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Ti biners?


Dustin_B

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At the risk of sounding like an idiot, why don't companies make titanium biners? The cost issue seems like a weak arguement considering the other items people buy just because they are made out of titanium. With all the talk recently (within the last year) about biners breaking seems like a logically solution (in some cases). It seems like those heavy steel rescue biners could be replaced with Ti too.

 

Same thing for crampons. I haven't seen any Ti crampons.

 

If I'm on to something here please don't steal my idea and make lots of money off of it. grin.gif

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JoshK said:

Titanium is also quite brittle as I understand. I wonder if this would play into the choice to not use it in technical gear??

 

My understanding is that Ti is preferable for bicycle frames partly because it fails more gradually than aluminum -- aluminum snaps with no warning, with Ti and steel both deform gradually before failing. I'd guess the same thing would apply to biners.

 

Seems like I remember reading about Messner using titanium crampons during his solo ascent of Everest way back when.

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Yes, pretty hot. A friend of mine works for a company that makes Ti exhaust systems for motorbikes, and we had a chat about this not so long ago. It seems to me that he also said that there are problems with casting Ti, and that it is typically, or perhaps always (sorry I forget) either machined or extruded. At this point in the design life of biners, they are made of cast items.

 

BTW steel biners are still in use in other applications where weight is less of an issue.

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There is russian brand of Ti biners called Irbis. THey were produced since early seventies

in regular and lock versions and available in Russia now. Not so great, little bit heavy (77g)

and small for the same strength as aluminum. Actually it is not pure Ti as Ti is very soft material.

All "Ti" gear is made from Ti-Vanadium alloy, strength and other properties depend on V content.

You can machine this alloy, bent it etc. but for the strength you need to do thermal treatment.

Back in 80's I made couple dozens of biners from Ti-V, destroyed half of them for strength testing

and used happily for last 20 years, still have one left in use. That was very nice shape (triangular with lock)

that I copied from old steel biner from 50'

Oleg

 

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Here's my take on why they don't make Ti carabiners. Titanium is more dense than aluminum. Therefore, if you wanted to make the biner the same or less weight than the Al one, you would have to either use a thinner stock or make the entire biner smaller. You don't want to do the former because it would break the loaded rope because of the smaller radius and you wouldn't want the latter because you couldn't easily fit the rope through the gate.

 

You may have noticed some of the newer biner designs are hollowed out or otherwise have grooves in them. The logic behind this is to remove metal while maintaining the radius that the rope must turn over.

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I think Lowe/Camp made TI footfangs for a while and sold them in Europe at least. As far as I know nobody in the CIS made them. According to some Russians I spoke to once Ti suffers from fatigue problems and they break unless you grossly overengineer them, hence no TI crampons from the CIS. I suspect that this was less of a problem for the somewhat overengineered footfang. Maybe better quality metal too.

 

I also have one of those Irbis biners. They're heavier than a Al biner but lighter than a steel one. The Russians swore by them, thought our lightweight Al gear was a bit crap. Said they were especially good for aiding as the Ti is harder than Al so doesn't get chewed up. The other issue with making light Ti biners is giving them a large radius of curvature for the rope to run over while reducing the volume of metal.

 

Those guys were so cool. All their gear was made by them or their friends. They had wires, biners, screws, tents all made locally.

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allison said:At this point in the design life of biners, they are made of cast items.

 

What makes you think that? Black Diamond would disagree with you -

 

"The first wing, the second wing and the bridge are stamped or otherwise cut out of a sheet of metal or other durable, bendable material. The wings are then bent relative to the bridge so that they oppose one another and form sides of the gate. "

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Alright kids, I should be studying right now, but seeing as this is 3x more interesting than my day job, I couldnt resist.

 

I contend that cost is the main reason we dont have ti biners. Even with the "cheap" ti ice screws etc that we see these days they are frequently from our friends east of the Berlin wall and hence can produce some really cheap gear. This doesnt mean that it is well designed, uses appropriate (or even quality) materials, or is well constructed; it only means low cost.

 

As far as some of the other issues batted around:

 

-Hardness- this is completely alloy dependent. It really is not appropriate to just say "Ti" and "Al" and leave it at that. There are worlds of difference between CP Ti (commercially pure) and 6Al/4V Ti, just as there are worlds of difference between 7075 AL and 2024 Al. Then we have heat treatment, etc issues entering as well. If we want to compare 7075 T-6 Al (stuff ATC's are made of) with 6/4 Ti then alright we can have a meaningful discussion about their physical properties. I can assure you that the aluminum will win in terms of cost though...

 

 

-Ti brittleness- If you cold work Ti (by bending it into a carabiner frame) and dont heat treat it to relieve the internal stresses you could potentially produce a very brittle product. Heat treatment, when done correctly can completely circumvent this problem (this adds cost though). Note: within limits, many Al alloys dont have very significant problems with this. That is why so many of our biners are "cold forged" (ie. formed at room temp).

 

-Fatigue life- Ti generally has a much higher fatigue limit than either Al or steel. So if you take 3 identically sized/shaped bars of the above 3 materials, and you flex each of them a large number of cycles (with the same load)without actually deforming them ***generally** Al will fatigue (and break) first, followed by steel, then by Ti. It is an intricate concept to explain, but the fatigue life of ferrous materials (ie. steel) is based on a unique physical phenomenom that Al and Ti dont exhibit, so it really is difficult to make rational fatigue comparisons b/w ferrous/non-ferrous materials. Al vs. Ti is fair game though.

 

 

-Hard to work- yeah, but if you want to pay enough money, we can easily get around this.... What "hard to work" really means is that the standard machining, casting, welding processes for steel/Al arent applicable to Ti, so if you want to use the exotic metal you have to go to some extra lengths to be able to manufacture something from it. (incurs more cost) A great example is welding Ti, it must be done in an inert gaseous (Argon) environment b/c if there is any Oxygen (or a spec of dirt) around when the metal is heated to 3000 C it will react with the Ti and produce a weak spot. Thus we CAN machine/weld/cast Ti, but be prepared to pay for it.

 

allison said:

It seems to me that he also said that there are problems with casting Ti, and that it is typically, or perhaps always (sorry I forget) either machined or extruded. At this point in the design life of biners, they are made of cast items.

 

 

Ummm...no. Biners are either cold worked/cold forged (which means shaped using a lot of force, at room temp) or are hot forged in order to produce more intricate shapes. From a cost to produce standpoint, and a strength/quality standpoint, we are better off bending them from straight bars of the parent metal as opposed to casting them, regardless of the material used.

 

The bottom line is this----------------------------

 

For the low, low price of 5 dollars we can get a biner that is perfectly strong enough, fairly lightweight, and predictable in terms of its limitations. There simply is no reason to chase down a more expensive material just to make a Ti biner. If you are worried about strength, just make them with 20% larger parent metal stock, and you will get a biner that is 20% stronger. It will still be cheaper than Ti.

 

Happy Monday everyone....

 

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