Rusty chain restoration

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My Grandad (who spent his entire life farming) used to soak all his rusty chains-both industrial and bicycle- in WD-40. This left the surface clean and the chain flexible but tended to evaporate the internal lubricants, so his next step involved a three-day soak in a 50/50 mix of kerosene and motor oil. The finished, towel-dried chain didn't retain the original finish though-the light corrosion mixed with the solvents and lubricants to form what Grandad called a 'plum coat'-a hard, slick light-brown coating that protected the surface from further rust for years to come...not sure if you would want that look on your chain but it was very durable.

That sounds like something my Uncle would do too. I spent my summers on his farm in high school.
 
All of mine had a master link... You might need to do an initial scrub with a wire brush to find it. Don't forget to degrease before using the Evapo-Rust, as it really speeds it up if it doesn't have to work through a layer of oil.

Come to think of it I may have had a chain or two where the master link was one of the kind where I needed to flex the chain sideways for the side plate to come off....It still was a different looking llink than the rest, once it was cleaned up some.

The rest had that spring clip holding the plate to the link.
I suppose it is possible someone used a chain tool to just install a regular link as well....but in my experience fairly unlikely. As far as using a regular chain tool you do have to modify some of them by grinding off some of the inside protrusions. I don't own any that aren't already busticated so I use caveman means usually.
 
I know this is an old thread but I felt i had to address the idea of using Evaporust on chains. I rebuild bikes for a hobby, like most here, I sell sell or donate the ones I don't keep. On a few occasions, I used Evaporust on chains. What I got was a beautiful chain, like new. The first one, I put on the bike and rode 3 blocks to the supermarket, the chain snapped before I got there. A link had broken in half. Ok, maybe the chain was weak. Next one went on a bike I sold, next day the buyer came back with a broken link in the chain. i had one more which i put on my bike to test, sure enough, the chain broke. 100% failure record, This stuff somehow weakens the type of metal used in chains. I love it for so many other things, and if bikes were for display only, it makes a rusty chain look so nice. Anyway, hope I helped someone avoid a chain failure
 
I know this is an old thread but I felt i had to address the idea of using Evaporust on chains. I rebuild bikes for a hobby, like most here, I sell sell or donate the ones I don't keep. On a few occasions, I used Evaporust on chains. What I got was a beautiful chain, like new. The first one, I put on the bike and rode 3 blocks to the supermarket, the chain snapped before I got there. A link had broken in half. Ok, maybe the chain was weak. Next one went on a bike I sold, next day the buyer came back with a broken link in the chain. i had one more which i put on my bike to test, sure enough, the chain broke. 100% failure record, This stuff somehow weakens the type of metal used in chains. I love it for so many other things, and if bikes were for display only, it makes a rusty chain look so nice. Anyway, hope I helped someone avoid a chain failure
Due to the way the chelation process works, selectively making it more attractive for iron oxide to enter solution, but having no effect on base metal, I'm skeptical of the claim that Evaporust weakened the chains. Chains that were rusted badly enough to require de-rusting may well have had damage before being de-rusted.

One experiment to prove your claim would first pull test rusty chain segments BEFORE de-rusting, then expose to Evaporust, then pull test again with resultant fracture at the same, or lower levels of stress.

There is one case where Evaporust apparently could cause weakening of base metal. If a surface is not entirely submerged, the line where liquid surface and air meet, can be damaged. The base metal may be rusted, and etched in a continuous cycle at this interface, causing a score line or notch to be etched into the metal. Notches or even scratches in metal surfaces have the effect of multiplying stress in the surface. These sources talk about this effect in more detail:
https://aplanelife.us/blogs/f/evapo-rust-–-miracle-or-maladyhttps://www.practicalmachinist.com/forum/threads/evaporust-side-effects.246805/
Personally, I use phosphoric acid for the majority of my de-rusting chores, including on chains because:
- Unlike most available acids, phosphoric does not appreciably attack base metal, only rust.
- Unlike most available acids, phosphoric converts iron oxide to iron phosphate, which is resistant to re-rusting. This is a huge advantage, in my opinion, an advantage that phosphoric acid has even over chelating de-rusting solutions like Evaporust, which leave the surface vulnerable.
 
Personally, I use phosphoric acid for the majority of my de-rusting chores, including on chains because:
- Unlike most available acids, phosphoric does not appreciably attack base metal, only rust.

Reminds of my days as a bike mechanic. We had a contract to service all the Airdynes in a local health club and one day I was called over to fix every one of them.

It seems a maintanence guy there decided muriatic acid (IIRC) would be a really fast way to clean all of the chains. I got to replace every chain on every piece of equipment he worked on...

I don't bother with rusty chains unless they are something special. Especially on motorcycles, if they are suspect for any reason they get trashed.
 
Never, never, never use any acid on a skip tooth chain or antique lucky 7 seat post. The steel is extremely porous and you will end out with a bunch of dissolved apart chain pieces or a seat post with splinters. Use a solvent, like acetone, in a jar, and shake it for 5 minutes. Take it out and pour boiling water over it. Then put the chain back in the jar, covered with Simple Green. Shake it for 5 minutes. Then scrub it with a small brass brush. Then pour boiling water over it. If it’s still rusty use a non corrosive commercial rust buster, watching it carefully until the rust is just gone. Then use penetrating oil, working each link, back and forth, on a rag, to further clean and free up any tight links. Wipe it down well and put on chain lube. They can end out looking like new. I use a lot of vinegar, oxalic acid and phosphoric acid to bust rust, and they are cost effective and work well, but never on a skip tooth chain. A modern chain can take acid cleaning. I know a lot of RRBers have posted about ruined skip tooth chains from vinegar soaking. This skip tooth block chain from the 1890s was cleaned this way.
9835C389-48AE-4435-9865-C56973CDEDAD.jpeg
 
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Reminds of my days as a bike mechanic. We had a contract to service all the Airdynes in a local health club and one day I was called over to fix every one of them.

It seems a maintanence guy there decided muriatic acid (IIRC) would be a really fast way to clean all of the chains. I got to replace every chain on every piece of equipment he worked on...

I don't bother with rusty chains unless they are something special. Especially on motorcycles, if they are suspect for any reason they get trashed.
The only rusty chain I ever attempted to reuse is the only one I have ever had break. It was a modern KMC chain, wasn’t overly rusty and it was cleaned with chain cleaner. Luckily I was only taking it easy.

I now bin any suspect chain too.
 

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