Sharpening Tungsten Electrodes: A Personal Opinion
by Al Swilling
(Chattanooga, TN, USA)
I have been a machinery fabricator and welder (TIG, Stick, MIG) for 45 years, after spending the first four years of my life as my father's apprentice. I was 12 when I hired in as Dad's apprentice, and by age 16 I was a qualified machinery fabricator and welder, including stick (SMAW) and "heliarc" (TIG). MIG came later.
In my total of 49 years experience, I have worked in shops and on road crews that were well equipped; and I've worked in shops and on crews where the welder/fabricator had to furnish all his own tools, including grinders, drills, etc. Usually, though, there was always a bench grinder, usually with a green stone on one side and a coarser stone on the other. In such shops, most TIG welders used the bench grinder's green stone and a cup of water to grind their tungsten electrodes. I always used the flat face of the stone instead of the outer edge, which provided better sharpening and less vibration. The problem with a green stone is that they're soft and wear out relatively quickly--and usually aggravate the machinists who use the same stone to sharpen their carbide lathe tools.
If a bench grinder was not available, a hand grinder with an 80-120 grit sanding disc had to suffice. The problem with a hand held grinder was keeping it still enough to grind the tungsten. It's hard to grind a tungsten properly with one hand while holding a wobbly grinder with the other.
Somewhere along the line, I discovered Chem Sharp, or "Chemical Sharpener" as it was originally called. I tried a jar at the recommendation of the welding supply representative who serviced the company I was working for at the time. I have kept a jar of Chem Sharp in my tool chest ever since.
I like Chem Sharp for three reasons:
1. It does a great job of sharpening the electrodes;
2. If necessary, I can sharpen my electrodes without a grinder and without having to leave my work station or work area;
3. Chem Sharp sharpens tungsten electrodes faster than grinding, and requires very little effort.
There are other benefits to using Chem Sharp, but those listed here are why I personally like it as one electrode sharpening solution.
Soon after I began using Chem Sharp, I found a down side to using Chem Sharp; but it's up to the individual to determine if the down side outweighs the benefits.
The down side was apparent the first time I had to sharpen a tungsten that had picked up traces of filler rod on the tip. With a grinder, the user simply grinds away the contaminating metal and sharpens the tungsten underneath, with very little if any waste of tungsten. Chem Sharp sharpens the tungsten behind the contaminated area instead of eating through the contaminant, which causes some waste of tungsten.
I have found that electrodes sharpened with Chem Sharp seem to last a little longer than those ground with a grinder. That little bit of extra time saved, plus the shorter sharpening time per tungsten, add up over an 8 to 10 hour shift, especially when out on a job site where a bench or hand grinder might not be readily available or is inconvenient. It might even offset the cost of the little bit of wasted tungsten due to contamination.
I must also say that I think it is poor marketing on the part of Chem Sharp's makers to put it in a glass jar. I have a metal container with a screw-on lid to which I immediately transfer the Chem Sharp. The heat generated by the sharpening action has broken more than one glass jar. Then there's the problem of the jar being accidentally knocked off its perch and breaking on a concrete floor or steel catwalk. With a metal container, I don't have to worry about heat or its getting knocked off onto a hard surface.
Ideally, I prefer a bench grinder with a fine grit stone around 120 grit and a cup of water (if you've sharpened very many tungstens, you know what the water is for) for grinding tungsten electrodes. If a grinder is not easily available, or if time is a factor, I do not hesitate to use Chem Sharp. Unless someone can show me why Chem Sharp is a bad sharpening solution, I will continue to use it as my backup of choice.
Chattanooga, TN, USA