|
bspisak
Sep 19, 2002, 4:38 PM
Post #1 of 11
(1636 views)
Shortcut
Registered: Sep 18, 2002
Posts: 74
|
Any opinions on whether or not using punch type stamps to mark your carabiners is safe for the gear or not? Much more permanent than tape, but could it create stress fractures? Any metalurgists out there? Technical opinions only please!
|
|
|
|
|
rockprodigy
Sep 19, 2002, 4:49 PM
Post #2 of 11
(1636 views)
Shortcut
Registered: Sep 10, 2002
Posts: 1540
|
Any depression in a amooth surface will create a stress concentration, however, the severity of the stress concentration depends on the size of the depression relative to the size of the material you are stamping into. The smaller the material, the smaller your stamp needs to be. Many of the manufacturers themselves stamp gear, so it can't be all bad. Stamping gear yourself will probably be OK, if you pick the right place to do it. The best thing would be to find non-structural parts to stamp. Failing that, Objects which see a compressive load are better than those in tension because fatigue cracking is a result of repeated tensile loading.
Personally, I'd use paint.
|
|
|
|
|
rockhanger
Sep 19, 2002, 4:49 PM
Post #3 of 11
(1636 views)
Shortcut
Registered: May 29, 2002
Posts: 7
|
Straight out, DON'T DO IT!! You mention carabiners, which are generally made from alloy 7075 in the "T-6" condition. In this condition the micorstructure will not accept any forming without developing stress fractures. Even the slightest indentation could create stress risers that when loaded focus the stress to theses areas causing a premature fracture.
The only acceptable methods for marking are those that do not alter the structure or exposed the aluminum to any chemicals.
Altering gear in any manner is asking for trouble.
Just my opinion.
Rock
|
|
|
|
|
rockhanger
Sep 19, 2002, 4:58 PM
Post #4 of 11
(1636 views)
Shortcut
Registered: May 29, 2002
Posts: 7
|
A note regarding "Rockpridigy's" response. Manufacturers do forming in a soft condition, "O-temper". The material is maleable (formable)in this condtion. Any stamping is done at this stage and then the final product is heat treated for strength. This puts the material in a condition where it cannot be formed futher.
Basicaly don't $%%^& with something you don't understand. Your advice, on this topic, could get someone killed.
Rock
[ This Message was edited by: rockhanger on 2002-09-19 10:01 ]
|
|
|
|
|
wlderdude
Sep 19, 2002, 5:06 PM
Post #5 of 11
(1636 views)
Shortcut
Registered: Aug 8, 2002
Posts: 1123
|
I am by no means a professional metalurgist, but I have taken a few classes. But what really lets me say this with confidence is that I worked in a welding shop for a few years building and fixing all kinds of aluminum and steel parts.
Any sharp slit, tear, crack or otherwise WILL seversely weaken the biner. When the manufactutrer makes the biners, all the edges are made smooth trough a tumbling process to make sure that the surfaces don't have any sarp nicks in them. Aluminum really tears quite easily under heavy and especially cyclical loads.
Here is an experiment. Thake a potatoe chip bag and try and tear it open without a slit. Now put the samllest slit you possibly can and tear it right open.
It is kind of cool to see a weld break in half on an aluminum weld as it cools because you left the end with a thin, microscopic unfilled crack. If you can't see it, you will see it back soon as cyclical forces (even thermal cyling) make the crack run.
Steel can do the same thing, but ralely does. Usually, only heavy equiptment like dump trucks and bulldozers have problems with thin cracks running.
And to be honest, engravings in aluminum are hard to see. Just use heat shrinkable tubing, tape, rubber bands or nail polish. The brighter the better.
[ This Message was edited by: wlderdude on 2002-09-19 10:14 ]
|
|
|
|
|
rockprodigy
Sep 19, 2002, 5:59 PM
Post #6 of 11
(1636 views)
Shortcut
Registered: Sep 10, 2002
Posts: 1540
|
Rockhanger, You may be right about forming in the soft condition...I didn't think about that. However, not all manufacturing is done that way. I don't work in the climbing industry, so I'm not sure how they manufacture stuff. I do work in the aircraft industry, and there are certain parts that require cutting and forming to be done after heat treating to benefit from work hardening...anyways, that is probably not relevant to this discussion.
My final point, where I said "personally, I'd use paint" was meant to suggest that unless you are the engineer that designed the part, there's no way to know if it's safe or not to stamp them.
|
|
|
|
|
dsafanda
Sep 19, 2002, 6:06 PM
Post #7 of 11
(1636 views)
Shortcut
Registered: Mar 6, 2002
Posts: 1025
|
I have a couple of friends who have stamped intitials on their biners. One of them did some research and visited a biner manufacturer(Metolious...I think). He explained to them what he had in mind. He was assured that there was no way this could harm the biner in any way.
This ofcoarse is all second hand information. Take it for what it's worth, but personally I have no reservation at all about clipping in to these biners a thoulsand feet off the deck. I have many times.
[ This Message was edited by: dsafanda on 2002-09-19 11:13 ]
|
|
|
|
|
joebuzz
Sep 19, 2002, 6:18 PM
Post #8 of 11
(1636 views)
Shortcut
Registered: Aug 5, 2002
Posts: 107
|
It looks like I stand alone here. I did dyestamp all of my gear maybe 8-10 yrs ago. Since then it has seen TONS of use in every condition. It's all still working great.
I'm not suggesting anyone else do this, just a little beta.
|
|
|
|
|
mugnyte
Sep 19, 2002, 8:34 PM
Post #9 of 11
(1636 views)
Shortcut
Registered: Jun 8, 2002
Posts: 78
|
Why bother? Is paint/tape really not working? Do you share your gear that often with that many people?
Stamping seems akin to writing your name on your underwear.
|
|
|
|
|
moun10man
Sep 23, 2002, 3:54 AM
Post #10 of 11
(1636 views)
Shortcut
Registered: Sep 21, 2002
Posts: 39
|
paint or tape man!
|
|
|
|
|
knotrocket
Sep 23, 2002, 3:33 PM
Post #11 of 11
(1636 views)
Shortcut
Registered: May 26, 2002
Posts: 64
|
Just took a rope rescue course a coupla weeks ago, and kinda got in the same discussion. Mainly because you might have a multi-agency response with a lot of different gear around, or just different gear from another rescue company.
But anyway, not that sport climbing gear will likely see the loads inflicted on this gear, but our instructor was saying that strength tests of gear show that structural failure occurs right where it was engraved/stamped.
Food for thought...
|
|
|
|
|
|
