I repaired some brackets today on a friend's riding lawnmower, using angle iron for patches. I have a 110v 145 amp mig, with a c02/ar bottle. I am happy with my penetration, but I think my technique is lacking. I am doing simple fillet welds, and moving the tip of the gun side to side as I move down the weld, to make sure I get good penetration on both the base metal and the angle iron patch.
Here's a link to a page with a bunch of pictures of the welds:
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Closeups of the beads are here and here:
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The welds passed the hammer test, and the jumping up and down on them test, and the cutting grass test. I just wish they looked better. Any suggestions?
Too much metal on there. So much it actually looks like it is dripping. And it looks pretty hot.
You could probably use those settings and get a prettier looking weld by doing figure 8s and keep overlapping them, running from mower to patch.
You got waay too much metal in the puddle.
What you got is called a "gorilla weld". Probably stronger than the surrounding metal, and will last forever, but needs to be a little prettier. Too many starts and stops, too.
What Steve said. I think you could have cleaned your material better, looks like some porosity in the bottom area of the 4277 picture- where there's three little hills that all look alike, also the upper right corner. If you ground them I think they'd be porous, it looks like you have adequate shield so I figure it's unclean base metal.
Looking at the second picture, there's points where it looks good, but again the lack of cleaning is working against you.
Practice. You're keeping your gas in place, that's good. Work on seeing the puddle and travelling consistently. I honestly believe that the little migs are more difficult to do nice looking work with, at least that's been my experience, and once you get doing a good job with this one and move to a bigger machine you'll be very pleased with the work you can do.
I think it was Steve who made the point recently that you should run your tool over the joint a few times (like a golfer taking practice swings) to be sure it's positioned so that's it comfortable to work with and to familiarize yourself with what you're doing. It's hard to do good work when you're not comfortable- it's certainly not impossible but it sure adds to the problems you don't need.
When you're fitting your work, try to make the joints as consistent as possible- your machine settings and travel speed rely on the joint fitting, and if the fitting varies it makes the job harder. One spot will need less heat and you'll burn through, then you hit a spot where you need more heat and it's difficult. If you hit a point where you see the heat spreading faster than you like, pull the gun back a bit and the extra stickout will reduce the heat you put into the work. On thin stuff you're better off travelling fast and hot- if you try to go slow because it's thin the heat will spread and a big hole will fall out.
Tailor the thickness of your weld to the thickness of the base metal. A weld that stands up too high will concentrate stress at a point in the base metal very near the edge of the bead and failure will occur.
Thanks for two great replies. I like the "gorilla weld" term. I'm going to use the figure 8 technique, use less metal, adjust my stickout instead of always keeping the same distance, and work on my fitting and cleaning. I'm sure Alex will break something else soon, so I'll get to fix that and try all these things. He runs a state-funded summer camp, so their equipment is all old and heavily used hand-me-downs, and it's a lot easier for me to do a quick welding fix than for him to wait months until he can get the state to send someone out to fix it.
As far as the 110v mig, I bought it when I lived in place that only had
110. I could go to 220v now, but Alex's shop only has 110v anyway, so this was the right tool for the job.
I did take a class at the local vocational school about three years ago, when I first got serious about welding. It paid for itself the first night, when I learned how to adjust a torch to have a neutral flame. I had been trying to do that for months. Some things you just can't learn from a book.
The rest of the class was mostly a waste for me. I have a tig and mig and wanted to learn how to use them better, but the instructor had everyone doing stick for most of the semester. He felt it was a good foundation. Plus he was mostly interested in teaching the vocational students so they could get jobs. He didn't have much time for us dabblers. He had lots of good safety stories, though. I will never, ever cut into a tank with a torch.
I would like to spend time with real welders, but most of the people I know are more interested in playing golf and mowing their lawn.
By looking at the pix, the fitment and crud on the deck aren't suited for shielding gas mig process. I would have chosen flux core wire for job. Little smoke and splatter but would do a good job and look decent also.
The rust and crud don't look terribly deep. I would have used an electric brush to clean them. Cleaning metal improves the weld properties immensely even on everyday welds. Particularly MIG. A few seconds, and you're down to bright metal.
Dave, they're not pretty but they sound strong. That's the main concern. When I'm welding this same sort of item I wire wheel the area to get rusty areas a little cleaner. Sometimes a slight grinding is needed. Instead of welding your bead in the direction of the joint (parallel with the patch) I start the weld on the base steel (the deck in this case) then drag to the left over the edge of the patch steel, then back to the deck and zig-zag the weld until I work down to the end of the patch. I would turn the wire feed down a bit so it doesn't look so globby. Here's a sample:
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that's how I would do it, but as long as it's a strong weld with good penetration, your weld is fine.
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