Using gear to build top rope anchors

Say I want to use gear (cams/ nuts) to build a top rope anchor because of a lack of trees.

Will my regular cordelette anchor with 3 pieces be satisfactory? Or should I do more? I’ve seen people use two cordellettes with 6 or more pieces, but I’m not sure if this is necessary.

Obviously every situation is a judgement call, but I was just looking for opinions from people who top rope on gear anchors often. Thanks!

If you've got 3 solid pieces and connect them in a way that is redundant and won't cause catastrophic failure even if a strand or 2 of cord/webbing get cut then you're good to go. 3 solid pieces is more than enough to create a bomber TR anchor. Keep in mind the magnitude of forces that might be generated in normal TRing, they're pretty low. 

You don't need to go overboard (whatever that means for you,) but don't cut corners and accept gear that's less than incredible. It's not like your butt is going to pump out as you scootch around and look for good placements.

My biggest concern is repeated loading cycles, which can saw through your cord if it's hanging over an edge.  I'll sometimes add a connection (like a sling) with an inch or two of slack as a backup in case the loaded cord breaks.  Three cams is usually plenty.  I avoid passive pro because it's harder to get out after being weighted a bunch.

Thanks guys I appreciate all your responses 

I'm bothered by the whole question. A TR anchor sees far less loading than a multipitch gear anchor could potentially be subject to. If the OP has that latter situation mastered, the TR side of it would be a non-issue. (If he doesn't, maybe he shouldn't be referring to his "regular anchor".)  My fear is that he's going to go out and build a 3-piece cordelette anchor 10 feet back from the lip - because mountain project said it'd be adequate - and proceed to shred his rope. I would prefer him to be focused on TR-specific concerns: securing himself while he builds the anchor, assessing/addressing anchor abrasion at the lip, and learning alternatives to his "regular anchor" for those many situations that require a TR anchor built on widely spaced placements.

Gunkiemike wrote: I'm bothered by the whole question. A TR anchor sees far less loading than a multipitch gear anchor could potentially be subject to. If the OP has that latter situation mastered, the TR side of it would be a non-issue. (If he doesn't, maybe he shouldn't be referring to his "regular anchor".)  My fear is that he's going to go out and build a 3-piece cordelette anchor 10 feet back from the lip - because mountain project said it'd be adequate - and proceed to shred his rope. I would prefer him to be focused on TR-specific concerns: securing himself while he builds the anchor, assessing/addressing anchor abrasion at the lip, and learning alternatives to his "regular anchor" for those many situations that require a TR anchor built on widely spaced placements.

Hey man I appreciate the concern!

I’m very comfortable with top rope anchors and have been building them for a while, and i am aware of that you shouldn’t have rope running over an edge. 
The thing is I always used trees with static line because trees were always available.
My question now is, if I could use only gear, how many pieces of gear is appropriate? The reason I ask is because I’ve seen lots of variation ranging from the general 3 piece joined with a cordelette, to like 6 pieces joined with two cordelettes. 

Hire a guide for a half day and have all your questions answered.

The short answer is yes, that's fine. But it assumes you're getting good placements in solid rock, arranging them appropriately with no crazy angles, rigging it well, not loading any carabiners over edges, handling any abrasion points where the anchor cord can rub from cyclic loading, and making every part redundant.  

That you're asking this question makes most of us assume you don't have experience with the first and mosy important item... identifying good placements.

For a top managed belay, my concern for abrasion and redundancy are much less because I'm there monitoring what's happening and usually not loading the anchor much. I don't mind using a skinny cordolette and a single locker for a redirect at the master point then

When it's an unattended anchor though, with repeated falls and lowers, I want thicker more abrasion resistant cord, padded edges, and 2 lockers on my redirect.

The rule I always go with on any anchor is three pieces that add up to 32kn.  If you have smaller pieces of pro you may need more than three pieces to get to 32kn.

32 is pretty excessive...I’ve heard 20 thrown out there and would be totally fine.  It’s important to remember that anchors don’t actually work that way, though so I would prefer 3 rock solid pieces to 8 marginal ones.  You should feel comfortable TRing on any individual piece, as that can sometimes effectively happen if your anchor shifts.

Also agree with Gunkie’s argument.  Multipitch anchors need to be able to hold a leader fall onto the anchor, which is a much higher force than anything a TR anchor will see.  If it’s good enough for that, it’s sufficiently overbuilt for TRing, just watch your soft goods and biners loaded over edges.

You don't want to have to worry. Three absolutely bomber pieces is sufficient, but they better be bomber. Assume anything smaller than a bd .5 isn't bomber under any circumstances for this purpose unless it's deadended in a constriction.

adeadhead wrote:...Assume anything smaller than a bd .5 isn't bomber under any circumstances for this purpose unless it's deadended in a constriction.

While I agree with the idea you're getting at... to try and avoid building anchors from micro gear; which has lower overall strength to the piece and less tolerance for error, walking, shifting rock, etc... drawing a line at BD 0.5 and saying never use them unless locked in a constriction I think is a bit too rigid.  I  dont get concerned till im resorting to smaller than bd 0.3 / metolious #1.  Those are still 8kn pieces.  Use the best placements available.

Don't use your cordellete. Use the same static rope you're using with trees, but just use it with gear.

​https://www.youtube.com/watch?v=-mXPDDhuaSQ​​​

All good advice. Two things I make a note of when building gear TR

1. Each lap or so have a look at it make sure nothing is getting tipped out, if I can’t see it I don’t blindly trust it.

2. Consider the fall line, maybe the route starts 5-10 feet left of where the route finishes, place cams appropriately.

3. I’m typical happy with 4 well placed larger pieces, 7mm, two large lockers opposite/opposed.

Don't forget the boat anchor.  This video will show you the way. 
https://www.youtube.com/watch?v=LM_2Q_JPX8E

When I make a TR anchor with gear I use the same big 9 mm static rope I use to tie to trees and boulders. I use four pieces of gear. I tie a bunny ears knot on two pieces and adjust the knot to equalize them then the same on the other end of the rope to two pieces of gear. Then I make a BFK knot for my master point with opposed lockers. This works most of the time.

AaronP wrote: All good advice. Two things I make a note of when building gear TR

1. Each lap or so have a look at it make sure nothing is getting tipped out, if I can’t see it I don’t blindly trust it.

2. Consider the fall line, maybe the route starts 5-10 feet left of where the route finishes, place cams appropriately.

3. I’m typical happy with 4 well placed larger pieces, 7mm, two large lockers opposite/opposed.

I see three...

Anyways, how/why would one place cams any differently in scenario #2?