Which mig welder do you prefer? I need to buy one and this is where I was reading some reviews Best MIG Welders under 500: Detailed Review (Spring 2022) but I have zero knowledge of welders. Any help would be appreciated!
Welder Recommendations
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What can you afford and what are you going to use it for?
I like stick myself because the best welder for a job is usually the one you are familiar and practiced with. You need to understand about the process of welding metal first before you start investing in any welding technology. Best weld process ultimately depends on your application and the nature of the materials you are working with. Stick is useless on sheet thin material, great on big stuff, I use it lots because all the equipment and rod came to me free. My welder is Alternating Current so I have to be careful with positioning the parts to be welded, so that gravity works, impossible to weld upside down unless you are in zero G environment. if it was Direct Current it would weld a little easier on awkward angles. MIG can be done with or without shielding gas but you need to understand the importance of shielding gas because all of the welding technologies ultimately depend on shielding gas. The shielding gas is what keeps out oxygen and stops things from getting too hot and burning up material and or spattering.
I like stick myself because the best welder for a job is usually the one you are familiar and practiced with. You need to understand about the process of welding metal first before you start investing in any welding technology. Best weld process ultimately depends on your application and the nature of the materials you are working with. Stick is useless on sheet thin material, great on big stuff, I use it lots because all the equipment and rod came to me free. My welder is Alternating Current so I have to be careful with positioning the parts to be welded, so that gravity works, impossible to weld upside down unless you are in zero G environment. if it was Direct Current it would weld a little easier on awkward angles. MIG can be done with or without shielding gas but you need to understand the importance of shielding gas because all of the welding technologies ultimately depend on shielding gas. The shielding gas is what keeps out oxygen and stops things from getting too hot and burning up material and or spattering.
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@fredrik21 I moved your post and Trials reply here - you might get more replies.
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I mentioned this in another thread but it probably belongs here too: When you are welding steel tube from the outside and want to achieve a good clean weld on the inside of the tube, they fill the tube with argon shielding gas before welding and that protects weld material that would otherwise spatter and blow through the weld seam on the inside of the tube.
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Yup, heat from the outside will suck up any impurities from the inside and cause porosity in the weld (bubbles that get caught as the weld pool cools) not only is it ugly, it makes for a very weak weld that can break easily
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I only knew about filling tubes with argon because that's how they weld the tubes in a nuclear power plant.
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Point to ponder - exhaust companies put miles of weld beads on exhaust pipes every day, and never fill the tube before welding. Numerous alloys, often mixed materials in the same weld, they never backfill the tube or converter body or whatever is being welded. NOT filling the tube is standard practice in an industry that does this stuff every day and then puts a warranty on the finished parts. A decent weld that doesn't break is just as good as a perfect weld that doesn't break.
When I say "never", I mean I worked in the industry for 30 years and never saw a tube being backfilled on a production line. A lot of years ago I had a prototype system made out of titanum (rejected material from the nuclear industry) and the welder may have backfilled that, I've forgotten, but it is the only time in 30 years I remember this even being talked about. So ok, if you're welding together a titanium system for your Virago then maybe you will need to take precautions that aren't typical for an exhaust system. Let's assume you aren't using titanium in this discussion.
For the last couple years a big part of my job was breaking exhaust components. Welds were a major part of that. I tested thousands of welded joints to failure, none of them failed due to impurites being sucked in from the backside of the weld. If a welded joint failed too soon, the welds were dissected, polished, studied under a microscope. Impurities in the weld weren't the issue. The fix was never to start backfilling the pipe.
If your exhaust weld breaks, it won't be because you didn't backfill the tube. If you're sticking together two used pipes with a $150 harbor freight welder in your backyard, backfilling the tube isn't your big worry.
I won't argue "best practice" if you want to obtain the best possible weld. But the thing is, you don't need the best possible weld for an exhaust pipe. It's not being used in a nuclear reactor and the pipe isn't titanium. It's going onto a Honda CBwhatever and the pipe is mild steel or maybe some form of stainless.
Clean the material. Make the joints fit decently. Get your settings right. Take a class/get instruction from someone who truly knows how to weld, and practice first. You'll be fine. Backfilling is not a fix for ANY of the previously mentioned details.
Would you expect body guys to flood the back of the panel with shielding gas when they put in a patch panel? No one fills the frame tubes before welding them. Do people fill the swingarm before welding a brace onto it?
When I say "never", I mean I worked in the industry for 30 years and never saw a tube being backfilled on a production line. A lot of years ago I had a prototype system made out of titanum (rejected material from the nuclear industry) and the welder may have backfilled that, I've forgotten, but it is the only time in 30 years I remember this even being talked about. So ok, if you're welding together a titanium system for your Virago then maybe you will need to take precautions that aren't typical for an exhaust system. Let's assume you aren't using titanium in this discussion.
For the last couple years a big part of my job was breaking exhaust components. Welds were a major part of that. I tested thousands of welded joints to failure, none of them failed due to impurites being sucked in from the backside of the weld. If a welded joint failed too soon, the welds were dissected, polished, studied under a microscope. Impurities in the weld weren't the issue. The fix was never to start backfilling the pipe.
