Let's talk about MIG welding

   / Let's talk about MIG welding #1  

etpm

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MIG welding has come up again, what to buy, etc. I thought my experience as a long time welder might help the discussion. Since this is my experience your mileage may vary.
First of all, even though most folks call any type of wirefeed welding MIG welding, MIG welding really means using a solid wire and a shielding gas. And, in fact, MIG, which stands for Metal Inert Gas, is no longer used. GMAW is the acronym now. Gas Metal Arc Welding. I'm gonna use MIG if I mean solid wire and shielding gas. Welding with fluxcore wire is not MIG welding, though it is a type of wirefeed welding.
Even though I own two wirefeed machines, that are both capable of MIG welding, I find that I use my little 125 volt machine whenever possible. This is because it is light and easy to move as well as, and more importantly, being very easy to use. My 300 amp machine is a wonderful machine too but it only gets used when necessary. It is a large and heavy machine. It is smarter than me too.
My small MIG welder is a Lincoln SP125 Plus that I bought used about 20 years ago. The big machine is a Miller but I don't remember the model. I bought it used too. I wasn't that worried about buying used machines because they were both high quality machines. In any case I want to talk mostly about the small machine.
With the Lincoln I have welded steel and aluminum and brazed steel. That's correct, brazed. The thickest steel I have welded with the machine is 3/8" thick.
Welding with this machine is pretty easy and this is mostly because it is a high quality machine and the voltage and wire speed are infinitely adjustable. The controls can be set just the way I want for a particular situation and this is an immense help. For welding steel in the thickness ranges the machine is made for the guide on the inside of the door that covers the wire spool is plenty good. For welding outside of these parameters I rely on my years of experience welding with this machine to get the results I want and need.
For example, I use mostly .023 solid wire, not .030 wire. Using thinner wire has two advantages, it is good for thinner work when you are trying to put less heat into the work but also is better when welding thicker steel because you can get the thinner wire hotter than .030. The disadvantage is that it takes more passes that .030. So, depending on the job I will switch between the two.
When welding steel that is thicker that 1/4" or if the steel is cold then I pre-heat the work. I use a propane weed burner for this task most of the time. For steel 3/8" thick I get the work really hot. Not only is this necessary to get good and proper penetration it keeps me warm in the winter. Kinda sucks when welding thick stuff in the summer though.
I tend to use fluxcore wire for dirty work and work done outside because I don't need to worry as much about wind blowing away the shielding gas(ses) and because dirty metal welds better with fluxcore. I should point out that I NEVER make substandard welds on purpose. The welds I do must always be stronger than the parent metal, parent metal meaning the metal being welded. When I need to weld on dirty stuff it is usually because I am building up worn away surfaces like the bottom of the bucket on my backhoe. Places where I need thicker metal. Or when I am trying to repair a lawn mower deck that is badly rusted out and it is hard to get all the rust ground out and my neighbor is too cheap or can't afford to buy a new one and I'm doing the job for free. Dirty work is also work done when I have tried to grind out all the dirt and corrosion but think it is likely I will still find some small pockets of dirt and rust. The fluxcore wire is better able to handle these small pockets without making porous welds. Porous welds are brittle and break easy. Oil contamination is a major cause of weld porosity. This is because of the hydrogen that is in the oil. At welding temperatures the hydrogen will come out of the oil and dissolve into the molten steel. When the steel cools and hardens some of the hydrogen will come out of solution and cause porosity. Some will also stay dissolved. And the weld will become brittle for both reasons.
