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Posted

Here's the other thing about a picket... the goal is large surface area. So all you could do is use the strength of titanium to make the picket less thick. That's a reduction of mass in only one dimension. On the other hand, a rod or a beam can be reduced in two dimensions -- the only important part is to retain the length. So, because of the purpose of a picket, significant weight reductions cannot be acheived without sacrificing functionality (surface area).

Posted

Titanium is actually about 60% more dense than aluminum (depending on the alloy comparisons one makes). By weight alone, titanium is not better than aluminum.

 

However, titanium is about 70% stronger (again, depending on the alloys compared). That is, most imporantly, its yield strength is 70% greater.

 

So, while a titanium picket would be heavier to carry around (1.3 lbs vs. 0.8 lbs for a long picket), you could beat on it to get it into firm snow with less deformation as a result (unless you pounded 70% harder).

 

Gary, your comment about the utility of a picket being tied to its surface area makes sense (frictional considerations), but this has nothing to do with the material used (well, not really anyway; there may be surface-ice cohesion considerations that come into play). If you wanted to use a titanium picket for the strength increase but also wanted to reduce the volume of the picket to get it back down to the weight of a similiar aluminum version, then yes, you would have a problem. A hollow picket, perhaps?

 

I'm certainly no expert on the engineering that goes on in producing a picket, but the foregoing is a general view of the matter. There's always more to it than one imagines or knows.

Posted

I'd be willing to guess that of the three widely availible pickets, MSR, Omega and Yates, that none of the three had any significant engineering put into them. I'm not criticizing them, as I don't think you really can engineer such a device for use in such a wide range of conditions, and a wide range of loads. I've seen thin angle iron with holes drilled in it used as pickets, and it seemed to work just fine and be just as "light" as the MSR extruded aluminum ones. When it comes down to it, these are very simple devices, the complex part (and subsequently the strength of the placement) as always comes form how the climber utilizes it.

Posted

I think there's also something about how the metal's behavior changes at cold temperatures. For example, a couple years ago BD was about to release a titanium-shafted ice axe, but killed the idea in the beta-testing stage becuase Ti becomes brittle in way-cold temperatures.

 

Of course, maybe that didn't really happen. It could've been a dream I had mushsmile.gif

Posted

Since we're all dreaming up stuff, why not mke a picket out of carbon or boron fiber. It's notch senseative, but it still might work. Please discuse.

 

Steve

Posted
Since we're all dreaming up stuff, why not mke a picket out of carbon or boron fiber. It's notch senseative, but it still might work.

It's an interesting idea. You could make one up at home even (cept CF is like $40/yd last place I went). You'd probably need an AL end caps or something, otherwise it'd be bashed to shit real quick.

Posted
You mean Titanium end caps, not that damn common aluminum.

I was thinking Aerospace Al at the minimum yellaf.gif With a special edition Ti model that's 10g or so lighter and costs twice the price.

Posted
You mean Titanium end caps, not that damn common aluminum.

I was thinking Aerospace Al at the minimum yellaf.gif With a special edition Ti model that's 10g or so lighter and costs twice the price.

 

Now you're thinking. You must be in marketing laugh.gif

 

Steve

Posted

You can get Ti and aircraft grade aluminum at the Boeing surplus store in Kent. I have seen some extrusions that look a lot like an 8 foot long picket. You might even get lucky and find a little CF lurking about.

Posted
Titanium is actually about 60% more dense than aluminum (depending on the alloy comparisons one makes). By weight alone, titanium is not better than aluminum.

 

However, titanium is about 70% stronger (again, depending on the alloys compared). That is, most imporantly, its yield strength is 70% greater.

 

So, while a titanium picket would be heavier to carry around (1.3 lbs vs. 0.8 lbs for a long picket), you could beat on it to get it into firm snow with less deformation as a result (unless you pounded 70% harder).

 

Gary, your comment about the utility of a picket being tied to its surface area makes sense (frictional considerations), but this has nothing to do with the material used (well, not really anyway; there may be surface-ice cohesion considerations that come into play). If you wanted to use a titanium picket for the strength increase but also wanted to reduce the volume of the picket to get it back down to the weight of a similiar aluminum version, then yes, you would have a problem. A hollow picket, perhaps?

 

I'm certainly no expert on the engineering that goes on in producing a picket, but the foregoing is a general view of the matter. There's always more to it than one imagines or knows.

Klenke, the Post Like Catbirdseat thread can be found in spray. Nice job, anyway. grin.gif
Posted

CF/Kevlar would actually work, never thought of it until someone suggested it. Expensive but not prohibitively so. At wholesale you could make a 2' and 3' from a 60" wide yard, and have some left over. Bend a stainless plate on top and some rivets, and you're golden. I may just have to try that :-) Now to decide between a U-section or an L... Maybe a c-section. Hahahahaha :-D

Posted
I think there's also something about how the metal's behavior changes at cold temperatures. For example, a couple years ago BD was about to release a titanium-shafted ice axe, but killed the idea in the beta-testing stage becuase Ti becomes brittle in way-cold temperatures.

There are tons of titanium ice screws out there and Ushba makes a titanium ice axe. Try a new rumor. wave.gif

Posted

seriously now: how often does anyone ever place a picket that is worth a shit in terms of holding a gnarly fall? if you have placed one that was great you cherish that memory cuz it happens so rarely. i reckon those things get used the most as massive tent stakes and the like.

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