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Titanium-Stainless Steel Galvanic corrosion 3

D

doobes

Marine/Ocean
Joined
Jun 13, 2025
Messages
8
Hey all,

First time post.

I'm a retired electro-mechanical engineer. Spent my career designing, building and operating Remotely Operated Vehicles.

The challenges are different nowadays.

Today's challenge is a Seiko Kinetic Titanium watch I bought off the 'bay..

Thusfar, I've done fairly well buying semi-derelict Seiko Kinetic Titanium watches and rehabilitating them.

Until this one:

image.png.66f821cd5ece234a64946a70326e19b4.png

The loose second hand should have been a tip off, but I was smitten with the looks and paid more for it than I should have.

It shows up, and it's a friggen mess. All the stainless steel parts are severely corroded, to the point that they are pretty much welded to the titanium via galvanic corrosion that they are in contact with.

I've soaked it in spirits for a couple of weeks, to no avail.

Any thoughts about something to soak it in that would loosen the attachment but not affect the Titanium?

Thanks in advance

chris
 
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You are looking to dissolve oxides of iron, phosphoric acid is available at your hardware store and typically is sufficient for the job. Pickling solutions for stainless steel are commercially available and do remove rust. They typically have nitric and hydrofluoric acid, check for compatibility with titanium. Heated citric acid is also useful for cleaning stainless steel and also commercially available.
 
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phosphoric, citric or straight nitric acids will not attack the SS but should attack some of the products of corrosion.
After all you just need enough attack to allow you to get it apart.
Then you can really clean things.
 
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Thank y'all.

I'll get some citric acid and try that.
 
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You might be able to pick some up in the home canning department of your local hardware or farm supply store.
I would start with 10% citric at 120F.
Give it 15-20 min and see if it is loosening up.
You may need to go longer, you may also need to go hotter (up to 150F).
 
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I can get it at the local Walmart.

Thanks for the solution numbers.

chris
 
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Well,

The big nada with citric acid.

Onto WD-40, and then PB Blaster.

cheers
 
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So,

In a last ditch effort, I'm trying an Alum solution in heated water.

Removing broken screws with Alum bath

It took some thinking on how to keep this at an elevated temperature.

So, I got out my Anova Sous vide machine, and put it in a pot with sufficient water to allow continuous operation.

I put a biscuit cutter ring in the pot and then a small jar on the ring. I filled the jar up to the level of water in the pot and then let everything come up to temperature.

I added alum, spoonful, by spoonful until it would no longer dissolve.

The watch case, which has a string stretched, was lowered in the jar.

And now we wait...
 
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Well,

Nothing whatsoever with the alum solution.

This is what I'm trying to get out:

stuck-pin.jpg

Any suggestions would be appreciated.

thanks

chris
 
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Driving corroded pins is risky business. If you strike the pin you risk turning it in to a rivet. Generally, you punch needs to be smaller than the pin diameter to avoiding this but there impossible with such a small pin.

There is a significant difference in coefficient of thermal expansion between titanium and stainless steel. You can use this to your advantage. The pin is stainless and the watch body is titanium correct? In this case you're going to have to cool it to reduce the interference fit. Dry ice is is readily available. Can you get your hands on liquid nitrogen? Get it cold and push the pins out.
 
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TugboatEng said:
Get it cold and push the pins out.
Click to expand...
Unfortunately it's a blind hole, so there is no push.

3DDave beat me to the suggestion of EDM.

Or maybe it's time to give up on this case and salvage the movement, bezel etc. for another project.
 
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Well,

Neither EDM nor liquid nitrogen is realistically available.

I've not given up....

Yet

;)
 
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Dry ice is available and the difference in CoTE between the two materials is substantial. If you can get it cold enough you might be able to use tweezers to extract the pin.
 
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There are plenty of EDM shops in the world. I suspect that is how the holes were originally made, but now I want to know for certain.
 
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3DDave said:
There are plenty of EDM shops in the world. I suspect that is how the holes were originally made, but now I want to know for certain.
Click to expand...
You are prolly right.

The crux of the issue is this is a $70 watch. How many $hundreds would it cost for an EDM shop to drill this out?

Cheers
 
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The money in a shop is tied to getting material, complexity, and reducing time. In this case you are supplying the majority of the material, the complexity is very low, and if you mention that any time in the next 6 months is OK, it may turn out to be inexpensive. If the point of this is the recovery of the watch and not the value, it's up to you to decide if their price is good. For them it's sinking a pin hole a small depth, 4 times. Bring donuts with the watch; that may reduce the price further.
 
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