The 125 volt machines are not meant for aluminum but it can be done. Without a spool gun. Spool guns are mainly used for aluminum because it is difficult to push small diameter aluminum wire more than a few inches. So pushing small diameter aluminum wire through a 10 foot long whip is problematic. A 25 foot long whip even more so. That's why I have two Python whips for my big Miller, one for aluminum and one for steel. Both 25 feet long. Python whips pull the wire and work in concert with the rolls in the welder that push the wire. There is more than one brand of pull whips. Cobra whips are probably the most recognized. And the 125 volt machines really don't have the amperage to weld aluminum. But it can be done.
I have welded aluminum with my small Lincoln. I used the smallest diameter wire. I used 4043 alloy. It is harder to push without "birdnesting" than 5356 wire because it is softer. (Bridnesting happens when the wire cannot be pushed into the whip so it just piles up in a big tangle that resembles a bird nest.) But the welds I needed to do required 4043 alloy wire. I did this by using a teflon liner in the whip and keeping the whip as straight as possible. I adjusted the wire feed rolls to such a light pressure that the wire would stop feeding before it could birdnest. I pre-heated the work so that it was very hot, and welded away. I was welding 1/4" thick aluminum castings that needed to be built up due to casting defects. I later machined the areas built up with the welds. I found no porosity. I'm sure I could have welded 1/4" plate too with the same procedure. This would have made the plate soft and weaker if it was a 6000 series alloy but if I was welding a 5000 series alloy, like 5052, and using 5356 wire, the pre-heat would have made no difference to the strength of the parent metal.
I only attempted the aluminum welds with my small welder because at the time I didn't yet have my big Miller and I couldn't get my TIG torch into the bores that needed to be built up. But I did it and it worked well. And if I can do it then someone else could too.
I have TIG brazed a lot of steel parts. TIG brazing is usually done with silicon bronze wire. There are other wires available and I have used some of them. Like aluminum bronze. But MIG brazing is a thing too. I have done this using silicon bronze wire. I needed to braze some steel assemblies. Silicon bronze wire was specified. The job required many inches of brazing so I decided to try using my little Lincoln machine instead of the TIG machine. At one time, soon after I bought the Lincoln, I took a 1 day class on MIG welding from a very well respected instructor. The class was worth every penny. This class taught me how to MIG braze. So when a job came up a couple years after I took the class I was prepared to try MIG brazing an actual money paying job.
Since it had been some time since I had attempted MIG brazing I burned some wire on practice pieces to get proficient again. It didn't take long, it is easy. I used my teflon lined whip and had to pre-heat the work. But I got the job done, the beads looked good and were good.
So, my experience with a 125 volt machine has taught me that using a high quality machine can help a person make high quality welds. This is because of the way the machine can be adjusted and because the machine is so consistent. When adjusted a certain way the adjustment stays that way. It doesn't drift off of the adjustment. So when I adjusted the drive rolls to just barely push the aluminum wire the rolls kept that adjustment. And the voltage stays constant as the machine warms up. And the wire speed doesn't vary. My experience has also taught me that I can make good welds that are beyond the usual capabilities of the machine if certain things are done. Being able to make good welds within the envelope that the machine is made for helps when going outside of that envelope. Once a person learns what a good weld is and how to make them then using certain techniques that enable the machine to make good welds beyond its usual capability is possible without much extra effort.
Cheers,
Eric
 
