platinum alloy choice help

[justpeachy]

Hoping to get some insight re: platinum alloy choices. I've searched and read through most relevant threads here, and done my fair share of googling. I thought it might be helpful to ask specifically regarding what I like/hope for, and the design of my ring (as I understand sometimes pave vs. polished shanks, mixed metals, etc. can affect what someone may choose).

I'm going to have an EC bezel set in rose gold, with a platinum halo surrounding. The shoulders will also be pave in platinum, tapering down to a hand carved floral platinum accent with a diamond center. The shank will transition to rose gold from then on. I'm attaching one of my inspiration photos (by CVB) to better demonstrate how it will flow.



The options I've been presented are PT90 with iridium, or PT95 with rhodium (I'm researching under the assumption that they meant ruthenium as I can't find information on a rhodium mix. If there is one please correct me!)

I hardly ever take my rings off. I'm not necessarily hard on them, but they do get a ton of wear. I would like the platinum to stay as bright white as possible. I do not want it to be brittle. I'm happy to send it off for a polish annually.

And bonus question: Will the patina develop just as strongly around the halo and pave shoulders as it might a shank? Is it possible to polish in those areas or will that affect the milgrain? Thanks in advance for any info!

 

[yssie]

PT 900/Ir (iridium) or PT 950/Ru (ruthenium, you are correct, no rhodium in this discussion) are both excellent choices. The alloy you want to avoid is PT 950/Ir.

No alloy of platinum will change colour. The reason WG “turns yellow” is that WG is (usually) actually a light yellow, but is rhodium plated to look bright chrome white - the rhodium layer is ~1micron thick. This plating slowly wears off with time and use, revealing the light yellow metal underneath. Platinum is not plated.

A cast piece will be less brittle than a die-struck or hand-forged piece. In practice - don’t worry about it. Truly.

Patina is the visible result of regular abrasion - will develop wherever the piece encounters wear. Virtually any part of a piece can be repolished and milgrain can be reapplied - this is not a significant or risky repair. Again, not something to worry too much about

 

[TreeScientist]

As @yssie said, both PT 900/Ir and PT 950/Ru are excellent choices. PT 950/Ru has a slightly higher susceptibility to cracking during the casting/forging process, so some designers doing more complicated work prefer to work with PT 900/Ir, but they are practically the same in everyday wear in regards to durability and resistance to scratching (cracking in either alloy only occurs when the alloy is heated and/or placed under high pressures such as during casting or forging)

I would go with whichever alloy your designer/setter feels most comfortable working with for this particular ring design. Each jeweler has their preference, and some will choose one allow over the other depending on the application.

 

[chappy]

Hi, I just happen to have plat rings in both alloys you're considering, and if you've already read all the essays then perhaps more photo comparisons will help.

The PT900/Ir is by Mark Morrell, and the PT950/Ru is from Tiffany's. Both rings are about the same age (7 years), but as the Tiffany's came to me second hand I'm not sure if it's been polished before (definitely looks shinier). They're both very nice colors in person, the difference is absolutely minor and I don't think you could go wrong with either! Although, PT950 is a touch warmer, which I personally think might match better with the rose gold.

 

[yssie]

Similar ring styles, similar age, similar wear habits, same informed owner - who says this alloy distinction is nothing for the end consumer to fret over. Doesn’t get more reassuring than that thanks @chappy!

 

[chappy]

Oh heck, my wedding band is RG so I might as well give you a sandwich so you can compare yourself!

Personally I find PT950/RG more matchy and PT900/RG more contrasty.

 

[motownmama]

I had to have my plat 3-stone remade using 950/RU. The previous alloy was like playdoh on me! I pair it with some Tiffany bands, so in fact they look harmonious and wear similarly. I concur with the above posters on the 2 best choices for plat alloy. Good luck

 

[latte_espresso]

I was told that most designers (Tiffany/Cartier/HW) uses 950/RU. So I went with the 950/RU.

 

[sledge]

Metal types came up during my custom build w/ DK. The first couple of pages has some good information and pictures that may be helpful. The metal discussion then fades until around page 6 or so when I am forced to make a final decision. In my case I ended up going with the DK's recommendation to use their custom WG/palladium alloy mix.

Not sure whom is making your ring, but it might be a worthwhile conversation. By the way, very pretty design.

Link to the thread:
https://www.pricescope.com/community/threads/dk-bgd-custom-setting-the-home-stretch.240843/

 

[diamondseeker2006]

Either of those two alloys is totally fine. I have both and can't tell a bit of difference. While Tiffany, etc. use the 95/5ruthenium, Victor Canera, Caysie van Bebber, Mark Morrell and other custom ring makers use the 90/10iridium.

