SS 304 vs 316 longevity

Hello all;

I've recently got into bolting and have a little crag I'm building out. I've read about the longevity benefits of using 316 SS over 304. I'm just curious if anyone has data or refrences to the actual longevity of 316 over 304...

Is 304 likely to last 30 - 40 years? 

As developers do we have an obligation to put material in thats likely to last 100+ years?

If the year is 2122 and people are still climbing routes I put up are they likely to have been rebolted multiple times by then anyway?

I want to develop in a responsible and ethical way, I don't have a problem shelling out cash for the highest possible quality, but if they're going to need to be rebolted in 50 years vs 110 years at what point is the SS quality no longer important...

It seems like a lot of developers in my region are using 316 so that's my intention to stay in line with the local ethic and standard, I'm just hoping to gain some insight from other developers and curious if there's any actual data or info on the expected longevity.

This probably isn’t helpful but there are routes here bolted with the same metal all the way, the corrosion can vary significantly based on seepage. I generally place 304 on steep overhangs that get almost no water and 316 the rest of the time.

Outside of coastal environments or some other weird corrosive environment, can someone point to a 304 bolt that needed replacement due to corrosion?

it isn't a question of longetivity, they both have equally long or short lives depending pn the conditions. The difference is their susceptibility to specific types of corrosiony, 316 being more resistant generally.

Normal steels have different corrosion rates depending on their grades, with stainless steel it's a question of whether it corrodes or not.

I agree with PPL and Jim: there are many types of climbing bolt corrosion that has been well documented.  

Oxidation, galvanic, SCC and most recently SSC due to sulfur reducing bacteria(!) are the usual culprits.   You can find pretty good descriptions of each type by searching here on MP (Darin).   Jim uses the word "conditions" and this encompasses climate, rock type, aspect, vegetation, proximity to the sea, etc.  

The Access Fund recommends 316 everywhere in the U.S. except near the coasts or other aggressively corrosive locations where Titanium is recommended.  

Dewalt Powers Rawl "5 piece bolts" are mostly 304 are still in common ussage for bolt replacement in the US. 

I started using them in NC and WV in 1990. Not exactly a desert climate.  None of those bolts show any sign of corrosion. 

You cant go wrong with 316 in most non coastal areas, but there are  plenty of examples of 304 working for long periods of time. 

I have  304 bolts placed over  20 years ago in vt that  look perfect. 

Nick Goldsmith wrote:

I have  304 bolts placed over  20 years ago in vt that  look perfect. 

And there are 90 year-old grandmothers out there who have smoked all their lives, too.  

John Byrnes wrote:

And there are 90 year-old grandmothers out there who have smoked all their lives, too.  

Not a valid comparison.  

Most of the 304 stainless bolts that have been placed in the North America will be just fine after 20 years.

Sure, some won't. The 90-yo smokers of the 304 stainless bolts are the ones that are still fine after 20 years in a sea coast, or, similar high-corrosion environment. Most, almost all, won't make it -- but a few, lucky, ones are still going to be around.

know what metal to use in your intended environment and medium.
Stainless almost always. Grade, circumstantial.
Titanium in marine environments is highly recommended.
Glue or mechanical?
Galvanized steel shouldn't be used for non replaceable hardware...and even then.

304 bolts are fine in MANY areas and will last very easily 20+ years.

It is facinating that modern 3/8” bolts are discussed “lasting 20+ years” as a benchmark of longevity. I think we should aspire for 50-100 avg. longevity. Obviously the conditions and amt of use will change the safe life span of of a bolt. However, I predict modern SS 3/8” bolts in arid environments will last much longer than the previous generation of bolts which were often not stainless and seem to still linger at crags, catching falls 30-40 years later.

In an arid environment is it reasonable to predict that a good 3/8” stainless bolt placed in say granite could support 50-100 years of safe use? This has been my assumption placing bolts in areas that do not experience high rates of corrosion or heavy use. 

There are stainless bolts installed in 1964 still climbed on in Germany, the cement is holding up well.

Like I  said  I  have placed  304 3/8ths bolts  20 years ago that look like they were  placed  yesterday.  Others have  lichen  growing on them but  otherwise look  fine.  The only  bolts I have placed in  water streaks  I  haven't  gone  back and  checked  in forever.  

Cole Lawrence wrote:

It is facinating that modern 3/8” bolts are discussed “lasting 20+ years” as a benchmark of longevity. I think we should aspire for 50-100 avg. longevity. Obviously the conditions and amt of use will change the safe life span of of a bolt. However, I predict modern SS 3/8” bolts in arid environments will last much longer than the previous generation of bolts which were often not stainless and seem to still linger at crags, catching falls 30-40 years later.

In an arid environment is it reasonable to predict that a good 3/8” stainless bolt placed in say granite could support 50-100 years of safe use? This has been my assumption placing bolts in areas that do not experience high rates of corrosion or heavy use. 

Stainless in the right environment will last 50-100 years for sure.

Mr Rogers wrote:

know what metal to use in your intended environment and medium.
Stainless almost always. Grade, circumstantial.
Titanium in marine environments is highly recommended.
Glue or mechanical?
Galvanized steel shouldn't be used for non replaceable hardware...and even then.

304 bolts are fine in MANY areas and will last very easily 20+ years.

