Question about welding

[jeffminsc]

hey guys, I was welding a bumper on my car trailer but I keep getting holes in my weld bead. I'm using a MIG welder with solid wire and mix gas (75/25) I am using an old hunk of metal that I had laying around. I think it must have a galvanized coating on it because it is not rusty and has been sitting outside. I ground it down to shinny metal before I started welding it. I hope someone can give me some advice because I sure am

 

[4x4junkie]

Tiny holes like bubbles in the bead?

That usually comes from contaminants on the metal you're welding (rust, moisture, paint, dirt, grease/oil, etc.), or your shielding gas isn't shielding the weld correctly (insufficient flow, or the wind blowing it away while you're welding).

Are you welding outside in the open?

 

[jeffminsc]

Yes like bubles in bead. I Have 30 cfm going and welding inside guess I didn't clean the old hunk of metal good enough. Its been a while since I welded so I might be the problem.

 

[Sasquatch_Ryda]

You do NOT need 30 cfm when welding inside....15-20 is more than enough

 

[yyc_tbird_sc]

Check the torch assembly. Make sure that everything in the gun is properly setup, and that the hose is properly seated into the base unit. I know I was getting porous welds for a bit and I couldn't figure it out. The hose had actually pushed itself out from sealing inside machine just enough to cause the gas to leak out inside the machine.

 

[jeffminsc]

Thanks for the advice. I turned up the CFM's to try and get a better weld i usually don't have it that high. I will check the lead to make sure nothing is wrong with it. I didn't think of that. I'll do that this weekend and we will see what happens.

 

[yyc_tbird_sc]

What kind of welder do you have? I have a Millermatic 211. The clamp that holds the torch assembly into the machine needs to be really tight...like almost to the point of needing pliers to loosen it.

 

[jeffminsc]

have a holbart 140 finshed welding today I guess it was not clean enough I cleaned the metal beter and no problems.

 

[99_3.0]

Rule of thumb with GMAW is that the metal can't ever be too clean. With SMAW its not as big of a concern but still important. The cleaner the base metal the easier it is to get a high quality weld.

 

[Destroyer000]

check the polarity of your leads. its different for gas welding vs flux welding.

 

[ecenur]

hey guys, I was welding a bumper on my car trailer but I keep getting holes in my weld bead. I'm using a MIG welder with solid wire and mix gas (75/25) I am using an old hunk of metal that I had laying around. I think it must have a galvanized coating on it because it is not rusty and has been sitting outside. I ground it down to shinny metal before I started welding it. I hope someone can give me some advice because I sure am

Make sure that your mig weld is set up properly, if you haven't been welding for a long time do a couple practice routines until you get back on track with it. Also, make sure that you have a certain amount of gas to keep the weld clean.

 

[that_one_guy]

You can actually have to much gas. 30 cfm is a little excessive for inside in a controlled environment.

 

[94xcab4x4]

Just like said before you can have to much gas. Also check for leaks. Im a by trade and when i have used wire machines in the field i have run into quit a few leaks. Also that galvanized stuff can be tricky to weld it is some times looks like it is all ground off but isn't.