Mixed Metals
- Thread starter Eric_E
- Start date
- Location
- Asheville,NC
Not a big deal if you don't leave them together for a long time. If it was a bolt(steel) with and alumninum washer a chemical reaction would occurr. I think they swap molecules or something resulting in weakness. More a long term issue then short term.
- Location
- Retired in Minneapolis
This explains the process:
http://www.engineersedge.com/galvanic_capatability.htm
Over the years this topic has come up for discussion a few times. The basis for the concern seems to be that the tougher metal [steel] will pound on the softer metal [aluminum] and deform it to the point of failure. Sure, that's possible but unlikely if even a casual inspection is done. Way before the strength is compromised the gear will look beatup and would be retired. I've seen stainless steel rescue pulleys that were rigged with steel biners that had the cheek plates all twisted and bent because they were overloaded. More of a loading issue than metallurgy.
When ever possible I try to have a soft link between biners/shackles or other hard links. Sometimes this isn't practical or the best configuration though. Cross loading the biner is a bigger concern.
http://www.engineersedge.com/galvanic_capatability.htm
Over the years this topic has come up for discussion a few times. The basis for the concern seems to be that the tougher metal [steel] will pound on the softer metal [aluminum] and deform it to the point of failure. Sure, that's possible but unlikely if even a casual inspection is done. Way before the strength is compromised the gear will look beatup and would be retired. I've seen stainless steel rescue pulleys that were rigged with steel biners that had the cheek plates all twisted and bent because they were overloaded. More of a loading issue than metallurgy.
When ever possible I try to have a soft link between biners/shackles or other hard links. Sometimes this isn't practical or the best configuration though. Cross loading the biner is a bigger concern.
- Location
- Hawaii
This brings up a different point, and I don't mean to derail the thread... but was wondering if there was a certain DOE (date of expiration) you guys put on a lot of your gear. Meaning, regardless of whether the gear "appears" to be extremely worn, if it has been in daily use for such and such a time, it automatically gets retired?
jp
jp
- Location
- Longmont, CO
[ QUOTE ]
This brings up a different point, and I don't mean to derail the thread... but was wondering if there was a certain DOE (date of expiration) you guys put on a lot of your gear. Meaning, regardless of whether the gear "appears" to be extremely worn, if it has been in daily use for such and such a time, it automatically gets retired?
jp
[/ QUOTE ]
You're right J.P. it is a different thread, but I wonder the same thing. I did find this atricle though.
Climbing Gear Care
I have been using the same 2 Petzl ball locks on my lanyard for 4 years now. I think it is time to retire them.
This brings up a different point, and I don't mean to derail the thread... but was wondering if there was a certain DOE (date of expiration) you guys put on a lot of your gear. Meaning, regardless of whether the gear "appears" to be extremely worn, if it has been in daily use for such and such a time, it automatically gets retired?
jp
[/ QUOTE ]
You're right J.P. it is a different thread, but I wonder the same thing. I did find this atricle though.
Climbing Gear Care
I have been using the same 2 Petzl ball locks on my lanyard for 4 years now. I think it is time to retire them.
- Location
- Longmont, CO
I avoid mixing metals too. I personally don't like it. Sounds like good practice.
