What is the best platinum blend?

[kolodcaj]

What is the best platinum blend that will offer the most stability, durability and shine?

 

[kolodcaj]

Any help out there?

 

[Gator]

I've heard of many people liking the 90% platinum and 10% iriduim mix. Most benchworkers seem to like this mix more as it is easier to work with. It is also very durable- lesslikely to scratch than 95% platinum.

 

[TheDiamondangel]

Actually, from what I understand, the 90/10 iridium mix is harder to work with. However, for engraved pieces it's the best choice. The engraving will stay sharper longer.

Many major manufactors use the 950 PT with cobolt. Those pieces wind up looking burnished very quickly. I'm sure there are other mixes out there. Perhaps some of the experts will chime in here.

 

[Hest88]

From what I've seen, most decent platinum wedding rings seem to made out of 95% Plat/5% Ruthenium. That should work fine for an everyday ring. However, as DA said, the 90 Plat/10 Irid is a harder alloy and I was hoping to get that mix for my DH's wedding ring. From the research I was doing, it would be a mix I would really want for anything with intricate engraving. (You don't want to get 95 Plat/5 Irid because it's really soft.) There is also a special alloy called Platinum-S (or something like that) that Stephen Kretchmer developed especially for his tension rings, so I don't know how widely available that is.

Whatever you do, stay away from a cobalt alloy. Cobalt is hard, but notoriously brittle.

 

[canadianice]

95% Platinum, 5% Ruthenium has a base Vickers hardness (HV) of 130-135 (up to 210 if die-struck). This is the Platinum Guild's preferred formulation for jewellery and is pretty commmon in North America.

95% Platinum, 5% Iridium is softer with a base HV of 80.

90% Platinum, 10% Iridium is the most popular formulation in the US, with a base HV of 110-115.

Any jewellery with at least 95% Pt will be stamped PLATINUM, PLAT or PT950. Lower formulations are denoted with the alloy, such as IRIDPLAT.

Note HV is hardness, not necessarily strength. Platinum is inherently a very strong metal (base HV 50).

Here's a couple links for info:
http://www.preciousplatinum.com
http://www.platinum-wedding-rings.com/platinum_alloy_information.html