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Old 06-29-2018, 04:20 AM
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neilb neilb is offline
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Default dc tig mild steel

i'm having a little trouble with my tig, it welds as though there is no gas, the electrode burns up like it would as if the gas was off. i do have gas flow, pre - during - post welding. doesn't matter which type of electrode i use lanthanated, ceriated, zirconated. i have a gas lens fitted, i recently fitted a gas dryer in the feed line in case of moisture. i'm using and have always used argon/co2 mix, i only weld mild steel. machine is a uni mig 200 a/c

anyone have any ideas? i'm about to change to pure argon just to try it
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Old 06-29-2018, 04:32 AM
2lateagain 2lateagain is offline
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Have you got the polarity around the right way for TIG, positive to earth.


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Old 06-29-2018, 04:58 AM
Bevelhead Bevelhead is offline
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Dead give away for burning back is incorrect polarity. Also check the lens is not contaminated with spatter
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Old 06-29-2018, 05:27 AM
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thanks for the quick reply guy's

i can definately say the polarity is correct, i've had this tig about 6 years now and it's only recently it's started to weld like crap lol. i shall check the gas lens and maybe try another. it doesn't get used much to be honest, probably an hour of welding a month at most. so it's hard to pin point when and what, if anything occured when it started going wrong (gas lens fitted, new bottle of gas)
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Old 06-29-2018, 06:03 AM
hot rivet hot rivet is online now
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If you are tig welding steel with anything other than argon you are going to have problems, CO2 is not an inert gas and that will be part of your problem. From experience tig ceramics will absorb moisture and other chemicals even when they appear dry they can outgas whatever it is they absorbed. Poor storage of you torch may have caused the gas pipe to collapse / get pin holes either restricting gas flow or allowing air in. The other very common problem is bad earth due to cable breakage or clamp making poor contact (arced surfaces)
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Last edited by hot rivet; 06-29-2018 at 06:25 AM.
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Old 06-29-2018, 10:13 AM
mastuart mastuart is offline
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You need argon for tig.
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Old 06-29-2018, 03:06 PM
Turbo57 Turbo57 is offline
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I think pure argon is better for stainless steel i have more prob when i weld mild steel with that, i dont know what the name is in your country but here it is called Mison and and that is argon with co2, your problem must be something other not the gas
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Old 06-29-2018, 04:31 PM
hot rivet hot rivet is online now
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The problem is almost certainly the co2 it breaks down in the arc to form carbon monoxide and oxygen- the oxygen reacts with the tungsten and the steel = porosity and dirty tungsten.
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Old 06-29-2018, 04:43 PM
norson norson is offline
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Even though you are sure.... double check the polarity. I had the same things happening and that was the problem.
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Old 06-29-2018, 05:12 PM
Gareth Davies Gareth Davies is offline
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The gas hose sometimes splits inside the handle, due to the amount of manipulation, and this can allow air to get dragged in. Itís an easy one to check.
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