Hey guys, Im a self taught welder and kinda learn by doing. Sometimes I can make really nice looking welds and then the next bead will look like krud. I mean within minutes its like a three year old did the welding. I dont change the settings, wire speed, gas, or anything. Am I holding my mouth wrong, Thinking impure thoughts, did the planets mis-align. Im really baffled. See the pictures below for what Im talking about. These beads were done minutes apart. Oh, I weld with a miller-matic 135 mig welder. Its a little 125 amp 20% duty cycle machine. Any thoughts would be appreciated,,,,,,Thanks
Welding question.....HELP!!!!!
- Thread starter Hiltz
- Start date
- Views: 8218
Bill_C
Gold Member
What's your gas flow set at?
I'm certainly not an expert weldor like some folks, but I believe this is mostly a matter of moving the gun smoother. Maybe slow the wire speed down a hair and move slower, and support your gun hand on something. Also, on the upright piece on the right side of the second picture, your weld doesn't look like its got any penetration into the horizontal piece, looks like the gun was pointing too much towards the vertical piece. That's one drawback of the GMAW process, it can lay a bead that looks decent but actually isn't penetrating.
I'd work on how the angle of the gun as sell as holding the gun smoother. And try to move your work to make all the welds in the horizontal or flat position rather than vertical up or overhead. Here's some pointers I found that helped me http://www.millerwelds.com/pdf/mig_handbook.pdf
I'm certainly not an expert weldor like some folks, but I believe this is mostly a matter of moving the gun smoother. Maybe slow the wire speed down a hair and move slower, and support your gun hand on something. Also, on the upright piece on the right side of the second picture, your weld doesn't look like its got any penetration into the horizontal piece, looks like the gun was pointing too much towards the vertical piece. That's one drawback of the GMAW process, it can lay a bead that looks decent but actually isn't penetrating.
I'd work on how the angle of the gun as sell as holding the gun smoother. And try to move your work to make all the welds in the horizontal or flat position rather than vertical up or overhead. Here's some pointers I found that helped me http://www.millerwelds.com/pdf/mig_handbook.pdf
Western
Super Member
It could be several things, from old or poor wire. Looks by the pics that possibly the wire may be hanging up, check the feed wheel make sure its clean and snug. Hopefully there is no damage to the feed line. IE crimps or hang up's. You may try turning the amps up a tad and turn your puddles slower into each other. Also pay attention to the duty cycle, 20% is extremely light use, time wise. look in your manual on "duty cycle" for a good explanation. basically, out of an hour you can run her good for 20% of the time. (Thats a general statement)
DJ54
Elite Member
- Joined
- Jan 20, 2009
- Messages
- 4,678
- Location
- Carroll, Ohio
- Tractor
- IH Farmall 656 gas/ IH 240 Utility/ 2, Super C Farmalls/ 2, Farmall A's/ Farmall BN/McCormick-Deering OS-6/McCormick-Deering O-4/ '36 Farmall F-12/ 480 Case hoe. '65 Ford 2000 3 cyl., 4 spd. w/3 spd Aux. Trans
What Does 泥uty Cycle
Mean?
Duty cycle is the amount of time
during a 10-minute period that
a welder can operate at a given
amperage without overheating. For
thicker metals or bigger jobs, choose a
welder with a higher duty cycle
I copied and pasted this from Millers website. If you've got the amperage turned up to weld heavier material, then 2 minutes is it...
Mean?
Duty cycle is the amount of time
during a 10-minute period that
a welder can operate at a given
amperage without overheating. For
thicker metals or bigger jobs, choose a
welder with a higher duty cycle
I copied and pasted this from Millers website. If you've got the amperage turned up to weld heavier material, then 2 minutes is it...
Egon
Epic Contributor
I'll go along with that. There is also a lot of metal there as a heat sink.
RPW
Veteran Member
- Joined
- Aug 12, 2009
- Messages
- 1,105
Also remember with MIG your mantra needs to be "clean, clean, clean". Any bit of dirt will affect how how well your welds will be. Also if you are trying to weld in the wind or have a fan blowing accross your work that will also affect the quality of the job.
