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95% platinum/ruth


Hi folks, I just received a flier from Hoover and Strong stating
that over the next several months they will be converting the
bulk of their findings, shanks, etc to 95% Plat/ruth from their
previous stock of 90% Plat/Irid. They’ll also be adding a full
line of sheet, wire, etc in 95%. I’ve only been working with
platinum for a couple of years and solely in 90% plat/iridium. It
was my understanding that in the US this was the industry
"standard" I’m wondering if this shift by Hoover and Strong is
signaling a wider change. I’m considering scrapping/exchanging
the 90% I’ve got that is in raw materials and changing over to
the 95%. I only have a couple of finished pieces in my store
inventory -everything else has been special orders. I thought it
would make sense to stick with only one platinum alloy and now
would be a relatively simple time to switch -inventorily
speaking. I’d be interested in hearing what other people know/
think about any of the above. In addition, the notice from Hoover
states that the working characteristics of the two alloys are
very similar. Does anyone have experience with the 95% or with
both for comparison info? What are the differences or important
things to know or do differently . Thanks for any feedback.

Sumiche Handwrought Jewelry
Creating what you want in gold, platinum and silver


I have been using 95/5 plat/ruth for six, maybe eight or twelve
months, now. I first bought it because he was out of 90/10
plat/irid that day and suggested that it was a little cheaper. I
have noticed that there is a little more cracking if one is too
hasty but overall it makes a very nice alloy. It seems to be a
little softer, but also seems to be quite a bit easier to
polish. I think that it is probably a strong point that 95%
platinum may be marked “PLATINUM”. I much prefer it over the
cobalt platinum alloys.

Bruce D. Holmgrain
Maryland’s first JA certified Master Bench Jeweler



I don’t think you will notice the difference as far as welding
and polishing. I think the 95% plat/ruth polishes a little
easier but only slightly. I used Quality Casting in NY for
platinum casting for a long time and they used the 95% plat
5%ruth. We would size with plat/irrid in a pinch and you
couldn’t see a thing. I now use MMD in MN and they primarily use
95% plat/co, that is something of a different animal, it
oxidizes when welded and is noticeably easier to polish. I am
under the impression that 95% platinum has become the standard
in Japan and elsewhere around the world, so this may be driving
the finding companies to change. I noticed that Keystone
findings did the same thing as Hoover and Strong last year.

Mark P.


The main reason Hoover is switching is probably related to new
stamping laws, that say you need to lable the 900 alloys as such,
which 950 alloys only neet a platinum mark, without a fineness
indication. As to working with the two, they work in a similar
manner. The ruthenium alloy is not quite as hard, but it casts a
little easier. You can easily mix the two alloys in a piece so
long as they are parts soldered to each other. I’d avoid
actually melting scraps of iridium platinum along with ruthenium
platinum, but other than keeping the scrap from the two alloys
seperate, I wouldn’t worry about using them both in the same
piece. This way, you simply use up your existing stock of
iridium alloy instead of having to take the loss on scrapping it
out. Or keep a little of it aside for those times when you want
the slightly better work hardened condition of the iridium

Peter Rowe



Plat/irr was the "standard for many years until plat/cobalt was
widly distributed by Stuller. I understand that plat/cobalt is
best for casting while irridium is best for smithing. The two do
not get along well and when Stuller came out with the cobalt I
was very concerned. Now you say H&S is switching to ruthinium?
I wonder why? I’ll be eager to hear from those more versed in
metalergy than myself.

Steve Klepinger