You absolutely will not want to polish your ring every year, and you likely would never polish a halo. A patina develops when the metal is rubbing against something, and a halo shouldn't be rubbing against anything. If you polish gold, it will wear away. You certainly wouldn't polish the milgrain of the platinum. You actually can ask them to rhodium plate the platinum when they make it, if high shine is very important to you. My e-ring shank is 90/10iridum and it hasn't been polished in 5 years and looks fine. But I take my rings off before doing things like housework or cooking, etc.

 

[justpeachy]

@yssie thanks for the input- I was pretty sure there wasn't a rhodium mix but second guessed myself lol. I'm just assuming they misspoke! & yes I've come to learn that my skin tends to wear off the rhodium plating on WG extremely fast, part of the reason I'm switching over to plat this time around even though the bright white of a freshly dipped ring is my fave

@chappy thanks for the visuals! I wonder if the pt950 looks more polished because it is less prone to scratches from being slightly harder? I'm definitely more drawn to the pt950 piece

@sledge i have quietly followed along on your e-ring design. so cool! that thread was one i pored over for info, so thanks!

@diamondseeker2006 i didn't realize rhodium plating it was an option, good to know! that might be good for me. CVB is who is doing it and gave me those two options so apparently she works with both!

 

[sledge]

@sledge i have quietly followed along on your e-ring design. so cool! that thread was one i pored over for info, so thanks!

Very cool. I had no idea that thread had helped you but I am glad!

If you like the shiny you might ask CvB if she does the WG/palladium alloy. Supposedly the best of both worlds. Shiny and no eating away like traditional WG with rhodium plating.

And as @diamondseeker2006 mentioned, you can also rhodium plate platinum for more shine. I'm a guy so I may fall in the minority but I actually like how plat will patina over time. And on a ring style like yours i think that adds charm to the ring personally.

Good luck, and be sure to post lots of pics when it's done! It really does look awesome.

 

[WinkHPD]

In addition to the excellent info posted by those above, you may enjoy these photos and details.

https://www.pricescope.com/journal/overview_common_alloys_used_jewelry

That article was composed by PS old timer John Pollard, back when he was Education Director at Whiteflash (just kidding about the old timer comment John). I have always appreciated the clear and well-ordered information and photos.

There are detailed descriptions of each common platinum alloy which John sums up nicely.

Wink

 

[Johnbt]

"The alloy you want to avoid is PT 950/Ir."

I'm still confused about this because tensile strength measured in PSI doesn't provide the complete measure of any metal or alloy.

For all the bad recommendations this alloy receives, I'm surprised anyone uses it at all. Where are the complaints from retail customers; I would think the internet would be awash with complaints and pics of ugly failures given the large number of ring makers reported to be using this alloy.

Maybe the setting process involves enough cold working to harden the prongs more than the initial casting. I have no idea and certainly don't know who work hardens their products and who doesn't, just some experiences with other metals in other areas and some curiosity about jewelry manufacturing.

 

[yssie]

"The alloy you want to avoid is PT 950/Ir."

I'm still confused about this because tensile strength measured in PSI doesn't provide the complete measure of any metal or alloy.

For all the bad recommendations this alloy receives, I'm surprised anyone uses it at all. Where are the complaints from retail customers; I would think the internet would be awash with complaints and pics of ugly failures given the large number of ring makers reported to be using this alloy.

Maybe the setting process involves enough cold working to harden the prongs more than the initial casting. I have no idea and certainly don't know who work hardens their products and who doesn't, just some experiences with other metals in other areas and some curiosity about jewelry manufacturing.

Re. Patina - Vickers.

Re. Production - certainly method of manufacture and work hardening come into play... and certainly the goal is not “strength” defined by topping the charts in all measures - ductility is only one consideration. Ductility, malleability, brittleness, machineability, scratch-resistance...

In general it is true that some metals and some modes of fabrication are theoretically more ideal for some purposes; in practice trusted jeweller preference and recommendation should always supercede theory - I have learnt this the hard way.

Re. The ubiquitousness of PT 950/Ir - even the big houses use it - it isn’t “bad”. There are alternatives for people who prefer to prolong high polish for as long as possible (all alloys of gold/plat will eventually patina, no exceptions). The general public knows that ‘platinum patinas quickly’, and that ‘WG yellows with age’, and I think it simply doesn’t occur to most people to try to find alloys that mitigate or altogether eliminate those characteristics...