Good luck
Good luck
Steve C
Platinum Member
The welds on the left side of picture #1 look very cold with little penetration. The weld seems to be gobbed up on top of the metal. The angle is opened up to greater than 90 degrees, this creates a lot of surface area to suck the heat out of the weld material. You might want to try a figure 8 weave when trying to apply wide welds in these large opened angle welds, it works well for me with stick welding to help keep the heat in the weld zone. It also seems that even your good looking welds have a slightly negative profile, you may need to move a little slower to permit more material to be deposited, that may also help in keeping the weld hot improving the penetration a little.
I have had good results using a stick welder for thicker materials 3/16 to 1/2" thick tube steel and such. It is hard to go wrong with 1/8" or 3/16" 6011 or 7014. It is a lot easier getting deep penetration from a stick welder, after all the flame front of a 3/16" diameter rod is .187" in diameter vrs a .030" or .035" diameter for a wire welder. This gives you a flame front that has about 5 times as much heat in it. Penetration is much easier to achieve, at least that has been my experience. The welds take a little longer to clean up, but if the rod has been kept dry I have seen the slag break loose and curl up in 6" and 8" long strips when welding horizontal with 7014 requiring only a touch with a wire brush to remove the slag leaving a very pretty weld that looks like it has been polished.
If you get a chance try your hand at using a stick welder for base metals that are 3/16" and thicker.
Last edited:
Bill_C
Gold Member
Oh, I didn't really notice at first that this is a 110 volt unit...try not to use an extension cord, that machine needs all the voltage from the wall it can get. Clean the steel to shiny clean as others have said. And for gas, run 100% CO2 for max penetration (rather than C25 or C10) in thicker stuff.
Keep your stickout to 3/8 or 1/2 inch, and keep the arc at the leading edge of the puddle. When the arc gets trapped in the puddle, it's losing energy through the puddle rather than penetrating the steel.
The 20% duty cycle--conventionally that means you can weld continuously at full rated current for 2 minutes out of 10. Which is fine for most home/hobby work, you'll weld a little then take a look at it, fiddle around, then weld some more. Duty cycle increases if current is decreased, say if you're welding a lot of sheet metal work.
Keep your stickout to 3/8 or 1/2 inch, and keep the arc at the leading edge of the puddle. When the arc gets trapped in the puddle, it's losing energy through the puddle rather than penetrating the steel.
The 20% duty cycle--conventionally that means you can weld continuously at full rated current for 2 minutes out of 10. Which is fine for most home/hobby work, you'll weld a little then take a look at it, fiddle around, then weld some more. Duty cycle increases if current is decreased, say if you're welding a lot of sheet metal work.
Scooby074
Super Member
I have the same welder.
As others have said it has to be clean
How thick is this metal? Are you beveling your metal before welding? Your likely maxing out your machine. While one weld looks fine, it may not be strong (especially if you wernt beveling your joints) this is one problem with smaller migs.
Besides the joint prep, i think the you were "jerky" with your hand. Maybe you were in a little more uncomfortable position. The joint looks cold and not centred. You can see how the bead is proud of the surface and not "melted" in.
I noticed that on the lower edge of the bad weld, where the factory bevel is, your weld looks better, this leads me to thinking joint prep (and undersized welder) is a major cause.
You can also improve penetration with a small machine by using the backhand technique.
I attached a pic to help you diagnose your welding issues. It may give you an idea whats wrong (amperage too low, travel too fast)
As others have said it has to be clean
How thick is this metal? Are you beveling your metal before welding? Your likely maxing out your machine. While one weld looks fine, it may not be strong (especially if you wernt beveling your joints) this is one problem with smaller migs.
Besides the joint prep, i think the you were "jerky" with your hand. Maybe you were in a little more uncomfortable position. The joint looks cold and not centred. You can see how the bead is proud of the surface and not "melted" in.
I noticed that on the lower edge of the bad weld, where the factory bevel is, your weld looks better, this leads me to thinking joint prep (and undersized welder) is a major cause.