All true, but having climbed for 40+ years, I have a much longer perspective.  I don't believe 20 years is anywhere near enough time.  When you're my age, are you going to go back and replace the bolts on your routes?  Who's gonna do it the second time?  If you've moved across the country, are you going to go back every 5 years to inspect the bolts and replace the ones that need it?

Having replaced many hundreds of bolts, I know that it's a lot of work, costs a lot of your own money and is not nearly as satisfying as putting up a new route.   So... in order to save a few bucks by putting in mechanical 304, you are (perhaps) condemning someone else to replacing them 20 years down the road, spending their time and money.  How do you justify that?   Or if no one replaces them and one breaks during a fall...

Most places don't need Titanium, but 316 is always better than 304, and a glue-in has many significant advantages over mechanical bolts.   Put in the best bolts you can, and then generations of climbers, not just one generation, will thank you.

John Byrnes wrote:

All true, but having climbed for 40+ years, I have a much longer perspective.  I don't believe 20 years is anywhere near enough time.  When you're my age, are you going to go back and replace the bolts on your routes?  Who's gonna do it the second time?  If you've moved across the country, are you going to go back every 5 years to inspect the bolts and replace the ones that need it?

Most places don't need Titanium, but 316 is always better than 304, and a glue-in has many significant advantages over mechanical bolts.   Put in the best bolts you can, and then generations of climbers, not just one generation, will thank you.

Thanks for your reply John.

I certainly appreciate you’re 40+ year perspective. This is exactly why I’m asking…

is there evidence or date that show 304 needing replacement after 20 years and 316 lasting 50-100?

What is the realistic difference in longevity?

How long can I expect a high quality 316 mechanical bolt to last?

How about a high quality 316 glue in?

Elijah S wrote:

Thanks for your reply John.

I certainly appreciate you’re 40+ year perspective. This is exactly why I’m asking…

is there evidence or date that show 304 needing replacement after 20 years and 316 lasting 50-100?

What is the realistic difference in longevity?

How long can I expect a high quality 316 mechanical bolt to last?

How about a high quality 316 glue in?

Was there something confusing about my post earlier?

It isn't a question of how long either lasts, it's a matter of will 304 or 316 corrode in the conditions in a particular area, if either does then their life may be measured in hours or days. 316 has a higher resistance than 304 which is why 304 is no longer used in Europe, either for climbing bolts or construction anchors.

Mechanical bolts are only considered acceptable for ten years in areas subject to freeze thaw so for much of Europe not popular.

John Byrnes wrote:

All true, but having climbed for 40+ years, I have a much longer perspective.  I don't believe 20 years is anywhere near enough time.  When you're my age, are you going to go back and replace the bolts on your routes?  Who's gonna do it the second time?  If you've moved across the country, are you going to go back every 5 years to inspect the bolts and replace the ones that need it?

Having replaced many hundreds of bolts, I know that it's a lot of work, costs a lot of your own money and is not nearly as satisfying as putting up a new route.   So... in order to save a few bucks by putting in mechanical 304, you are (perhaps) condemning someone else to replacing them 20 years down the road, spending their time and money.  How do you justify that?   Or if no one replaces them and one breaks during a fall...

Most places don't need Titanium, but 316 is always better than 304, and a glue-in has many significant advantages over mechanical bolts.   Put in the best bolts you can, and then generations of climbers, not just one generation, will thank you.

Notice I said very easily 20+ years. With the truth being likely being a multiple of that number.
304 in sierra granite will likely last the rest of my lifetime. That same 304 by the ocean will not. Know what materials to use for your particular medium and environment and you'll have "lifetime" anchors.

The main difference is that 316 is more resistant to chlorides than 304.  Since you're in the PNW, the question is if you're close enough to the ocean and what wind patterns exist for sodium chloride to reach your bolts.

Elijah S wrote:

Thanks for your reply John.

I certainly appreciate you’re 40+ year perspective. This is exactly why I’m asking…

is there evidence or date that show 304 needing replacement after 20 years and 316 lasting 50-100?

What is the realistic difference in longevity?

How long can I expect a high quality 316 mechanical bolt to last?

How about a high quality 316 glue in?

I think Jim addressed these issues: 316 will last longer than 304 in just about every application.  But it's much harder to quantify "long" and "longer" because there are so many factors, as has been listed above.   

Glue-ins outperform mechanical bolts in both longevity and strength and I like them much more than mechanical bolts in use. They're easier to clip and from all directions. They don't cut the carabiners on my project draws or the quick-links on fixed draws. Many of them have a big enough diameter and big enough hole to allow you to thread the rope and lower-off without leaving a biner at the crux clip (and totally fucking the next guy). The bolt and/or nut never get in the way, you never get spinners, they're not as noticeable, etc. So what I would use is a 316 glue in most inland areas.

Just for comparison, I've done most of my bolting with titanium glue-ins, now US$13.16 each plus shipping and duty, and using RE-500 at $50+ per packet.  The most expensive bolt and most expensive glue.  (So when I hear people whining about $6 bolts, I just shake my head.)    But when i asked a metallurgist how long they would last, his answer was "indefinitely".  Indefinitely is the word they use when they don't want to say "forever".   One and done.  They will never need to be replaced.

I'll gladly put in titanium everywhere if you're buying.
$15-18 a bolt is a bit cost prohibitive when you have a crag that will have 50+ lines in it at average 10 bolts a pitch.
Thats about $8K give or take.