5mm cord, Is it safe for anchor setups?

Good god. If you have to ask, you've already answered your question.

8mm.

Dan Bachen wrote:Just finished Climbing Anchors second edition and it really made me rethink using static chord like 5mm dyema or similar. The book made a case that the flexibility of nylon decreases peak forces while static chord just transfers it. Would highly recommend the book to anyone who climbs gear, it made me change some of my go-to setups.

With one notable exception. The quad setup tied with 5mm tech cord is a great setup for bolted anchors.

Ryan Williams wrote:I usually use the rope but when I carry a cordelette it's a 7mm nylon chord. I suppose you could use spectra/dyneema and a thinner cord but I've never enjoyed tying knots in that stuff. I don't think I'd want to use a 5 mil nylon cord for an anchor and I don't think it's designed for that. Typically I use 5 mm cord for a prusik or anything that will take a static load only. Like the attachment cord for a haul bag for example. But an anchor should be beefy, and able to withstand a catastrophic event such as a big factor two fall. For this I think you need AT LEAST 6 mil and preferably 7. The anchor is the only thing keeping you and your partner from going splat. This is precisely why I like to use the rope. It's dynamic, and it is designed to catch giant falls and withstand huge forces. Why not use the strongest piece of gear you own for your anchor?

im a big fan of the rope too. i dont get too many full rope length climbs anyway. so theres no extra gear to carry, and i wont have any worries at all bout it being strong enough. but if im somewhere where i might need as much rope as posible, the sure ill carry the cordalette. i think mines a 7mil, but it rarely sees the crags.

Although lighter and smaller, is it REALLY worth changing? Not to mention since it incorporates dyneema/other synthetics, it does not stretch like nylon. Its similar to building an anchor out of a dynex sling; doable, but not suggested because its relatively static.

DannyUncanny wrote: Assuming that you somehow built an anchor which put all of the weight on a single unknotted strand. Most people double the load rating and subtract a bit for knots when using material for anchors because you should always have at least two strands taking whatever the load is.

+1 If you have three pieces of gear you end up with 6 strands. If I'm thinking right that should be 6X the strength of a single strand. I use 6ml and find it perfect.

Dan Hall wrote: With one notable exception. The quad setup tied with 5mm tech cord is a great setup for bolted anchors.

Agree.

Ty Harlacker wrote: +1 That's the working strength as well; breaking is probably double that.

-1. Spec strength for cord is MBS, _NOT_ SWL. Kindly refrain from spreading this incorrect information further.

Aric Datesman wrote: -1. Spec strength for cord is MBS, _NOT_ SWL. Kindly refrain from spreading this incorrect information further.

Thanks for letting me know, I appreciate it.

John Wilder wrote: you mean instead of two draws or the super-8? doubt it.

Self equalizing, redundant, bombproof, already tied and ready to go.

With proper configuration & normal situations it is probably fine. However when rigging that type of anchor I use & would recommend 7 mil cord to be sure.

For multipitch with bolted belays I prefer using the rope.

Bolted anchors a double length dynema sling tied to a master point is how I roll. for trad anchors a 15 foot peice of webbing to you guest it a master point has kept me feeling just fine. Maybe I am stupid or reckless but I have never felt unsafe with these set ups. And that's for single or multiple pitch.

is this set up safe with the 5mm?
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using the rope as anchors only works if you're switching leads right? i'm planning to do some multipitch but will be leader most of the time.

Johnny Ink wrote:is this set up safe with the 5mm?

if you've tripled it what's the point? My rabbit runner is way smaller than that.

I've been using these

bentgate.com/raru4ftbyya.html

in 10' and 12' lengths and they're great. Strong, fast, and small, could do the same thing with a piece of cord though.

Johnny Ink wrote:using the rope as anchors only works if you're switching leads right?

Wrong. You might want to practice this (basic) technique before taking your friends out.

Aric Datesman wrote:Do you build anchors with single strands of cord, Matt? If not, you might want to rethink those numbers. That's not to say I don't agree with you, just that you've forgotten to take into account that the arms of the anchor are typically loops.

pretty sure just because there is a single loop on the leg doesnt make the tension on the rope any different (unless you made each side independent with a clove hitch or something). little experiment you may want to try with fishing line: 10 lbs test + 15 lbs weight. Tie the line directly to the weight and slowly lift (SNAP). Make a single loop around the weight and lift (SNAP). Im no expert but...pretty sure a single loop doesnt increase the strength at all.

Brendan Blanchard wrote:Not to mention since it incorporates dyneema/other synthetics, it does not stretch like nylon. Its similar to building an anchor out of a dynex sling; doable, but not suggested because its relatively static.

For everyone suggesting you not build multipitch anchors with static materials, what are you leading on, steel cable? It's perfectly fine to build anchors with dyneema. Your body, the rope, the movement of the belayer, and movement of the rope thru the belay device all absorb forces in a fall.

As for 5 mil cord I'd be wary. It will wear out faster, cut easier, and the margin of safety is far less than with burlier cord. The cost difference and minimal weight difference just aren't enough to make it worth it in my opinion. Spend the $10 bucks and get some new cord. You and your partners will feel better.

Johnny Ink wrote:is this set up safe with the 5mm?

In a pinch Id use it.... It wouldnt be my first choice however. Its strong, but thinner with abrasion fails much easier too... doubled and fig 8, its pretty much bomber...

Holy Lazarus thread Batman. Get some 8mm cord already. Or go for the 7mm if you are "Fast and Light" like the cool kids. You could probably shave that wieght by taking a nice crap before sending.

No, 5mm cord is not safe. Will it definitely fail? Who want to be the first to find out?