Difference between 18k and ss ?

[roosvelt]

If you have 2 Oysters rated for 100m, one is make out of 18k and the other ss. Wouldn't the 18k case back be thicker than the ss to make up for it being a softer material ? Anyone have answers or better pic to show the difference? Exaple would be 36 DD and a 36 DJ !

[Bigblu10]

No. 18K is not as soft as you think, and it is able to achieve the same waterproofness rating as stainless steel. Steel Subs are exactly like 18K solid gold Subs. Same 1000ft. rating, regardless of metal. Case back, case, crown, bracelet all the same. Only difference is solid gold cases have a bit more material milled out of the inside where movement sits.

[TonyD]

I'm an engineer by day but can only guess. My feeling is that at 100m the seals are doing most of the work.

Obviously the really deep divers like the DSSD require a lot more material.

[shofzr]

Originally Posted by roosvelt

If you have 2 Oysters rated for 100m, one is make out of 18k and the other ss. Wouldn't the 18k case back be thicker than the ss to make up for it being a softer material ? Anyone have answers or better pic to show the difference? Exaple would be 36 DD and a 36 DJ !

Sent from my iPhone using Tapatalk

[roosvelt]

Thank you all for the info especially Adrian for the pictures.

[037]

Originally Posted by TonyD

I'm an engineer by day but can only guess. My feeling is that at 100m the seals are doing most of the work.

Correct. 100m is roughly equivalent to 10 ATM or 150 PSI. At that pressure you won't see enough deformation of the case back for the metal itself to be the point of failure. The seals are doing the work.

Another example is the 18K yellow gold Sub Date. It's rated to 300m/1000ft and retains the same case and case back dimensions as its stainless counterpart. That's good for over 30 ATM / 450 PSI (since they have safety margins) without case or back deformation.

The beauty of the system is that as pressure increases, the seals get stronger up until the point of failure -- which is by my best guess at least 25% higher than the respective water resistance rating.

HTH

[Chute]

I wonder if this is why there is no precious metal DSSD.

Maybe someone did the math and the PM’s couldn’t handle the pressure?

[037]

Originally Posted by Chute

I wonder if this is why there is no precious metal DSSD.

Maybe someone did the math and the PM’s couldn’t handle the pressure?

The titanium case back is what helps the DSSD. Even the HEV should function in an 18K case without ingress. If I had to guess, Sea-Dweller sales aren't high enough to justify a model in gold, be it 4000 or Deep Sea.

But, I've not done any math. I'm just guessing based on market demand.

[Hunter87]

The upside of SS is it’s corrosion resistance the down side is it’s a little soft hence the many dented Rolex case pictures you can google online

[037]

Originally Posted by Hunter87

The upside of SS is it’s corrosion resistance the down side is it’s a little soft hence the many dented Rolex case pictures you can google online

Every metal watch can be dented. This isn't exclusive to any one brand.

The discussion in this thread is 18K gold alloy versus stainless specifically in terms of water resistance.