[Sneap] gold O-rings

[Walter Augustyniak]

Fred,
    Making your own Gold O Ring is doable, albeit a challenge.
At Bell Labs, when I first learned that it was doable, I refused to believe 
it.
    But after some practice and a few tries, I met with success most of the 
time.
    We used a small pure H2 torch, with O2. The flame must be tiny.
Our Gold wire diam was ~1.5mm and O ring diam ~ 6 cm.
    We had to make a special holder for the piece. I'm sorry I don't have 
access to a scanner at this moment (since I am on vacation).
I'll try to describe. We used a round block of ordinary steel, with a 
shoulder machined along the top periphery. The Gold wire lay in
this shoulder. Then we provided a small cutout along this shoulder, ~ 1 cm 
wide, to alllow clearance for the H2 flame. The wire was
bent into a loop (for the finished diam), but the secret was to have the 
clean cleaved butt edge under a very slight positive "load", (or
pressure) against the opposing butt.
    The tiny flame was brought in contact with the butt, held therefor just 
~10 sec or so, until the Gold melted and flowed neatly
across the joint due to the surface tension in the melt. If the butt 
pressure was too great, the resulting fusion looked like a bulge.
If the butt pressure was too weak, then the fusion resulted in a 
"necked-down" joint. This resulting section of the Gold wire is extremely
soft and will likely make a good vacuum joint even if it is not a perfect 
diam. I took pleasure in trying many times until I got it perfect.
    Good luck

        Walt Augustyniak
          Dep't of  Physics & Astronomy
            Vanderbilt Univ

----- Original Message ----- 
From: "Fred B. Bateman" <fbb at nist.gov>
To: <sneap at daytona.tunl.duke.edu>
Sent: Friday, December 15, 2006 11:59 AM
Subject: [Sneap] gold O-rings


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>
> Greetings,
>
> Does anyone know how to make a gold O-ring?  Does the gold wire have to be 
> fused together using a torch, or can it be soldered?
>
> Any assistance would be appreciated.
>
> Thanks,
>
> Fred Bateman
>
> Dr. Fred B. Bateman
> NIST Radiation Interactions and Dosimetry
> 100 Bureau Dr. Stop 8460
> Gaithersburg, MD  20899
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