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Judging weld penetration

Posted: Sat Feb 06, 2016 5:07 pm
by Chrisjw1983
I'm very much still learning how to TIG but enjoying it and starting to dip the tungsten less...

I'm struggling with judging how well the puddle has penetrated before moving. Example, doing a butt weld with 1.5mm 304 stainless. I can get a puddle and dab pattern going but then I inspect the other side I'm inconsistently achieving full penetration. Any tips? Puddle width, etc?

Re: Judging weld penetration

Posted: Sat Feb 06, 2016 5:19 pm
by TigMonster
Can you show pictures?

Sent from my SM-G920P using Tapatalk

Re: Judging weld penetration

Posted: Sat Feb 06, 2016 5:25 pm
by Chrisjw1983
Sadly not. The brackets I was welding are now installed...

Essentially on the back side the two halves of the weld were not fused together.

Re: Judging weld penetration

Posted: Sat Feb 06, 2016 7:27 pm
by weldin mike 27
Im not sure if it transfers over to ss, but Jody had a video about butt welding Alum. Basically it's not move,dipe,move,dip,move...it's dip,move,pause,dip,move,pause...Only for a fraction of a second each pause, especially on your 1.5mm as it wont take much to burn through.

Its a practice thing, you'll get there.

Mick

Re: Judging weld penetration

Posted: Sat Feb 06, 2016 7:57 pm
by AKweldshop
You tell the penetration and fusion from behind the helmet.

Re: Judging weld penetration

Posted: Sat Feb 06, 2016 8:13 pm
by LtBadd
Chrisjw1983 wrote:I'm very much still learning how to TIG but enjoying it and starting to dip the tungsten less...

I'm struggling with judging how well the puddle has penetrated before moving. Example, doing a butt weld with 1.5mm 304 stainless. I can get a puddle and dab pattern going but then I inspect the other side I'm inconsistently achieving full penetration. Any tips? Puddle width, etc?
This will simply take hood time, the torch angle, travel speed, addition of filler, and amperage are all variables that you'll need to deal with. If you're not getting penetration then increase the amps and try again, make small changes and you'll zero in on achieving full penetration.

Also if you don't have a fixture to provide gas backing the weld will behave differently.

Re: Judging weld penetration

Posted: Sat Feb 06, 2016 11:06 pm
by Otto Nobedder
The sanitary-weld guys will tell you about the "devil's eye". The same applies to a root pass... There's a li'l swirly thing on the top of the puddle around your arc. How big the swirl is depends on how deep you're penetrating... When the top of the puddle is a "mound", the swirl is tight and close. As the puddle penetrates, the swirl gets bigger. This is one way to gauge how deep your weld has penetrated.

Steve S

Re: Judging weld penetration

Posted: Sat Feb 06, 2016 11:09 pm
by big gear head
Sometimes full penetration on stainless is not a good thing. If you don't have a back purge or something to prevent contamination on the back side then it can become a mess. If you have access to the back side then it might be better to weld both sides instead of trying to get all the way through from one side.

Aluminum and steel don't have the same problem as stainless steel. You can get full penetration on these materials without as much contamination on the back side.