Platinum ring markings

I have a mens platinum wedding band with the marking "W_Plat". I have
read that that "pt" or "plat" as well as "900" or "950" would identify
the purity of the ring. However I am baffeled by the "w" in this
marking. Can Anyone clear this up for me?

(Spivieguy1) wrote:

I have a mens platinum wedding band with the marking "W_Plat". I have
read that that "pt" or "plat" as well as "900" or "950" would identify
the purity of the ring. However I am baffeled by the "w" in this
marking. Can Anyone clear this up for me?

I'd guess the "W" is the makers hallmark, not part of the quality stamp. The "plat"
marking indicates that it is at least 95% platinum (the same as a 950 mark) if the maker
is fully adhereing to current law, but some folks also (and mistakenly) use that plain
"plat" mark for the commonly used 900 platinum, which is an alloy of 90 percent platinum
and 10 percent iridium. The 950 alloys (only 5 % alloy, the rest platinum) are often
cobalt alloys, a more recent type of alloy used mostly in casting. Other possibilities
are 5% ruthenium, 5% iridium (uncommon, as it's somewhat soft) and a few other less
likely (at least in the U.S.) alloys.

Peter

Peter W.. Rowe, wrote:
(snip)
and 10 percent iridium. The 950 alloys (only 5 % alloy, the rest platinum) are often
cobalt alloys, a more recent type of alloy used mostly in casting. Other possibilities
are 5% ruthenium, 5% iridium (uncommon, as it's somewhat soft) and a few other less
likely (at least in the U.S.) alloys.

Peter

You wouldn't happen to know which alloying metal Rio uses for their
comfort fit platinum rings would you? Just curious.
Todd

On Wed, 01 Dec 2004 07:56:38 -0800, in ôõ Todd Rich wrote:

You wouldn't happen to know which alloying metal Rio uses for their
comfort fit platinum rings would you? Just curious.
Todd

Not off the top of my head, no, I don't. But I'd guess you could answer that question
quickly enough with a phone call to Rio, if it matters to you.

There are, by the way, some instances when it's important to know which alloy one is
working with, since they sometimes have slightly different working properties. If you
have a good strong magnet handy, you can detect the cobalt platinum alloys easily
enough, since they are weakly attracted to a magnet, while other varieties are not.
The cobalt alloys are the ones you most commonly need to know about when working, as
their melting point is slightly lower than iridium or ruthenium alloys, and cobalt
platinum slightly oxidizes when you heat it to solder or weld.

Peter

Peter W.. Rowe, wrote:
On Wed, 01 Dec 2004 07:56:38 -0800, in =F4=07=F5 Todd Rich torin@panix.=
com wrote:

You wouldn't happen to know which alloying metal Rio uses for their=20
comfort fit platinum rings would you? Just curious.
Todd

Not off the top of my head, no, I don't. But I'd guess you could answer=
that question
quickly enough with a phone call to Rio, if it matters to you.=20=20

True, but I tend to hold onto questions like that until I'm ready to make=20
another order. It wasn't a big priority, as I'm not planning on doing any=
=20
work on my wedding band.

There are, by the way, some instances when it's important to know which =
alloy one is
working with, since they sometimes have slightly different working prope=
rties. If you
have a good strong magnet handy, you can detect the cobalt platinum allo=
ys easily
enough, since they are weakly attracted to a magnet, while other varieti=
es are not.
The cobalt alloys are the ones you most commonly need to know about when=
working, as
their melting point is slightly lower than iridium or ruthenium alloys, =
and cobalt
platinum slightly oxidizes when you heat it to solder or weld.

Well, the large (strong) magentic v-block we use at work to check slight=20
magnetisim in work-hardened 300 series stainless can't detect any in my=20
ring. Thanks for the tip.=20=20

Peter

Todd