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miklaw
Mar 11, 2009, 1:27 AM
Post #1 of 22
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Registered: Jan 13, 2004
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This biner was removed from the top of "These People are Sandwiches" at Shipley NSW Australia. It was a single point lower off and looked like a nice stainless wiregate. An eagle eyed climber saw a fine crack (possibly it was more open under body weight) and retired it. At this point it looked like a standard bent wire biner with an unnecessary weld in it.
I was eager to see if there was a weld defect that caused the crack, so broke it in gate open mode to try and preserve the fracture surface.
It broke at 169 kg (372 lb). Wow.
The strength with the gate closed is difficult to estimate, the gap between the wire gate and notch was 3.5 mm, under load the gate must have engaged otherwise it probably would have broken in use. Lets assume the unit would have held twice the breaking load or 338kg or 744lbs.
On inspection it was cast and had a shrinkage defect in it (across about 30% of the shaft). The edges of the defect were probably fused closed and thus looked ok when it was new, they appear to have torn under use. There was a dimple at the end of the crack (just visible) showing some plastic deformation. After sectioning a number of other things were observed.
1) The significant corrosion inside the crack was probably an “original sin” being high temperature oxides that formed in the hot tear during casting.
2) Amazingly there was a weld repair at one point also
What does this teach us?
It’s better to have redundancy, twin independent anchors
Be careful using non-climbing gear. Cast gear is particularly variable in strength, fatigue strength, toughness etc.
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biner1.jpg
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biner3.jpg
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adatesman
Mar 11, 2009, 1:40 AM
Post #2 of 22
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miklaw
Mar 11, 2009, 1:44 AM
Post #3 of 22
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No markings anywhere, just a number 10 on it (diameter in mm?)
A local has been rebolting and shelled out his hard earned for these, they look bomber, not unlike the nice Fixe product, but are obviously very much weaker.
Thanks for posting the photos
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angry
Mar 11, 2009, 1:49 AM
Post #4 of 22
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Registered: Jul 22, 2003
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Do you know the intended purpose? If they're not climbing gear, I don't really know what they are.
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miklaw
Mar 11, 2009, 1:53 AM
Post #5 of 22
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marine accessory biner?
clipping dog/child to leash/ back of pickup?
clipping waterbottle to pack?
I don't know, but there appears to be a market for them.
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angry
Mar 11, 2009, 2:04 AM
Post #6 of 22
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They just look a lot beefier than the toy stuff. Even an old retired biner would be better.
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miklaw
Mar 11, 2009, 2:14 AM
Post #7 of 22
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Agreed, any old climbing biner would be better. We will have a posse replacing these ASAP.
I mostly posted this result as the low strength (because they were cast) surprised (and terrified) me, and I was concerned that they may be available in the US. I still haven't found where they came from
(This post was edited by miklaw on Mar 11, 2009, 2:37 AM)
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rschap
Mar 11, 2009, 2:32 AM
Post #8 of 22
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I repair cast (alum, ss, steel) all the time at work, it’s brittle, very brittle. I would think one hard hit against the rock would be enough to fracture it. Beaners need to be rated or they’re only good for holding up your chalk bag.
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bill413
Mar 17, 2009, 2:47 AM
Post #9 of 22
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Registered: Oct 19, 2004
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Man, that's scary. i do wonder what the intended purpose of these biners was.
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acorneau
Mar 17, 2009, 3:02 AM
Post #10 of 22
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It looks a lot like the Wichard biners (made for marine/boating purposes), although this one is welded so I can't be sure:
http://
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billcoe_
Apr 18, 2009, 6:20 PM
Post #11 of 22
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In either case: as they seem to look good (before they break:-) , I speak for all of us, and thank you for the heads up Mikelaw.
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maldaly
Apr 18, 2009, 8:16 PM
Post #12 of 22
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Registered: Oct 31, 2002
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I'm astonished that you think that is cast. Why do you think so? Of all the methods for forming metal to make a carabiner, casting would be on the bottom of most people's list, including mine.
The design is modeled after the Wichard marine hardware carabiner. Wichard products are very well made, extremely strong and quite pricey. The Wichard 'biner of that shape is cold forged (bent) and welded. Rich sailors use them to moor their $20M sailboats. West Marine currently lists that model for $37.99 All Wichard products are marked with a "W".
