Thoriated-tungsten is pointed accurately and quickly by using sodium nitrite. Point produced is smooth and no effort is necessary to hold the tungsten rod concentric. The chemically produced point can be used several times longer than ground points. This method reduces time and cost of preparing tungsten electrodes

Ziegelmeier, P.

English

NASA Technical Reports Server

March 1971	 Brief 71-10048 
• ,W co
AEC-NASA TECH BRIEF 
rES	 AEC Headquarters 
AEC-NASA Tech Briefs announce new technology derived from the research and development program of the U.S. 
AEC or from AEC-NASA interagency efforts. They are issued to encourage commercial application. Tech Briefs are 
available on a subscription basis from the National Technical Information Service, Springfield, Virginia 22151. Requests 
for individual copies or questions relating to the Tech Brief program may be directed to the Technology Utilization 
Office, NASA, Code KT, Washington, D.C. 20546. 
Accurate Pointing of Tungsten Welding Electrodes 
The problem: 
To develop a method for pointing tungsten elec-
trodes for tungsten-inert gas (TIG) welding. 
The solution: 
The thoriated-tungsten used in the automatic TIG 
welding process can be pointed very accurately and 
quickly by using sodium nitrite (NaNO2). Unlike the 
results obtained with grinding techniques, the point 
produced is smooth and no effort is necessary to hold 
the tungsten rod concentric. This sodium nitrite proc-
ess takes 1/10 the time required for diamond wheel 
grinding and one can become proficient with very 
little practice. In addition, the chemically produced 
point can be used several times longer than ground 
points. 
How it's done: 
The thoriated-tungsten electrode rod is chucked 
(hand tight) in a drill press or similar device to rotate 
the rod in a vertical position. A slow rotation speed is 
necessary. 
A torch is used to heat the end of the tungsten rod 
until it is red. The sodium nitrite in stick form is then 
touched to the heated rod and the point is produced. 
The chemical reaction caused by contact of the heated 
rod with the sodium nitrite keeps the rod red hot.
Notes: 
1. This information may be of interest to the welding 
industry. The method reduces time and cost of 
preparing tungsten electrodes compared to con-
ventional grinding techniques. 
2. Requests for further information may be directed 
to:
Technology Utilization Officer 
Division of Technical Information 
AEC Headquarters 
Washington, D.C. 20545 
Reference: B71-10048 
Patent status: 
Inquiries about obtaining rights for the commercial 
use Qf this invention may be made to: 
Technology Utilization Officer 
Division of Technical Information 
AEC Headquarters 
Washington, D.C. 20545
Source: P. Ziegelmeier 
Central Shops 
(A RG- 10449) 
Category 08 
This document was prepared under the sponsorship of the Atomic 
Energy Commission and/or the National Aeronautics and Space 
Administration. Neither the United States Government nor any per-
son acting on behalf of the United States Government assumes any
liability resulting from the use of the information contained in this 
document, or warrants that the use of any information, apparatus, 
method, or process disclosed in this document may not infringe pri-
vately owned rights.
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Accurate pointing of tungsten welding electrodes

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