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I shall be getting a nice titanium seat post for Christmas (if Yodel get it here) and I'll be fitting it to my steel Singular Swift. The post is 420mm long, so there'll be a fair bit in the frame.
I've always used a smear of coper grease on my Thomson in the same frame to protect against galling & corrosion and it's been fine for years of riding in all weathers (although I do tend to be a tad anal when I've been out in the rain and always remove the post to allow airing, which in itself will stop galling).
I've always used copper grease on static, metal-on-metal parts, but have a vague recollection that I read somewhere that copper grease may actually promote galling with certain metal combination.
Would copper grease still be thing to use with titanium & steel, or is there something better?
Copper promotes galvanic corrosion so shouldn't be anywhere near dissimilar metals, especially seat posts! Not sure why it would cause galling though, unless you're moving it in and out constantly that shouldn't be a worry.
I bought this when I got my Ti Frame:
If it isn't coppaslip repackaged it sure looks like it. Never had an issue with alloy bb cups or thomson posts in a Ti frame using it (so ymmv with a steel frame!).
Do many people buy Ti posts anymore? generally more expensive and heavier than Carbon innit?
Anyway 'Galling' tends to affect Stainless on Stainless assemblies, especially threads, it's essentially Frictional cold welding.
I used to work with a chap who wrote a lovely detailed paper on it for a job we were both on, the long and short of it was a recommendation to use a Graphite loaded lubricant on fixings (DAG 580 IIRC).
But you're describing contact between two dissimilar metals so does a Ti post clamped into a Steel frame cause more of a corrosion issue than an Aluminium post would?
Absolute 'best' solution is just to use an undersized post and a Plastic Shim. 🙂
I think that galling is associated with movement under pressure and shouldn't really affect a seat post/frame. A Ti seat post bolt might well cause a problem though
You can get specific titanium alloy anti-seize pastes and non-metallic anti-seize that will do everything, which is what I'd look at
Moly paste is the answer.
I've always used Coppaslip/Ti Prep and had no problems.
Moly paste is the answer.
That's for moving parts during assembly, like when assembling an engine?
Unless you're confusing it with a product form the liquid-moly brand?
Copper promotes galvanic corrosion so shouldn’t be anywhere near dissimilar metals, especially seat posts!
Not 100% sure on that, to get galvanic corrosion you need a circuit and an electrolyte. The typical examples are a ships zinc anode, which is bonded to the hull and the engine and anything else via an earth strap/wire, and the salt water. The zink then fizzes away protecting anything it's connected to, or aluminum boats which have been known to sink in harbors when an earth leakage via their shore power cables turns them into a big galvanic cell with the steelwork of the harbour!
If all you have is 2 metals, and copper sticking them together you're no worse off than if they were just stuck together anyway. The grease component is keeping the 'electrolyte' out and the copper is just there as a last resort keeping the metals a few microns apart if the grease washes away.
The modern equivalent is ceramic particles in a silicone based grease which is both more waterproof and more electrically insulating. Not that it really matters, it's actually good practice to put some non-conductive grease on electrical connectors in order to actually promote better contact!
I've had an aluminum brake mount thread corrode away around a steel bolt because salt got at it as the thread was open at the other side of the frame, but I'm not sure a thin smear of grease would have helped there, it was just a poor design that collected road grime in the wrong place.
Mmm. What post as thinking of treating my steely to one
https://singularcycles.com/products/singular-ti-seatpost
Still a silly amount of cash for a seat post (it is Christmas) but considerably better value than a ti. Thomson (£350!
Anyway ‘Galling’ tends to affect Stainless on Stainless assemblies, especially threads, it’s essentially Frictional cold welding.
This was my understanding of galling - is this correct then?
I once used margarine as a seat post lube when I was desperate. It worked perfectly for years on a steel frame with aluminium post.
Some people even eat the stuff
If it is not recognised by the human digestive system then sure wouldn't be going on my bike
;d
According to the video posted in this thread yesterday you should be using a nickel based anti-seize
https://singletrackmag.com/forum/topic/anti-seize-ally-to-ti-ally-to-carbon-and-carbon-to-carbon/
According to the video posted in this thread yesterday you should be using a nickel based anti-seize
I must confess to being a tad more confused now, than before I'd posted.
Since Copper grease seems to be synonymous with 'anti-seize' I've always used it on static, metal-to-metal parts (without, I have to say, any issues). If it actually promotes galvanic corrosion between dissimilar metals, I may have a problem with my aluminium HTII cups torqued well up on my steel gravel bike!
I asked primarily as titanium is a rare treat for me and I'm unfamiliar with it. I suspect that that my propensity to remove the seat post after wet rides, will be enough to prevent corrosion/galling and I don't imagine that a smear of copper grease will be catastrophic.
