Question about welding

jeffminsc · Aug 26, 2010

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 :icon_confused:

4x4junkie · Aug 26, 2010

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 · Aug 26, 2010

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 · Aug 26, 2010

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

yyc_tbird_sc · Aug 27, 2010

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 · Aug 27, 2010

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 · Aug 28, 2010

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 · Aug 28, 2010

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 · Aug 29, 2010

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 · Sep 6, 2010

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

ecenur · Oct 22, 2010

jeffminsc said:
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 · Nov 11, 2010

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

94xcab4x4 · Nov 25, 2010

Just like said before you can have to much gas. Also check for leaks. Im a :icon_welder:

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.

Question about welding

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