I am curious about how seriously to take the sharpening of TIG electrodes. First, I have been using my bench grinder which has seen service for all kinds of things including bronze, which is said to gum up in the abrasive (and contaminate the TIG electrode?). Do I need to purchase a dedicated grinder/sander for TIG electrodes? What about using just a piece of sandpaper (but isn't that aluminum oxide, which would also be a source of contamination)?
Also, I have seen quite a few sources which underscore that the electrodes need to be sharpened along the same axis as the length of the electrode, not across it. Why would this be? It *seems* to work either way... Finally, all the instructions say to make a small flat spot at the tip, but this doesn't seem to make much of a difference, either. For AC you're supposed to "make a ball" on the end which puzzled me until I found that the ball forms within seconds of starting to weld. As far as I can see, there is no reason to do anything to AC electrodes other than clean them.
If any of you folks out there have TIG electrode sharpening tips, I could sure use them!
Thanks,
Chris
first of all,sharpening your TIG electrodes on a "common" bench grinder will not adversly affect your welds,unless you intend welding something like the space shuttle!
The reason for sharpening along the same axis as the length is that when using lower currents,the arc ignites straight from the tip and doesnt try to "wind"itself down the point of the electrode.
The reason for the flat spot is;at lower current,it ensures the arc is initiated from the same point every time.this can be important when using automated processes,or pulsed TIG.
when welding with AC,make sure your electrode diameter is sufficient otherwise you risk the electrode overheating and being vapourised into the weld.
I've tried flatening the tip of the tungsten just a tiny bit just to see if it makes a difference like the new books and ads say. personally, i think it spreads the heat out too much. I like to point to where I want the heat and have it concentrated in a tiny area for small welds.
I agree, unless your using an orbital machine or a fully automated TIG machine,the average user is unlikely to notice the difference.
One more hint,if, when welding ali,the "ball" on the end of the tungsten is greater than the diameter of the actual tungsten,move up in size because this is a dead sure sign that your exceeding the currant capacity of the tungsten
Chris;
As far as tip prep for more or less penetration goes, many GTAW welders are misinformed.
Arc characteristics actually relate as follows: For a more directional penetrating arc you will need a more radical angle.
The long tapered tip will actually produce a more bell-shaped arc with shallow penetration. This style is useful for low amperage arc starting or build-ups on knife edges etc. There is a danger with this type of long taper of transference of the tip of the electrode into the pool with higher amperage arc starts.
The blunted tip helps to eliminate the danger of tungsten transfer and produces a more conical arc with better directional control. However, there is a penalty in arc starting performance.
Here is a link that explains what I am saying with accompanying diagrams of included angle Vs penetration.
http://www.pro-fusiononline.com/tungsten/geometry.htm
PS. There are quite a number of postings about GTAW electrodes for both AC and DCEN you might like to try the search function in the web-board to get even more info.
Thanks for all the geat responses. Lawrence, your post especially explains what I was observing. I had been making my electrode pointier in an effort to focus the arc. This would result in the opposite effect, which is counter-intuitive, and I thought that I was contaminating my electrode. Live and learn... thanks, y'all!
Chris
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