If you bought a gas lens kit, or even if you are just using collet bodies and standard ceramic cups, you will need to adjust your tungsten electrode extension from the end of the cup to suit your situation and to provide adequate inert gas coverage around the molten metal pool.  Initially this may seem somewhat arbitrary, but there are rules of thumb that people rely upon to give them good results.  These rules no doubt came about via experience, but what is the reason behind different lengths and extensions or stick-out?

This is a short video that shows how to set up a ceramic or glass cup with a gas lens diffuser, and gives you the basic rule for determining maximum stick-out.  

Here is a video that provides some insight into how experienced welders use those rules and adds the flow rate variable into the setup.

You can purchase various depth gauges for tungsten stick-out, or make your own.  They generally consist of a block of metal drilled to various depths for different diameter cups.  The rule of thumb is that the maximum stick-out should be the inner diameter of the cup.

Cup sizes are numbered in 1/16 inch increments, so a #4 cup is 4/16 inch, up to size 24, which is 24/16 inch.  That means your maximum stick-out would be easily determined by the cup size inner diameter. 

An easy way to achieve that is to use a vernier caliper.  Simply measure the inner diameter with the caliper prongs and then hold one prong against the cup edge, letting the tungsten protrude to the other prong.  For cup sizes wider than the prong extension, you could use the depth rod on the end of the caliper.  Position the point of the tungsten on the base of the caliper beam and sight across the cup edges, making the depth rod match the sight line.

Last modified: Saturday, 27 July 2024, 8:34 AM