Ascender Safety 101

       Ascending Rappel Ropes 101

       Autoblock Misuse (ATC-Guide)

       Avalanche Safety

       Belay School - Why Dynamic Matters

       Can A Hot Belay Device Melt My Slings?

       Carabiner Off-Axis and Tri/Quad-Axial Loading

       Choosing the Right Carabiner

       Common Belay Screw-ups

       Connecting Two Slings Together

       Daisy Chain Dangers

       Dangers of Rope Worn Carabiners

       Dangers of Worn Lowering Anchors

       Do Ropes Need to Rest Between Falls

       Draws in a Gym

       Extending a Cam Sling

       Fall Factors Explained

       Full Strength Haul Loops

       Gear Doesn't Last Forever—Crampons

       Gear Doesn't Last Forever—Ice Tool Picks

       Gear Doesn't Last Forever—Slings & Draws

       Girth Hitching a Stopper

       How Sketchy Is a Sharp-Edged Carabiner?

       How Strong are Himalayan Fixed Lines?

       How Strong is the Spinner Leash?

       How To Belay, Part 1

       How To Extend a Rappel Device

       Knot Passing 101

       Rappelling - Climbing's Diciest Business

       Re-Slinging Cams

       Rethinking the Double-Loop Bowline

       Retiring Old Ropes

       Sharpie for Marking the Middle of a Rope?

       Sling Strength In Three Anchor Configurations

       Spectra versus Nylon

       Spotting for Bouldering

       Surviving Bad Weather on El Cap

       The Dangers of Modifying Your Gear

       The Dangers of Short Static Falls

       The Electric Harness Acid Test

       The Skinny on Super Light Ropes

       Top Roping is Not So Safe

       To Screamer Or Not To Screamer

       Via Ferrata

       Weakness of Nose-hooked Carabiners

       What is the Safest Rappel Knot?

       Worn Belay Loops and Retiring a Harness

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Climb Safe: Re-Slinging Cams

22-May-2017
By Kolin Powick

The following article is courtesy of Black Diamond Equipment.

A cam sling in need of replacement. I get a lot of emails about re-slinging cams:

  • Do I really need to send my Camalots and C3s into BD to have them re-slung?
  • Can I re-sling them by myself?
  • Can I have someone with a bartackers re-sling my cams?
  • Is it ok to use a piece of nylon with a knot? What about Spectra/Dyneema?
  • Will you re-sling non-BD cams?
  • Why does BD use that weird sew job on the C3s and Camalots and not just use a single loop of webbing?
  • Many companies are now using 10mm Dyneema or Spectra; why don't you guys do that? And can I re-sling mine with 10mm?
  • Many companies use double length slings, can I re-sling my Camalots this way?

Yowsa! And it goes on and on...

Here's the low-down on re-slinging cams from the QC Lab perspective:

 

GENERAL

Contrary to popular belief, climbing gear does not last forever. Plastics and textiles aren't as durable as metals, and need to be inspected and possibly replaced more often. Check your cam slings, and if they look beat, send them off for replacement—preferably to the manufacturer. General guidelines for replacing slings on cams are as follows:

  • With occasional use: slings should be replaced every 5-8 years
  • With frequent use: slings should be replaced 2-5 years.

Of course, these are just guidelines. A brand new cam sling could get dusted after one pitch if the sling ran over a razorblade granite edge and got sawed back and forth while jugging or something. Remember it's every individual climber's responsibility to check their gear often, and when it doubt, throw it out.

 

CAMALOT AND C3 SLING DESIGN

Camalot thumb loop under load. The previous generation of BD Camalots had a cast stainless steel tailpiece. There was a nice big surface area with a smooth radius. The webbing went through this and was sewn in a single loop. When we redesigned the Camalots in 2004 we wanted to make them lighter and also allow more surgically precise when placing. Hence was born the current thumb loop. One of the challenges came when adding the sling to the mix. The deformation of the thumb loop under load is significant. I dug up the following photos from when we were developing the new Camalots.

Just sewing a loop of 11/16" SuperTape (as was used before) didn't get us to where we wanted to be strength-wise. Why? Because when the Camalot was loaded during testing, the cable pinches down, and ultimately cut the webbing at loads less than we were happy with (gunnin' for 14 kN but only getting about 10 kN). Same with similar-width Spectra.

We also noticed that during drop testing, the cabled thumb loop would get tweaked under standard Indian Creek whipper-type loads. And no one wants to throw down significant dough on a brand new cam only to have the thumb loop formed into a "V" after just a few lobbers.

During ultimate testing, the cable pinches and cuts a single layer of webbing (Spectra in this case). A double layer Camalot sling doesn’t cut under ultimate strength testing. So we determined that having the double layer of webbing was substantial enough to get us the strength we were after, didn't cut the webbing and produced less tweakability (engineering term) of the thumb loop.

Tweaked vs. non-tweaked thumb loop after similar falls (loads). And for those wondering, yes, we also experimented with the extendable sling design and found that when the sling is extended the cams not only failed at lower loads, but the thumb loop was damaged more easily.

Basically, in all cases the perceived benefits were outweighed by our strength and durability requirements, therefore we went with the sling configuration you see on the current Black Diamond Camalot line. 

 

RE-SLINGING BLACK DIAMOND CAMALOTS AND C3S

So what and how should you re-sling your BD cams? Of course you can do anything you like:

  • One-inch tubular webbing with a knot will work.
  • Sending them to someone that knows how to sew structural climbing gear, and have them bartack a single loop of SuperTape will work.
  • Having someone that knows what they're doing bartack a double length of SuperTape or 10 mm Dynex will work.

Double-layer sling configuration shown on current BD Camalots.But it's important that you understand the ramifications of such methods:

  • The strength will be compromised in all cases.
  • The thumb loop will get tweaked much easier in all cases.
  • BD doesn't warrant any modifications to the design of our products.

And note:

  • Dyneema/Spectra doesn't hold a knot. Never use a knot with Dyneema/Spectra.
  • And when it comes to sewing any structural climbing gear, mom's sewing machine won't cut it. Be sure to go to a shop that has experience with CLIMBING gear and knows what they're doing.

 

BOTTOM LINE
  • Check your gear often. If it's worn out, replace or repair it.
  • BD Camalot slings are sewn the way they are for several reasons—don't change it.
  • It's always best to contact the original equipment manufacturer of any product to ask for recommendations on the most appropriate way for repair.

We offer trigger wire repair and sling replacement on Black Diamond cams: $15 for trigger wires and $8 for new slings. More information here:

BLACK DIAMOND CAM REPAIR

I hope that helps explain some of the common questions when it comes to replacing slings on cams.

Whip away,
KP

 

 


Kolin Powick (KP) is a mechanical engineer hailing from Calgary, Canada. He has over 20 years of experience in the engineering field and served as Black Diamond’s Director of Quality for over 11 years. He is currently their Climbing Category Director. If you have a technical question for KP, please email him at askkp@bdel.com and he will TRY to respond.

To help make more climbers safer climbers, Rock and Ice has teamed up with Black Diamond Equipment to present the information here.

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