If your exhaust weld breaks, it won't be because you didn't backfill the tube. If you're sticking together two used pipes with a $150 harbor freight welder in your backyard, backfilling the tube isn't your big worry.
I won't argue "best practice" if you want to obtain the best possible weld. But the thing is, you don't need the best possible weld for an exhaust pipe. It's not being used in a nuclear reactor and the pipe isn't titanium. It's going onto a Honda CBwhatever and the pipe is mild steel or maybe some form of stainless.
Clean the material. Make the joints fit decently. Get your settings right. Take a class/get instruction from someone who truly knows how to weld, and practice first. You'll be fine. Backfilling is not a fix for ANY of the previously mentioned details.
Would you expect body guys to flood the back of the panel with shielding gas when they put in a patch panel? No one fills the frame tubes before welding them. Do people fill the swingarm before welding a brace onto it?
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If it was exhaust tubing, chances are they were Tig welding it, don't have enough experience in that welding process to give feedback. I know mig welders have a tendency to suck oxygen in like a sponge. It doesn't happen all the time but Jesus when it does it is not a pretty sight. You can get away with a little bit of porosity in a weld and it will still have it's tensile strength, but too much and it will snap with a little bit of force.
And if it were me, I'd never put my faith in a HF welder, but that's only my opinion
And if it were me, I'd never put my faith in a HF welder, but that's only my opinion
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Exhaust plants buy wire for Mig welding in spools so large they need to be moved with fork lifts. Tig welding is rare in a production setting.
This is an every day real world this is how it's done sort of thing. No back filling. Mig welds done as fast as possible. With a robot if possible. Flip the switch and let 'er rip... after a lot of design and set up. I'm not talking about guys building headers for one off vehicles. I'm talking about 700,000 F150s per year, literally millions of welds each and every year. Mutilply that by every other mass produced gas powered vehicle you see out there. OEMs don't weld up systems for a generic passenger car with a tig welder.
Don't get me wrong, if I had the resources I'd Tig the exhaust on a one off build too. But by no means is it NEEDED, or common outside of hand built systems. Point being, if you are using a MIG welder, there's no need to backfill the pipes. OEMs have proven time and time again it is not needed to get a perfectly useable weld. And by perfectly useable I mean one that will pass durability and leak standards no one here will ever have to deal with on their home built bike.
On converters that have very strict leak limits, repairs on Mig welds are common enough they plan for them. But it's never an entire weld that's porous, it's a section with some flaw that gets touched up. If an entire weld is porous enough it's leaking everywhere they shut down the line and change welder settings. If you are getting welds so porous the joint isn't strong, backfilling the tube isn't going to solve your issue.
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Ahh damn my fault, when you said exhaust my mind jumped straight to stainless steel.
I was running 550 pound barrels of .045 wire myself back when I built trailer chassis. Had to change one about every 3 weeks. My main problem with porosity in my welds came from welding the tops of my risers to the upperdecks. After I welded the riser tube to the ibeam all the gases and fumes forced itself out through the top, so when I was putting weld down at the top my shit was getting horrible contamination. This wasn't all the time, but it was to be expected.
I was building some rocket stoves a couple months ago and kept getting bubbles in my welds. Had the settings right on spec, gas was at 25 CFM and metal was clean, but I couldn't for the life of me figure out why my welds were coming out like that, hence why I figured it must be drawing air in from under the seams
I was running 550 pound barrels of .045 wire myself back when I built trailer chassis. Had to change one about every 3 weeks. My main problem with porosity in my welds came from welding the tops of my risers to the upperdecks. After I welded the riser tube to the ibeam all the gases and fumes forced itself out through the top, so when I was putting weld down at the top my shit was getting horrible contamination. This wasn't all the time, but it was to be expected.
I was building some rocket stoves a couple months ago and kept getting bubbles in my welds. Had the settings right on spec, gas was at 25 CFM and metal was clean, but I couldn't for the life of me figure out why my welds were coming out like that, hence why I figured it must be drawing air in from under the seams
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CO2 works as a shielding gas too and I imagine that would be a cheaper alternative.
They were welding stainless steel, the boilers in nuclear power plants are made with thick stainless steel.
... have you seen some of the projects on this site lately, they are filling gaps with a minute welder, they are not gearing up for the production of 14 miles of thin wall exhaust pipe and that wire must be flux core which means it is still using shielding gas, just in a very controlled environment. Wouldn't surprise me if they could just heat it a press forge a weld seam on pipe either. Duty cycle on a small portable welder does not compare with production welding machines either, with a small welder you can't weld continuously all day long.
They were welding stainless steel, the boilers in nuclear power plants are made with thick stainless steel.
... have you seen some of the projects on this site lately, they are filling gaps with a minute welder, they are not gearing up for the production of 14 miles of thin wall exhaust pipe and that wire must be flux core which means it is still using shielding gas, just in a very controlled environment. Wouldn't surprise me if they could just heat it a press forge a weld seam on pipe either. Duty cycle on a small portable welder does not compare with production welding machines either, with a small welder you can't weld continuously all day long.
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"If a welded joint failed too soon, the welds were dissected, polished, studied under a microscope. Impurities in the weld weren't the issue." <- I on-site serviced those big expensive microscopes they used to do exactly that and big companies that produce expensive products do it with everything, it's called destructive testing.
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