Guy told me I need to preheat the starting point of every MIG weld before welding.
?????
Is this true? Never heard it before.
Talking about plain old mild steel here.
- Chips O'Toole
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I was socially distant before it was cool.
I drop a few tacks along the length, small enough to be certain I can consume them with the weld bead. This often puts enough heat into the piece to insure the starting point of the base metal is hot enough.
The issue is MIG is short circuit. The first 1/4"->1/2" of your weld, the base metal is heating up. Unlike TIG or Stick where you can control your feed and bead and travel speed, MIG is slinging wire when the button is pressed. So, press the button, take of running else you have a WAD of weld.
The issue is MIG is short circuit. The first 1/4"->1/2" of your weld, the base metal is heating up. Unlike TIG or Stick where you can control your feed and bead and travel speed, MIG is slinging wire when the button is pressed. So, press the button, take of running else you have a WAD of weld.
A nice article about preheat
http://weldinganswers.com/preheat-and-i ... al-steels/
http://weldinganswers.com/preheat-and-i ... al-steels/
I have more questions than answers
Josh
Josh
Correct me if I'm wrong, but that article is for steel that has sufficient carbon content that the formation of martensite would be problematic. Plain mild steel wouldnt have enough carbon content (<0.30%) for that issue.Poland308 wrote:A nice article about preheat
http://weldinganswers.com/preheat-and-i ... al-steels/
- Chips O'Toole
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The project I'm currently working on is 1/8" tubing.
I was socially distant before it was cool.
Unless the specific goal/intention of the pre-heat is disclosed, I would say that 99.9% of people would not bother with pre-heat on MIG'ing mild steel anything. Pretty sure we all get decent MIG welds on mild steel without pre-heat, so long as the part thickness/joint configuration are within the capabilities of the machine and the operator has the skill/know-how to carry out a sound weld.
- Chips O'Toole
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The welds on this project have areas where they could be more beautiful, but I can't see any difference between the starting points and the rest of the welds. If the starting points have imperfections, I think they're lost among the much larger imperfections resulting from lack of skill.
I was socially distant before it was cool.
thats probably where it all comes from. using marginal machines.Oscar wrote:........... steel anything. Pretty sure we all get decent MIG welds on mild steel without pre-heat, so long as the part thickness/joint configuration are within the capabilities of the machine .......
tweak it until it breaks