Friday, 13 September 2013

Scratch Start TIG Electrode Problems

Scratch Start TIG Electrode Problems - Intro


After reading up on TIG welding for a couiple of weeks I finally got around to buying some pure argon and unwrapping the welder. I thought TIG welding would be a tricky process, but by opting for a scrath start machine I think I may have bitten of more than I can chew. Here are some of the problems I have encountered.

Scratch Start TIG Electrode Problems - Electrode Keeps Melting


I was expecting the tungsten Scratch Start TIG electrode to last for ages so after melting the whole thing over a series of small welds I was confused as to what I was doing wrong. After stricking an arc the tungsten Scratch Start TIG electrode would remain in good shape for 2 or 3 cm of weld and then after a fizzling noise the arc stops and you find the tungsten electriode has melted.

Accoridng to the numerous guides avaialable there are number of reasons this can happen, the first being that you gas flow is too low. It should be set betweeen 6 and 10 litres per minute. But even with gas flows of 10 litres per minute I was still see the tungsten melt.

This was helped by sawpping Scratch Start TIG electrode type from ceriated to lanthanated, and also incrasing eltrode diameter from 1.6mm to 2.4mm. I also swapped up a cup size for the gas lense, which I hoped would reduce reflected / radiated heat from the cup. Results - this has helped greatly.


Scratch Start TIG Electrode Problems - Electode keeps "balling up"


Everyone tells me it is imprtant to keep the Scratch Start TIG electrode tip sharp, but I just can't seem to make this happen. After sharpening the Scratch Start TIG electrode will last a few seconds before balling up on the tip, and I am back where I started. If anyone has a solution to this please post in the comments below.

Beginners Guide to Scrath Start TIG

Desktop Study

2 comments:

  1. Have you got the earth return and torch the right way round? It should be +ve earth and not -ve earth. If you get it the wrong way round, the tungsten will keep melting as soon as you strike an arc.

    Bit late now, but any TIG welder without HF start is pretty much useless. TIG is hard enough to master, without farting about trying to scratch start!

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  2. Thanks birchy, yes I was foolish buying such a pants welder.

    I have checked and the torch is negative, which is a shame I would have liked an easy fix. Sctrach starting is a real pain, especially with a non-dimming mask, like trying to pick up an ant wearing a blindfold! (oh whilst wearing gloves) :-)

    Thanks for the input.

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