FBinNY 

I've never attacked you, nor your credentials. FWIW I'm someone who cares about the message, not the messenger.

What I have done is dispute some of what you post as fact. Earlier, you insisted that there is no plate stress from the pins. I challenged that and you doubled down, though it seems that you later accepted that there might be. If pointing out you error is an attack, then this forums is pointless. You're apparent lack of understanding of pin stress (based solely on what you've posted), and continued refusal to acknowledge how it factors into what happened, is the main, and possibly only point of contention.

The details are moot for most folks because the message should be that acid baths weaken plates, which should be fair warning without examining the specific mode of failure. However if there's interest is comparing our different theories vis a vis pin stress as opposed to stress risers (absent pin stress) was the proximate cause, I'll be happy to continue. For those who want to think about this of even do some experiments, they might take an old chain, cut it into sections, with some links pinned, and some outer plates with the pins pushed out.

Camilo

All this stuff can be interesting, but the real message is: clean and lube your chain and it will last longer.

cyccommute 

This statement is not about the message: “I'm starting to believe that you can't read, either. ----- Where did I say that hydrogen embrittlement happens in air? This is simply more of your strawman tactics to cover your own lack of expertise.” It’s not the only time in the thread where you have made similar statements. On the chemistry, I am on very solid ground.

And you insisted that the chemical bath had nothing to do with the chain cracking. I never said there was no plate stress at the pins. I specifically pointed out that the stamping on the plates raises stress risers that facilitate the cracking. Placing the chain in the chemical bath did indeed cause the cracking. The evidence is clear from the cracking noise that happened upon the chain being put into the acid bath. I have even agreed that chains can crack from the plate stress but it is a rare occurrence absent some kind of chemical exposure that leads to cracking. Salt or acid doesn’t matter, although a salt solution is slower.

Additionally, I pointed out that the volume of rust formed is many times the volume of the iron oxidized. A very small amount of iron can produce a large amount of rust. Thus rusting really isn’t’ the reason for the chain cracking either. The amount of iron removed is insignificant.

Go read posts 4 and 5 and, for good measure, elfmachine’s post 7. I already said that acid baths shouldn’t be used on chains. How about you do the experiments? What are you waiting for?

base2 

JFC
Is any of this bickering from anyone adding value? In case nobody noticed: Where's the OP? From the actions of all involved, I'd be surprised if he ever logs back to BF ever again.

Did no one notice the conspicuous absence of a picture corroborating the OP's testimonial? Way to go. Well played. Hook, line, & sinker.

Camilo

He probably got the simple message stated very early, when he was still interested and paying attention: not lubing chain is bad. Lubing it is good. He probably didn't care about the arcanum or who was winning an irrelevant argument.

Duragrouch

Hmm... this talking about stresses due to the press-fit pin in the sideplate, in a corrosive bath, makes me wonder if any stress-corrosion cracking (an actual technical term), was going on? Just an esoteric point. Lube, don't let get rusty, clean periodically, replace when stretched beyond spec.

FBinNY 

Yes, IMO this EXACTLY what is going on. However, there's strong disagreement on the specific mechanism.

But it most definitely is what caused the OP's chain outer plates (only?) to crack. If you search under "bicycle chain plates cracking" for images, you'll see how common this is.

FWIW cleaning isn't the only cause. Sometime back a major chain maker experienced large numbers of plate failures, not due to corrosion, but rather to tolerance and QC issues.

Duragrouch

It doesn't take much. It's been many decades, but if I recall from my machinist days, a "half-thou" (0.0005") per inch of diameter was a heavy press fit (steel in steel). At much smaller diameters like a 1/4", I think it was a "tenth" (0.0001") or even "half a tenth" (0.00005"). Again, assuming my memory is at all correct, when you get down to the diameter of bike chain pins and plate holes, the tolerances get awful tight. It's really amazing for something so inexpensive. For some things, like ball bearings, if I recall, at least back in the day, perfect manufacturing precision was not possible, and they had high-volume ways to sort parts to get desired qualities; most important on ball bearings was that all the balls in a given assembly were exactly equal in size, more important than a slight difference in that size from assembly to assembly.

