Porosity With Tig On Mild Steel.

It is a good idea to purge the air from the hoses. If my rig has been unused for a while, I have gotten porosity in the first inch or so of a bead. It is a good idea to push the pedal a couple of times to purge air from the lines before striking an arc.
 
Possibly a "lower" grade of steel. Many years ago a friend wanted to fabricate a 40 gallon gasoline storage tank, he purchased the metal ( 14 ga) and I got the job of TIG welding the seams.... Holy piece of crap, whats happening? Went to work next day, talked to Jim ( the most knowledgeable welder around and my mentor) first words out of his mouth were rimmed or killed steel. I ended up stick welding ( 6010 & 7018) the seams.... Google "Rimmed or Killed Steel" wealth of information there. Hope this helps.

Bill
 
Mill scale.
Next time you get to the steel yard ask to see a piece of Hot Rolled (HR) and a piece of Cold Rolled (CR). The HR has scales like a fish, while the CR is relatively shiny.
HR is rolled to its final size while hot enough to scale (over about 1700 degrees F). CR is rolled to size below scaling temperatures.
HR also seems to be oily. I don't know that it is.

Daryl
MN
 
most of my tig welding is done with 2.4 mm tungsten and .6 mm,.9mm and 1.2 mm 316 mig wire,it is not very often the I have to use 1mm tungsten but I do when material is like paper thin...and like wise with wire..rarely do I use 1.6 mm wire or heavier unless the material is over about 5 mm...the thinner wire is a lot easier to use on thinner material...I do not have any golden rule on how I sharpen my tungsten other than to hold it vertical when sharpening against wheel..this keeps impurities to a minimum from grinding wheel..the point of the tungsten tapers back about 6mm...I have worked in stainless industry for many years and these are the basic guide lines that I have always stuck by...clem
 
I'm sold, stainless rods on mild steel from now on.
The welder, three in one chinese welder
welder1.jpg
welder2.jpg

The rods
rods2.jpg
rods1.jpg
The welds
1, mild steel on cleaned metal
2, mild steel on uncleaned metal
3, no filler just fusion on cleaned
4, stainless on cleaned
welds1.jpg

5, stainless high amps on uncleaned
6, mild steel low amps on uncleaned
7, mild steel high amps on uncleaned
8, stainless edge bead on cleaned
This should be flipped as 5,6,7 were welded right to left
All welds were pos earth

welds2.jpg
 
are you sure you are getting gas out? should look way better than that
 
What do you get with no filler? Just run a puddle across that sample. Metal cleaned.
 
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