I've seen some Chinese versions that sell for less than $12 that are only marked with a numeral indicating the diameter of the stock. In this case, 10mm.
Choose your gear carefully,
Mal
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reno
Apr 19, 2009, 9:50 AM
Post #13 of 22
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miklaw wrote: It was a single point lower off
Kinda surprised nobody mentioned that little tidbit yet.
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scrapedape
Apr 19, 2009, 1:38 PM
Post #14 of 22
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Registered: Jun 24, 2004
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reno wrote: miklaw wrote: It was a single point lower off Kinda surprised nobody mentioned that little tidbit yet.
miklaw wrote: What does this teach us? It’s better to have redundancy, twin independent anchors |
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erick
Apr 19, 2009, 1:57 PM
Post #15 of 22
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Registered: Aug 12, 2005
Posts: 191
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dang. thats pretty effed up.
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miklaw
Apr 20, 2009, 12:46 AM
Post #16 of 22
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maldaly wrote: I'm astonished that you think that is cast. Why do you think so? Of all the methods for forming metal to make a carabiner, casting would be on the bottom of most people's list, including mine. I agree casting would the last option for strength and reliability, but it is cheap. Why do I think it's cast? 1. Fracture appearence showing both a high temperature (oxidised) defect and dendritic structure. 2. Metallrgical examination showed large dendritic cast structure very similiar to ASTM standard cast structures. 3. Independendent confirmation by a (45 years experience) metallurgist 4. Presence of weld repair of a large defect, proabbaly autogenous with a TIG torch, the grain size in this was less than 1% as big
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rschap
Apr 21, 2009, 12:08 AM
Post #17 of 22
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Registered: Sep 30, 2005
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I’m astonished that you quoted the post without adding anything to it, that’s almost as good as the second poster in the thread quoting the original poster like we don’t know who they are responding to.
(This post was edited by rschap on Apr 21, 2009, 12:09 AM)
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notapplicable
Apr 21, 2009, 12:28 AM
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rschap wrote: I’m astonished that you quoted the post without adding anything to it, that’s almost as good as the second poster in the thread quoting the original poster like we don’t know who they are responding to. |
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desertwanderer81
Apr 22, 2009, 8:41 PM
Post #19 of 22
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Registered: Sep 5, 2007
Posts: 2272
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miklaw wrote: This biner was removed from the top of "These People are Sandwiches" at Shipley NSW Australia. It was a single point lower off and looked like a nice stainless wiregate. An eagle eyed climber saw a fine crack (possibly it was more open under body weight) and retired it. At this point it looked like a standard bent wire biner with an unnecessary weld in it. I was eager to see if there was a weld defect that caused the crack, so broke it in gate open mode to try and preserve the fracture surface. It broke at 169 kg (372 lb). Wow. The strength with the gate closed is difficult to estimate, the gap between the wire gate and notch was 3.5 mm, under load the gate must have engaged otherwise it probably would have broken in use. Lets assume the unit would have held twice the breaking load or 338kg or 744lbs. On inspection it was cast and had a shrinkage defect in it (across about 30% of the shaft). The edges of the defect were probably fused closed and thus looked ok when it was new, they appear to have torn under use. There was a dimple at the end of the crack (just visible) showing some plastic deformation. After sectioning a number of other things were observed. 1) The significant corrosion inside the crack was probably an “original sin” being high temperature oxides that formed in the hot tear during casting. 2) Amazingly there was a weld repair at one point also What does this teach us? It’s better to have redundancy, twin independent anchors Be careful using non-climbing gear. Cast gear is particularly variable in strength, fatigue strength, toughness etc.
What scares me is that people have apparently been rapping of this carabiner for quite some time.
Shame we can't find out who actually put this carabiner on the climb.....
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desertwanderer81
Apr 22, 2009, 9:00 PM
Post #21 of 22
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As long as they're not placing that junk in MY country :P
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mikes
Apr 23, 2009, 2:08 PM
Post #22 of 22
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Registered: Oct 6, 2003
Posts: 35
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looks like a material imperfection located close to he weld. The material properties could have been changed more than they should have been by rapid quenching. The combination of a possible existing material flaw and a drastic change in the material properties combined with the play between the nose and the wire gate could cause a superficial crack to propagate into a visual crack. Considering the amount of bending caused every time the biner is loaded.
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