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Working with Platinum & a microscope electric zoom


#1

Hi all I have been following this list with gratitude for a year or
so… learning allot. Being completely broke just now, I found myself
in a bit of a funny position of having to use Platinum, instead of
[buying] gold… Haven’t worked with platinum before mainly because
here in an Indian city, where my studio is these last years,
platinum is not readily available. I have a couple of grams of pt900
left off a 'commercial Diamond ring [I used the Diamond for a nice ring some years back] I want to use the platinum to make a bezel for
an 18k ring. Now, I have no Pt. solder, but going through the Orchid
archives, I read that it is possible to just use a thin piece of the
same alloy just to close-solder the bezel, I have the Little-torch
with butane-oxy, and expecting this is ok. I also have a tungsten
pick. my Question aRe:

  1. will the basic white powder flux [don’t know the name but it is
    from the west…] would do ? Can’t get anything else just now.

  2. I heard something about Iron contamination? I do need to roll the
    Pt and form it, probably melt it, and roll, hammer, and anneal
    … how do I clean the Pt from the Iron traces?

  3. is the normal Sodium-bisulphate pickle ok for Pt?

  4. is the regular ceramic crucible ok for Pt?

5] anything else I need to know…?

Many thanks and here also something perhaps helpful yet non
related… to share. Recently i have improvised a foot controlled
electric zoom for the bench microscope!, It is a real wonderful
technical benefit, as you can keep your hands on the shifting work
and stay in focus. you can make it your self ! If anyone is
interested, I can put on a photo and explain the solutions I came up
with…

Love & Light
akash
www.akashjewels.com


#2

Akash,

You will find that there are some real benefits with working with
platinum, but only if you are prepared to work with under it’s
terms. You may need solder. Platinum that is alloyed with non
platinum based metal will have a lower melt temp than platinum group
metals and will not fuse well. You will need a special high heat
crucible and some welders goggles.

To your questions:

ill the basic white powder flux [don't know the name but it is from
the west...] would do ? Can't get anything else just now. 

Don’t use flux. Make sure your metal is clean. The high melting
temperature of platinum will contaminate the metal causing it to
become brittle. You don’t need it anyway as platinum group metals
don’t oxidize. If you have metal that is alloyed with cobalt you
won’t be able to fuse weld in the manner you are thinking. You can
tell because it will oxidize and is slightly magnetic at room
temperature. If you are able to get some platinum solder and wish
to proceed then after you finish your soldering you can coat the
metal with boric acid powder, anneal it and pickle it. The
oxidation will come off in the pickle.

I heard something about Iron contamination? I do need to roll the
Pt and form it,  probably melt it, and  roll, hammer,  and anneal
... how do I clean the Pt from the Iron traces?

Soaking the metal in pickle will remove any traces of iron. If your
pickle is old and you have a great deal of contamination you can get
some copper plated onto the metal, so use new pickle to remove the
iron. Lots of things can contaminate platinum, not just metals.
Acetylene will contaminate platinum as it contains so much carbon
that it actually fuses to the metal at the solder joint making it
brittle. Butane should be OK as it is relatively lower in carbon

is the normal Sodium-bisulphate pickle ok for Pt? 

Yes.

    Is the regular ceramic crucible ok for Pt? 

No. You will need a high temperature crucible. The regular gold
crucibles will break down at the temperatures needed for melting
platinum and contaminate the metal.

anything else I need to know....? 

One thing you don’t mention is the need for eye protection. You
absolutely must wear welders goggles when you weld platinum. The
metal emits a great deal of ultraviolet light that will cause damage
to your vision. Don’t use sunglasses, only goggles meant for
welding. By the way, if you ever do a great deal of platinum work
you may also be interested in creating a shield that will cover your
entire face. The ultraviolet will actually give you a burn if you
are torch melting a lot of platinum or even a little if kept at a
melting temperature for a sustained period of time. This actually
happened to me years ago when I was making my own platinum wire for
a series of wedding and engagement rings (platinum was a lot cheaper
then).

Larry


#3

Akash: First I would love to see the motorized electric zoom for your
microscope. I have been contemplating the very same thing so maybe I
can save some time and energy with what you have done. Platinum
Questions. I leave those answers to those a little more qualified.
Frank Goss


#4

Hello Frank and anyone else interested to make a motorized zoom. I
have just uploaded a page with a couple of photos and some details
of the microscope motorized foot controlled zoom thing.

It’s on this URL:

http://www.akashjewels.com/electricZoom4microscope.htm

Thanks allot for the instructions on Platinum welding, I would have
never guest the thing about not using flux. Neither would I think to
use goggles… I will try tomorrow.

I asked about which crucible to use, and I meant more to ask on
which surface to work upon, as I only need to melt a couple of
grams… Looking through a Swiss catalogue, I saw the crucibles I do
have here. These are called ‘Sillimanit’ and they also sell a
soldering sheet for Platinum, that is made of the same ‘Sillimanit’.
So I assume that I can simply use the flat back of the crucible, as a
soldering base?

And one last thing… I received two opposite responses to the
question about using the regular bisulphate pickle for platinum
{perhaps my misunderstanding] But Larry wrote to use the clean
pickle, and Mark wrote that it is not ok to use…? may I ask
again; Do I use the pickle, ? Or is it that the pickle is used only
for cleaning from contamination before welding, and after there’s no
need for Pt does not oxidized and there is no flux to clean
either…? Got safety welders goggles for 75 Rs, about … 1.5$
[‘best quality’ with German made glass] India is so very wonderful,
It’s ‘Diwali’ night tonight, everything explodes all around with
colours and loud bangs.

Love & Light
akash
www.akashjewels.com