You can also improve penetration with a small machine by using the backhand technique.
I attached a pic to help you diagnose your welding issues. It may give you an idea whats wrong (amperage too low, travel too fast)
Attachments
tnhomestead
Bronze Member
Maybe ask at weldingweb.com, some really helpful folks, and some ideas to mod your welder to improve it.
Scooby074
Super Member
Do you happen to have a link to the mod thread? I searched weldingweb and didnt find much. Thanks
Are you plugged into a 20 amp circuit? Had similar problems with my Clarke 110v mig. It would weld great for a little bit and then would not weld worth a darn. I was running on a 15 amp circuit and that is just not enough. Switched to a 20 amp and it made me look like a pro (well not really a pro but A LOT better than fighting it at 15 amps).
Hope that helps.
Hope that helps.
Ken Cunningham
Gold Member
- Joined
- Feb 11, 2008
- Messages
- 264
I found this to be true also. I dont remember if someone else allready said this or not, but turning up the current and slowing the wire speed will produce a better looking weld. If you run a bead and it looks like its just sitting on top of the material then it probably is. Get some scrap and run some test beads to tear apart and then you will see difference in strength by judging the looks of the weld.
DaveOmak
Platinum Member
Hiltz, Good morning.
Looks like the amperage and wire speed are ok for a thinner material. Doesn't appear to be proper penetration of the parent metal.
Try turning up the amps and increasing the wire feed until you hear a smooth buzz of the wire burning. A smooth puddle should appear that flows smoothly.
Second. May seem dumb but can you see the puddle flow? I need to use reading glasses from the drug store to weld. Try some that lets you see really well at 18" or so. They really improved my welding when I could see the molten metal flowing. So far it looks like your doin pretty good.
Looks like the amperage and wire speed are ok for a thinner material. Doesn't appear to be proper penetration of the parent metal.
Try turning up the amps and increasing the wire feed until you hear a smooth buzz of the wire burning. A smooth puddle should appear that flows smoothly.
Second. May seem dumb but can you see the puddle flow? I need to use reading glasses from the drug store to weld. Try some that lets you see really well at 18" or so. They really improved my welding when I could see the molten metal flowing. So far it looks like your doin pretty good.
DaveOmak
Platinum Member
Hiltz. Argon CO2 10%. I use .030 wire. Tilt the gun about 15 deg foreward in the direction of travel. Weave the bead from one piece to the other. the width of the weave should be no more than 1/4". The weave will help heat thicker material by keeping the weld in a smaller area for a longer time. I'm not familiar with your welder, I set mine at 18-19 constant voltage electrode positive. When welding thicker material, 1/4" and thicker,preheat the metal to 300-500 degrees with a weed burner. Preheated material will help a smaller welder with penetration and reduce the possibility of cracking. Preclean the metal with acetone etc. and grind or sand to remove all scale from the rolling process and also rust. ACETONE IS EXTREMELY FLAMMABLE. Hope I helped. Good luck, Dave
Wineslob
Member
See the above response^^^^^^^^^^^^^^^^
plus notice that the vertical down weld in the first pic (right side) is pretty acceptable. I going to guess you backhanded the weld. Thats probably the ticket with a small machine, concentrate the heat.
The "bad" welds are, as has been pointed out, "cold". Try to prep the weld areas a bit more, and try to use a backstepping/backhanding technique with the figure 8 or a "C" motion, but keep that puddle molten and moving. Don't overdo the motion of the gun.
Just remember, you are trying to make that machine do a tad more than it can.
plus notice that the vertical down weld in the first pic (right side) is pretty acceptable. I going to guess you backhanded the weld. Thats probably the ticket with a small machine, concentrate the heat.
The "bad" welds are, as has been pointed out, "cold". Try to prep the weld areas a bit more, and try to use a backstepping/backhanding technique with the figure 8 or a "C" motion, but keep that puddle molten and moving. Don't overdo the motion of the gun.
Just remember, you are trying to make that machine do a tad more than it can.
