discussing the static effects, when the ski is in storage. Under low load, we might expect the spring to undergo creep, but that this will be very small, and for practical purposes not measurable.

The failure mode for creep is a reduced length, when under sustained compression, or vice versa for sustained tension. So, when the binding is not in use, but the spring is active, there will be creep, but in a well designed binding, this will not be measurable.

Man, I have just lost the will to live, I just want to point downhill.

Ah Tony, your such a big softy, letting them of with broken windows.

Three summers ago, getting on a bus in Pisa, an American chap threw his child trolley on board, whacking my OH on the head, and producing a muckle bruise. Getting off the bus, I mildly suggested he was ignorant, and an Ar..h..e, to boot. He proceeded to whack me across the head.

Off the bus, I lowered my rucsac to the ground, and mild mannered man that I am, leaned back on to the bus, grabbed him by the Gho....s, twisted, and pulled, whereupon, he shot over my shoulder, complete with ripped jeans, at the appropriate area, and landed on his feet. Given that he was less than half my age, I did think there might be some ensuing action, but none there was.

Brought a whole new meaning to the word "Yank"

I organise group holidays with friends every year, pay on my visa, and don't seem to have any bother.

Sorry Pav, I didn't realise this should be ten only. As it happens, the exercise has turned out a fairly comprehensive to-do list. The only problem is that I am now up to thirty two must-do items.

No, none of this is shotgun. Every point on my list hits a target.

I couldn't possibly discuss prizes, in advance, as my Austrian friends say to anticipate receipt is to bring bad luck.

It might be that racing gloves would be too fast for me! I have a little chuckle about sizes. I think I moved from medium to large when I was 13 years old.

And finally, I normally take 6 hours sleep a night, and Nothing keeps me awake. Mmm, well, nearly nothing.

Rosfrae 8 wrote

On the edge of control, if not just a bit over it, thats how you win.

Rather like Franz Klammer in the 76 Olypics, right knee just above the right ear. He later said he was just in control.

I cannot do ten! I try to prioritise, but I have to do them all.

1) Rear entry boots, perform well but need a couple of tightening cables replacing and edges smoothed off.
2) Strip bindings on K2s, degrease, and apply new grease. Take to Niederau next winter.
3) Same procedure on Rossignals, based in Niederau, do in July.
4) Fill sharpen and wax K2s and one other pair.
5) Replace pole baskets, one has split.
6) Review winterpacking list. Managed to get rucsac weight down to 14Kgms, including ski boots and painting gear. Can do better.
7) Cut a bit from the upper centre of goggles, don't wear them much, but when you need them.....
8)Buy new ski gloves and salopettes. Glove thumbs now 90% duck tape, 10% glove.
9) Try to get my lovely Wildsconeau Ski Race Club sweater repaired. It's over thirty years old, and showing the odd hole. But those proud gold dragons on dark blue...
10) Maintain/resume daily ski-specifice exercise routine. This is a big commitment, with a big payback.
11) Finalise research into Austrian beginner and experienced skiers ski week for next New Year.
12) Arrange Jan & March Niederau ski fortnights and one other ski week.
13) Search for a buy new photo frame for an old Manchester friend, long since buried in Niederau, after a ski accident. I take responsibility for the grave maintenance.
14) Learn all the words of "Kufsteiner Lied" I do a John Redwood on most of them, the Austrians don't realise this yet. I just enjoy the yodelling.
15) Have promised Herbert blow up photos of times past in Niederau, for the walls of the Harfenwirt extension. Already am consulting all my older ski friends, (just in case you think I'm part of "times past".
16) Replenish my winter first aid pack.
17) Consider commitment to assisting with Disabled Ski Club.
18) Find out how to load pictures from my computer onto J2ski.
19) Organise dry slope/Xdome lessons for two friends in our village, taking their first ski trip next winter.
20) Buy another ski bag, forgot that I left mine in Niederau.

That's enough, I know there are heaps more. However, this has turned out to be quite a good exercise in creating a "to-do" list.

With all the building projects, tennis, hill walking, dog training, mountain biking, painting the outside of the house, blah di blah, how am I going to get through the ski list?