Buffing 'biner burrs

[mick]

What's the best way to remove small burrs, like those caused by loading on a sport hanger, from the basket of a carabiner?

Would really high grade sandpaper do the trick? Is it a bad idea to try and fix them at all?

[chossmonkey]

What's the best way to remove small burrs, like those caused by loading on a sport hanger, from the basket of a carabiner?

Would really high grade sandpaper do the trick? Is it a bad idea to try and fix them at all?

Yeah, fine-ish grain sandpaper will work. I've used 220 to get some burs out of a locker once. If you have an old hunk of rope you could use the paper to get the big stuff then hang the biner and run the rope back and forth to buff the finer stuff out.

Why is it a concern? I wouldn't call it a bad idea, but it could be time consuming and will add more wear to your biner. Unless your partner screwed up and put one of your rope end biners on a bolt or something similar I personally wouldn't bother.

[Adam]

Why is it a concern? I wouldn't call it a bad idea, but it could be time consuming and will add more wear to your biner. Unless your partner screwed up and put one of your rope end biners on a bolt or something similar I personally wouldn't bother.

yah, once you've used a biner on a bolt, it should be dedicated to 'bolts only'. those burrs, if running against a rope, will shred the h3ll out the rope. you don't want that. if you follow this approach your ropes will last longer, you'll be safer, and you won't have to spend time sanding down burrs.

[Stan]

That's why they make biners in different colours
It should be noted: titanium and zicral alloys may develop micro-cracks over time.
Regular aluminium is more viscous, though.

[Adam]

That's why they make biners in different colours
It should be noted: titanium and zicral alloys may develop micro-cracks over time.
Regular aluminium is more viscous, though.

and generally speaking i use bent-gate biners for rope end and straight gates for clipping bolts. helps keep them separated as well.

can i see a reference on the titanium/zicral thing? wouldn't that be a reason to not use titanium bolts along the coast?

[betaburgler]

All metals can develop "micro-cracks" over time:

- It can be caused by fatigue which is cracking due to the cyclic (repetitive) loading of the material over time (millions of cycles). The stresses involved in fatigue cracking can be much less then the materials "yield" strength, or the force required to permanently deform the metal.

- Corrosion can promote cracking in several ways. Not going to get into this one, just taking care of your equipment helps prevent corrosion issues.

- Impact loading, or fretting (rubbing wear), material defects can all present points for cracks to form. Inspect your gear for damage and throw that biner you dropped from the top of that pitch away.

Zicral is actually a 7000 series aluminum alloy (7075). From what I've read 7000 series aluminum is what biner manufacturers commonly use. The primary alloying element is zinc. Zinc is added to improve the strength of the aluminum, but typically where strength is improved ductility is lost. Zicral is used for its strength to weight ratio.

A little about strength vs ductility: Strength is good when you fall on your biner taking a 25 ft whipper. You don't want the thing to break, and it would be nice if it were able to deform, absorbing the energy of the impact, but "bounce" back afterward. This is the ability of the metal to deform elastically. Brittle materials lack this ability, and it is an important part of why metals rock.
Ductility is the metals ability to plasticly deform. In other words how far it will bend before it breaks. This is a good quality to have in a biner because it gives you some warning before the thing breaks completely, and absorbs energy as its deforming. This is where the cracking comes in (at least in the context of this post). A less ductile material will be more likely to form cracks in order to absorb energy. Cracks are bad because they make stuff break so ductility must be pretty good.

Titanium and its alloys are typically less ductile then aluminum and its alloys (there is cross-over however as the two have many alloys). Titanium alloys used in biners are typically more corrosion resistant then aluminum alloys such as Zicral. Just choose your tools properly for the environment you are in.

[mick]

The biners got burred because I set up a slackline on hangers at the Rock Court with them.

Stupid, I know, but I didn't think that it would wreck them at the time. Since then I've bought a few cheapo biners to dedicate to slacklining, but I was hoping to buff the burrs out of my nice Petzl Attache lockers and use them for body weight only climbing applications like attaching a daisy chain to an anchor or maybe even rappelling. They won't be used for setting an anchor or belaying a leader, but I can't bring myself to toss them.

Thanks for the metallurgical coles notes, Professor Benjamin

[chossmonkey]

The biners got burred because I set up a slackline on hangers at the Rock Court with them.

Stupid, I know, but I didn't think that it would wreck them at the time. Since then I've bought a few cheapo biners to dedicate to slacklining, but I was hoping to buff the burrs out of my nice Petzl Attache lockers and use them for body weight only climbing applications like attaching a daisy chain to an anchor or maybe even rappelling. They won't be used for setting an anchor or belaying a leader, but I can't bring myself to toss them.

Thanks for the metallurgical coles notes, Professor Benjamin

If you have doubts about your gear you shouldn't use it for anything. Its too easy for them to end up in a spot where it does matter.

That said, the biner is probably fine. I'd probably still use it.

[betaburgler]

Thanks for the metallurgical coles notes, Professor Benjamin

Wow I'm impressed you not only remember the word metallurgical but even spelled it correctly!

I might as well share some of the knowledge it cost me 50 grand to cram into my head.