Yeah it rocked my boat as well. Makes sense though.
I've a Ti frame with an alloy post in smeared in copper slip. It's been fine but I do have an alarm set for twice a year to move all my posts and reapply copper slip if needed. Seen a lot of stuck posts on customers bikes so maybe it's overkill but better safe than sorry.
I think folk only have problems when they put nothing on and leave for years.
My interpretation of that video was that copper may not be the best but it’s mostly pretty good and I will continue to use it. If I didn’t already have a tub of Copperslip that is going to outlast me I’d buy the Nickel stuff though just because why not
+1
My interpretation of that video was that copper may not be the best but it’s mostly pretty good and I will continue to use it. If I didn’t already have a tub of Copperslip that is going to outlast me I’d buy the Nickel stuff though just because why not
This +1. For a bike that's easy to inspect I'll carry on with my 500g tub of copper grease
...or is there something better?
Yes, but I won't be buying it
It's a nice post, very long & nicely made (better pictures on the Singular site) and has gone onto my Mk IV Swift.
Whether it's actually a worth while purchase is hard to say - I'm not convinced (yet?) that it's going to be more comfortable than the aluminium Thomson it replaces, but I'm unlikely to ever be able to afford a titanium frame, so as a treat it's a very nice thing indeed & compliments the second hand ti. flat bars I bought off here.
Back to the galling/galvanic corrosion issue, and having watched the above video which talks of galvanic corrosion being an issue between different metals with moisture at the interface, I noticed, when riding home on Christmas Eve, that my aluminium stem & titanium bars were dripping with condensation & moisture from thick fog. It dawned on me that the bars where clamped into the stem, dry, around 5 years ago and hadn't been touched since. The bike's been out in all weathers and I expected the bars to be welded solidly to the stem, but no, they were absolutely fine. Perhaps it's not quite as big of a problem as I'm thinking.
Galvanic corrosion affects two dissimilar metals in the presence of an electrolyte. In this case Ti and the sort of alloys found in bike frames are miles apart on the galvanic series so are definitely at risk. In this case the copper grease acts as a conductor (because copper is sufficiently conductive) and accelerates this process.
Anyway ‘Galling’ tends to affect Stainless on Stainless assemblies, especially threads, it’s essentially Frictional cold welding.
No, it's found on sliding surfaces where one picks up the material of the other (like delamination).
I have never had galvanic corrosion using coppaslip on dissimilar metals - indeed the opposite Never a sized bolt. I slather my bikes in it - stainless bolts into alloy, Stainless bolts into TI, alloy bolts into steel even hi tensile steel into alloy etc etc
I know you know your stuff on this squirrelking but is this one of those theoretical issues that rarely manifests in practice?
Nice post you have there
@tjagain dunno to be honest, it could be one of those things that's temperature dependent as well but when it comes to posts in frames I'd rather not take the risk adding to the likelihood of it seizing.
Galvanic corrosion affects two dissimilar metals in the presence of an electrolyte. In this case Ti and the sort of alloys found in bike frames are miles apart on the galvanic series so are definitely at risk. In this case the copper grease acts as a conductor (because copper is sufficiently conductive) and accelerates this process.
A conductor of what?
Source for this assertion?
No, it’s found on sliding surfaces where one picks up the material of the other (like delamination).
Absolutely, it can affect several metals including titanium and aluminium in the context of bicycles. This will include threads as surfaces sliding under pressure
Galvanic corrosion affects two dissimilar metals in the presence of an electrolyte. In this case Ti and the sort of alloys found in bike frames are miles apart on the galvanic series so are definitely at risk. In this case the copper grease acts as a conductor (because copper is sufficiently conductive) and accelerates this process.
A conductor of what?
Source for this assertion?
I think that you might have this confused, which is why I asked those questions^^
Galvanic corrosion is a movement of ions through an electrolyte, rather than the solid copper, which is what TINAS was saying^^
There's a zinc-based product, catchily named Bicon X1, that increases electrical contact while preventing galvanic corrosion. Galvanic corrosion isn't about being a conductor in that sense
The electrolyte for bicycles in the UK is typically water with a soluble salt, e.g. sweat, road grit, etc. Keep the electrolyte out of the metallic mix with grease, or similar, and you won't get galvanic corrosion.
The suspended copper particles mean that the grease isn't completely forced out of a joint. It's true to say that there are better metallic and non-metallic particles than copper for certain applications, but copper is tried and tested by many cyclists and works for us
Slight diversion, Alex Steele is doing a fascinating project trying to forge a titanium knife with a steel core. Turns out that to get titanium to really bond to steel you need really clean surfaces, an argon jacket and a massive steam hammer!