Aluminum Chain

Not a developer in any way so don't get too riled about this actually happening, just curious about this thought I had while drifting off to sleep.

Specifically for crags/climbs with a longer hike in or many pitches of climbing before arriving at the anchor location, why don't those who equip chains on these routes use aluminum chain with a steel quicklink on the end?

I'm specifically thinking of desert towers with a bit of a hike in, and other formations where the rap bolts need to be extended over an edge for rope retrieval purposes. Webbing is the classic answer to this scenario since its light to hike in and easy to vary the length of, but its not a very sustainable solution due to the high amount of UV exposure on the top of towers, and it ends up having to get replaced frequently, generating more waste. Steel chains are the upgraded and far more sustainable option, but they're heavy to pack out and drag up a climb that might not see enough ascents to feel "worth it". 

Therefore, I'm curious why I haven't encountered something like a 10mm aluminum quicklink attached to the hangars, then an appropriate length of 10mm aluminum chain (i suppose it could be skinnier but 10mm seems reassuringly beefy), then an 8 or 10mm steel quicklink on the rope end of the chain for replacability and extended wear characteristics.

Lets start off with talking about specifically in backcountry desert environments,  but I am also interested in the applicability of this system in backcountry areas that recieve more moisture, but aren't seaside/on rock with minerals that could act as an electrolyte/catalyst for galvanic corrosion. Is aluminum chain too difficult/expensive to source? More so than stainless chain? Are there concerns with galvanic corrosion with aluminum between either stainless steel or plated? (I saw mixed reviews on the actual likelyhood of this with a quick google) Other things that I'm not thinking of? 

I have seen steel chain whipped around by the wind carving grooves in the rock over time.  I would imagine aluminum chain would be even worse but instead of the rock getting worn the chain would (as well as the rock) at an accelerated rate, like maybe less than a season in a windy area.  

I've never heard of load rated aluminum chain,  even if you were able to source it as a specialty item it would surely be very expensive.  

Having seen aluminum carabiners nearly disintegrated, corrosion can definitely be an issue with permanently placed aluminum. Besides the environment, the alloy and quality of anodinization would likely play a big factor in how quickly this happens.  An aluminum carabiner between the hanger and chain can quickly get notched, especially by certain brands of hangers with sharp edges like the fixe one in particular.  Aluminum hangers were out in the wild for awhile and were a resounding failure. 

Not every route needs chains,  especially if people are just rappelling off it a quicklink and a steel ring typically work fine with minimal twisting, especially if the wall is a relatively flat surface.  If twisting becomes an issue,  vertically spaced bolts instead of horizontal are an easy fix.  

If chain is necessary,  a quality 5/16" SS chain really isn't that heavy and plenty strong enough for any climbing application.  

plastic chain would even be lighter! and you can get it a bunch of cool colors.  ;)

Finding aluminum chain is the first problem.

Thanks for the replies yall.

https://www.mountainproject.com/photo/118890642

A classic kong aluminum hanger photo

Yeah I certainly get the inherent limitations of aluminum hangars, but 10mm aluminum chain is substantially thicker and in my proposed application, would essentially just be webbing that isn't affected by UV exposure 

It's hard to get solid numbers because aluminum chain doesn't seem that common, but I found this. It's 5/16" instead of 10mm, but it has a breaking strength of 15kN which is on par with 1" webbing. So then it's a contender for lightest chain option, but then I found this, stainless steel chain with the same breaking strength, 78% of the weight, and a third the price. So that right there is your reason to not use aluminum chain. Admittedly the aluminum chain is 5000 series vs the stronger 7000 series used in most climbing gear, but 5000 series is more corrosion resistant and most 7000 series aluminums aren't even weldable.

If you want something with more longevity then nylon webbing, but lighter than steel chain, there are other textiles with better UV resistance then nylon.

Wow that is some seriously skinny stainless chain with quite elongated links! Thanks for the info, are any of those other textiles with better UV resistance available in a convenient form (such as webbing or cord) without being prohibitively expensive?

Ben Mwrote:

Wow that is some seriously skinny stainless chain with quite elongated links! Thanks for the info, are any of those other textiles with better UV resistance available in a convenient form (such as webbing or cord) without being prohibitively expensive?

How long do you think it would last before someone cut it off and replaced it with nylon because they didn’t know it was superior and best practice is to use your own material?

Smaller version of this might do it:

https://youtu.be/yFZkXay0wZM

Rachael v2wrote:

How long do you think it would last before someone cut it off and replaced it with nylon because they didn’t know it was superior and best practice is to use your own material?

This X1000!

The lightest alternative would be Stainless cable. But that would be more easily implemented by the developer,  not after the fact. In most situations chain is simply not necessary for anchors that are only getting rappelled on. 

Rachael v2wrote:

How long do you think it would last before someone cut it off and replaced it with nylon because they didn’t know it was superior and best practice is to use your own material?

Exactly,

I spent a bunch of time treading cord into tubular (the tubular webbing being a sacrificial uv sheath of sorts) to replace the tatapuses on a remote route only to have some good samaritan comment a couple months later that they replaced all the webbing...