1675 corrosion question

[Elliot1957]

Does some corrosion on the inside of the case back on a circa 1968 1675 GMT greatly affect the value, and will the corrosion continue to get worse? can anything be done to stop or fix it ? Would you let it stop you from buying an otherwise beautiful watch??

[secondhandcrowns]

That my friend is not that bad at all.

[drainaps]

I would not worry too much. Watch is overall in good shape. I don't think that can substantially affect value. Those in this hobby know about pitting and corrosion in earlier Rolexes. Your case back is not that bad.

If you want peace of mind, you could try a laser welding restoration of the case back. Search the forum for examples and practitioners. I would not do it though.

[crowncollection]

Not to bad IMHO it can be fixed if it bothers you.


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[Puffy]

i think a bit of corrosion on the very old ones add a bit of character

as long as it's not on the hands and totally visible i'd have no concerns

you're not going to use it for diving etc so i'd say it's good to go

it'll make a good daily wearer. slap a fat font insert on it and you have a winner

i like the matching hands and dial. nice patina

[Vincent65]

As far as I know, corrosion is unstoppable once it sets in, although you can obviously limit its advance with careful use and keeping it clean. It's my thinking that this sets in due to sweat ingress under the lip of the case-back over many years. I've seen worse, but I've seen better too. Personally, that would put me off, because I like a clean case, and corrosion undermines its 'Oyster' credentials, even if you're not planning on diving with it. I actually don't mind a little corrosion on the hands, but the case has to be intact. Each to their own, though. I like the dial and hands, and the insert looks good. Needs a new bracelet though, or restore that one. Depends on the price, and what you're looking for.

[taxico]

the midcase would usually have corresponding corrosion seen on the caseback... if that case back in your original post is original to the watch, it's mostly located on the outer area of the gasket, so all is well.

i usually prefer a case without corrosion, but if the price is right, i'd go for it.

[swish77]

If the case corrosion is so bad that the watch doesn't pass a pressure test for water resistance/proof, then I'd be concerned. Otherwise, it's invisible when on the wrist and would be a non-issue for me. Wear and tear is what can be charming on these old timepieces (to a certain extent.) Very nice GMT!

[Elliot1957]

Thanks everybody. The corrosion, in its location, does not bother me, so I'll keep it.

[Tools]

Corrosion can be arrested chemically.. Bob Ridley at Watchmakers.com knows the process and can even press in a new mid-case seat if inner corrosion is too bad, saving an original case and serial..

Give him a call and chat with him about your case and caseback to see if it's worth having done..

For the right watch, no problem - I would definitely take the leap and do the repairs..

[Vincent65]

Originally Posted by Elliot1957

Thanks everybody. The corrosion, in its location, does not bother me, so I'll keep it.

oh, so you already own it - I thought from your OP that you were considering it, as you didn't say it was yours...

[timelord]

Originally Posted by Tools

Corrosion can be arrested chemically.. Bob Ridley at Watchmakers.com knows the process and can even press in a new mid-case seat if inner corrosion is too bad, saving an original case and serial..

Give him a call and chat with him about your case and caseback to see if it's worth having done..

For the right watch, no problem - I would definitely take the leap and do the repairs..

Welding a new seat?

I would be more concerned about the mid case if the case back has this pitting as they usually go hand in hand. Pitting is like rust on your car or any metal with in the presence of the right oxidants. Once it starts you have a chain reaction and the only real cure is to grind them out, but with a watch it is not an option in that section of the case.

What most people fail to realise is that these stainless metals are not heat treatable, but they do have a high coefficient of thermal expansion. Therefore, welding will expand the metal significantly. The weld will, at least partially, begin to solidify in that expanded geometry. When it completely cools down, it may actually return to near cold dimensions. However, the weld zone will be stressed internally because of the shrinkage. If you still want to dive with the watch, it is recommended to anneal it before machining and perhaps repeating the procedure afterwards. This will remove any welding-induced and cold-working stresses. The annealing process will have to be done slowly and carefully to avoid permanent distortion and ruin the proper fitup of parts on reassembly. I would not expect this to be a cheap fix.
If you can live with rust on your car, then I would look at it as living with rust on a watch.

[Michael M.]

Watch looks pretty good and the case is nice. Just FYI......the dial is a service replacement. Probably replaced at the NYC RSC in 1984 judging from the case back markings.

[skprd13]

Rust never sleeps!

[Tools]

Originally Posted by timelord

Welding a new seat?

I would be more concerned about the mid case if the case back has this pitting as they usually go hand in hand. Pitting is like rust on your car or any metal with in the presence of the right oxidants. Once it starts you have a chain reaction and the only real cure is to grind them out, but with a watch it is not an option in that section of the case.

. . . .

No, I'm not talking about welding at all.... A good watchmaker can turn a new seat and press it in place to restore an original

Here is an example of one of Bob Ridleys Projects..

https://www.rolexforums.com/showthread.php?t=91914

[timelord]

Originally Posted by Tools

No, I'm not talking about welding at all.... A good watchmaker can turn a new seat and press it in place to restore an original

Here is an example of one of Bob Ridleys Projects..

https://www.rolexforums.com/showthread.php?t=91914

one would want to make sure that where the seat is pressed in place moisture cannot creep under this new seat where the surfaces touch each other, otherwise one would have crevice corrosion between the new seat and the case.