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Re: Use of unsealed thorium in TIG Welding



Yes, yes, yes.  Thoriated welding rods are made by several manufacturers.  They
are easy to spot because they are clearly marked thoriated with the percentage
(either 1% or 2%), as opposed to tungsten or zirconium-tungsten.  What I still
want to know is who makes aluminium oxide grinding wheels using thorium?  I have
never seen a grinding wheel marked either "thoriated" or "radioactive."  Is this
hearsay or does someone have some facts to back it up?

bill
bkolb@arinc.com 
_______________________________________________________________________________
Subject: Use of unsealed thorium in TIG Welding
From:    radsafe@romulus.ehs.uiuc.edu at smtpgate
Date:    5/13/96  11:52 PM

To Radsafers:
>Could you be specific which manufacturers and which Aluminium Oxide
>wheels?  Are
>you sure the use of Thorium is intentional?
>
>bill
>bkolb@arinc.com
>_______________________________________________________________________________
>Subject: Re: Use of unsealed thorium
>From:    radsafe@romulus.ehs.uiuc.edu at smtpgate
>Date:    5/13/96  1:44 PM
>
>Some manufacturers use thorium in the constuction of aluminum oxide grinding
>wheels.  Tungsten welding TIG rods are sometimes thoriated also. Doug Turner

Coincidentally, I received a call yesterday from an RSO, Mr Iain Morrison,
in industry who has been shown "Thoriated" welding rods, and was getting
0.6 uSv/hr at the surface of the packet (gammas only.)  The small print on
the seal of the packet said "radioactive".

The rods are:
Thermadyne (TM)  Tweco (R) Tungsten electrodes, 10 each to a packet.
AWS Classification - EWTh-2, Ground Finish, 2% Thoriated Tungsten,
made in USA by Osram Sylvania Inc, Chemical & Metallurgical Products,
Towanda PA 18848.

The enclosed safety information was difficult to read, but stated the
material contained ThO-2, and then had a figure of 1 x 10*-12* uCi/ml.  (Is
this in the rod, or in the fumes generated?).

These TIG rods are obviously deliberately thoriated.  They have been used
"for hard facing for many years - as long as the workshop Engineer can
remember - they keep them locked up in a filing cabinet as they are
expen$ive!!"

Does anyone know why, and what would be the risk in using these in an
unventilated area?
 I understand that fumes from TIG welding are normally removed from the
work area by a suction line & vented outside.

Iain and I are very interested in any information that could be provided.
Thanks in advance.


---------------------------------oOOo-(_)-oOOo--------------------------
Byron McKavanagh,
Radiation Officer,
Department of Applied Physics,
Central Queensland University
Ph 079-309625                   Fax: 079-309209
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~)(~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Just remember you are unique.  Just like everyone else."
(Dictionary of Cynical Quotations, 1996 ed.)
The views expressed above are those of the author only, and if they are in
error, it's because i pressed "SEND" when i should have pressed "DELETE".
Oops!
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