choddo

To be fair, some of us, me included, expressing horror and disbelief that he didn’t bother looking after it properly in the first place and was looking for a miracle space material that would let him get away with that was probably ruder and more offputting than the bickering.

smd4

You're probably right. Seeing chains as described by the OP was par for the course working in a shop that catered to families. However, this forum seemed to be more of an enthusiast's hangout, where people generally took care of their bikes, worked on them themselves, knew about basic things like chain maintenance, etc. So when I see situations described by the OP, I'm sometimes taken a little aback.

cyccommute 

I have never said anything otherwise. I have even said that the fracture followed stress lines exacerbated by the stamping of labels on the metal in high stress areas.

Yes, indeed there is disagreement about the mechanism. I hate to rehash this but you said, specifically, that the acid bath did not cause the chain to crack. elfmachine stated that he rode the chain until it loosened up. It is likely that no cracks were there. If elfmachine had simply kept riding the chain, no cracks would likely have appeared. If elfmachine had used so other non-acidit form of rust removal like a chelating agent, no cracks would have happened. The chain could have been used for hundreds to thousands of miles with no cracks.

Placing the chain in a highly acidic solution gave the mechanism for accelerating the cracking along the lines of stress. Almost as if the acid bath caused the cracking.

Since it is unlikely that you will perform the experiment, I guess I’ll have to do it. It’s going to take a while to either find a severely rusted chain or make one in my area. Winter isn’t exactly wet here.

FBinNY 

Please scroll back through and tell me where I said anything of the sort.

rekmeyata

Hydrogen embrittlement would take at least a couple of years for that to cause enough of a problem to break a chain. What probably broke the chain was the amount rust was too bad, combined with riding it under the stress of being stiff caused the chain to fail.

Never use Simple Green or any household cleanser that contains citric acid.

If you have a badly rusted chain like the poster of the original question it would be a lot wiser to replace the chain instead of trying to clean up the rust and keep using it.

If you have no choice then remove the chain and soak it overnight in WD40, then scrub it with a steel wired brush, rinse under very hot water, if afterwards the links are still stiff you maybe out of luck, you can try to put it back into the WD40 overnight and repeat the above process, if the links still come out stiff the chain is definitely bad. Then once that is cleaned up, then use a regular chain degreaser, to take the WD40 off, then either blow the water out of the chain with compressed air, or let it dry overnight, then use your usual chain lube. To be safe however, just replace the chain and forget about doing all that work.

Andrew R Stewart 

Perhaps it's time to close this thread down? Andy

Duragrouch

I tried Simple Green in water for a daylong soak, didn't do a good job of cleaning, and thankfully, no chain cracks. I don't know the ph of the stuff.

Citric acid... uh, aren't "citrus" cleaners used everywhere as a more environmental degreaser? I'd love to have an ultrasonic cleaner with dilute citrus cleaner, but no?

Of late, I've been cleaning the chain with an on-bike cleaner, using tiki-torch fuel, which is 99% mineral oil with a bit of lemongrass and/or citronella oil for anti-bug I think; Mostly-full bottles of the stuff are cheap at goodwill at the end of summer.

rekmeyata

Why? did I, or someone else say something that was offensive in nature?

Andrew R Stewart 

Not you and not yet offensive words... Andy

Duragrouch

It's a spirited debate, and I also don't like any rudeness. But, I have learned things, despite my engineering knowledge, sometimes remembering things from college metallurgy that have fallen through the cracks in the mental floorboards, as it were.

For one thing, don't use Simple Green (I tried once, worked poorly, and thankfully no damage to chain), but more importantly, someone advised against citric acid, which I think may be present in citrus cleaners, and I thought that was a widely used, more environmental alternative to petroleum-based solvents? Haven't heard a reply on that question, but I hope to. A quick search brings up Finish Line Citrus Bike Degreaser, been around since 1988, my guess is does not damage the chain. Wiki says citric acid can remove rust, and act as a chelating (cleaning?) agent. It's been 40 years since I balanced a chemical equation, so I've not a clue regarding interaction with steel or aluminum.