   / Let's talk about MIG welding #2  
very interesting. I was over on another forum on welding and most everyone over there don't think much of the 125v welders. Nice to know that they really do work on smaller stuff. I've got a Hobart 190 and a buzz box, and the thickest steel I weld is 1/4" with most being in the 1/8" range.
 
   / Let's talk about MIG welding #3  
@etpm great post. I have questions for you. I have a Hobart 210MVP and want to put hooks on the bucket of my new tractor. My machine is set up with .024 solid core which I use for body work. I have been holding off welding the hooks until I could get all the stuff to run .035 solid core for the thickness of metal I thought I needed that.

So I thought i needed .035 to be able to get the settings hot enough to get good penetration? But you mention you use .023 and do more passes. Can you explain? And I apologize in advance, I am not an experienced welder. So if I am using the wrong terms then feel free to correct me.
 
   / Let's talk about MIG welding
  • Thread Starter
#4  
I don't know how thick the metal is that you are going to be welding. As I mentioned in my post I pre-heat work that is too thick to be welded cold with my little machine. If I had to weld thick painted stuff I would instead use my big Miller machine with .035 wire. So, since I don't know how thick your bucket is I can't really tell you if it needs pre-heating to be able to use .023 wire. I suggest you get a spool of .035 wire and a few .035 contact tips. This is because I suspect your bucket is pretty thick where you want to weld on the hook and I know the hook is pretty thick. And if you apply a torch to the bucket it is gonna damage the paint over a wider area than if you were to just weld it with .035 wire and be done with it.
If you do decide to go the pre-heat way make sure the steel is plenty hot. A good thing to do to get an idea about pre-heating work is to run a few passes on cold steel and then heat the steel some, run a few passes, then heat some more so that the steel is really hot and run a few more passes. The shape of the beads will change quite a bit. Another way to see the same effect is to start with some 3/16 or 1/4 plate and start running passes about 4 inches long. Make each pass right next to the previous pass. Don't change the machine settings. As the plate starts to heat up the your beads will start to flatten out.
It just occurred to me that using an oxy-acetylene might work for heating in your case. I usually use a weed burner because I want nice even heat over a large area. But to minimize damaging the paint you could grind the paint away as usual where the weld is gonna be and then a little extra. Then heat the area with a small rosebud or a large torch tip while heating the hook at the same time, then go ahead and weld. You will need to paint a larger area than if you just weld with .035 wire but you wouldn't need to wait.
Eric
 
   / Let's talk about MIG welding #5  
very interesting. I was over on another forum on welding and most everyone over there don't think much of the 125v welders. Nice to know that they really do work on smaller stuff. I've got a Hobart 190 and a buzz box, and the thickest steel I weld is 1/4" with most being in the 1/8" range.

Most "big time" welding sites are dominated by Stick Welders on big time welding projects.... The funny thing is my 120V Hobart Handler 140 hs handled all the welding projects I need to make for tractor implements and such to maintain my 10 acres.... My real problem is I tend to fabricate some thing a little on small/weak side, but with all the abuse they get the welds have not broken yet..... Again its all about the skills of the weldor and how he/she uses the equipment....
 
   / Let's talk about MIG welding
  • Thread Starter
#6  
very interesting. I was over on another forum on welding and most everyone over there don't think much of the 125v welders. Nice to know that they really do work on smaller stuff. I've got a Hobart 190 and a buzz box, and the thickest steel I weld is 1/4" with most being in the 1/8" range.
I can see their point. There are all sorts of crappy 120 volt welders for sale for cheap and it can be hard for an experienced welder to get welds they find acceptable using one of these machines. For an inexperienced person making good welds using a crappy machine can really be an exercise in frustration. But once someone gains enough skill to make welds with the proper penetration, no undercut, etc. then pushing their machine beyond its usual limits is possible. Any tool user does this. When I bought my first machine tool I was worried about it being too small. My dad and several other folks told me that no matter how big the machine is I will always want one bigger. That was so true. So do like I did and use your machines like so many, including myself, have done. Use your machine beyond the designed limits. Just make sure that when the job is done you did it well. Don't cheat on quality. You can push the limits of your skill and push the limits of your tools and get better doing so. But don't ever push the limits on quality, always make sure you have done at the least a good job.
Eric
 
   / Let's talk about MIG welding #8  
I agree with etpm and Wrangler X's comments. I have great respect for professional welders. They (literally) have forgotten more than I will ever know about different grades and types of metals and the associated wires and rods that should be used on them.

However, I am a self-taught "hobby welder". I learned to "weld" with a wire welder from watching a few tutorials and then mostly by "doing it" after I retired from the military. I only weld mild steel for my projects and I have learned to identify metals that have potentially harmful coatings on them that I should avoid OR only weld in highly ventilated areas. Attempting to weld the wrong metals with the wrong coatings or fluid residue on them can be lethal to you.

I too have a Hobart 125 Handler which is a 110 volt wire welder. It doesn't have the option for running Argon gas. When I wired my garage, I intentionally ran one 10 gauge wire to a dedicated 110 volt plug-in and then wired this one plug to a 30 amp 110 Volt switch inside my electrical box for the sole purpose of running my compressor and my 110 volt welder.

I have have often wondered how many people are trying to run their 110 volt wire welders off of non-dedicated plug-ins that are wired with 12 (or even 14) guage wire back to their electrical boxes. Then at the electrical box, they have a switch that is either 15 amp or maybe 20 amp. Your welder can't produce heat if it can't get all the "beans" it needs to make the heat. I run mine off of the dedicated plug-in I mentioned above which is wired to the 110 volt 30 amp switch in my electrical box. I figure it just allows my Handler 125 to get all the amps it requires to make good welds.

Within the last four years I have fabricated a full four-point canopy for my Kioti tractor (to protect my head from falling limbs in the forest), a carry basket for logs on the three point hitch. A log arch for hauling large logs. A carrier mounted onto the frame of my tractor canopy for carrying my chainsaw. A brush guard to protect the front grill of my tractor when in the woods. Quick removable forks, that bolt to my bucket, for moving brush and lifting logs. A safety loop over the top of my bucket to prevent the contents of the bucket from rolling back onto the hood of my tractor. I also cut down a larger box blade grader to size to fit my tractor and welded it back together. The box blade was built of 1/4" and 3/8" steel plate. It has held up very well to the abuse I give it. I've never broken one weld on it to date. I got excellent penetration on the welds that were easily visible from the reverse side of the plates. I've also welded 3/8" plate onto the bumper of a camper for carrying the spare tire. I have fabricated "rock rails" that attach to my Jeep's frame to protect the side of my Jeep when in the woods and also made some for another truck I used to own.

The point being to all of the above is, yes, a quality 110 volt wire welder can produce quality welds on metal up to 1/4" thick. Honestly, most projects for farmers and do-it-your-selfers will rarely require welding metal thicker than 1/4". Usually 3/8" steel or thinner. Those that regularly need to weld the thicker metals normally have a 220V stick or GMAW welders to do it. I totally agree with etpm that pre-heating the thicker 1/4" metal enhances the quality of the weld.

I keep both .035 and .030 fluxcore wire on hand... but I use the .030 wire most of the time. When I need "more" of a bead... I run second and third passes and even build the shoulder of the weld up as well. Flux wire is great for welding old steel. However, metal prep is still required for a good weld (wire brushing excess rust off, removing oils and contaminants as has been mentioned, beveling thicker metal to obtain more contact for the weld bead penetration, etc).

Your hand technique is important too. For instance, when welding a thinner metal to a thicker metal, you spend more time (putting more heat) on the thicker metal and drawing the bead into the thinner metal to keep from blowing through the thinner metal. We're talking micro seconds of differnece in the pass speed here.

For many projects I have built, I have used metal purchased from a local metal yard (junk yard). Old steel is good steel too and you can buy it at 1/3 the price of buying new steel. So if you can find the steel material you need for a project at a metal yard... why spend the extra money buying new? A 12 foot stick of 1 1/2" 1/4" tubing new cost me right at $120 dollars a few months ago. New metal costs can get salty quick.

At first I bought the small spools of welding wire at either Tractor Supply or Rural King ($20ish each). Then I finally decided to bite the bullet and buy the larger 10# spools of wire. I don't ever intend to go back to the smaller spools anymore unless I have to. Yes... the larger spools cost around $100 per spool BUT... you won't continually find yourself in the middle of a project and running out of wire! Until you get into projects you won't understand how frustrating and wasteful that is. Large wire spools? Totally worth it!

I bought my Hobart Handler 125 used about ten years ago. I bought a new Handler 140 over two years ago to replace my Handler 125, which I figured was getting long in the tooth from usage. The Hobart Handler 140 model has the ability to run Argon gas (GMAW). I loaded a 10# spool of .030 flux wire into the new Hobart Handler 140, tested it for function... but I haven't used it for a project yet. My little Handler 125 just keeps going and going!

Of all the skills I have gained since I retired... I think welding and fabricating has been one of the most useful and fulfilling skills I have gained. To be able to fabricate what you need, versus paying someone to fabricate or weld it for you is a priceless skill set. Just like being able to perform mechanical repairs and maintenance on your vehicles and equipment. It saves you so much money in the long run and is enjoyable to boot!
 

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   / Let's talk about MIG welding #9  
I have questions for you. I have a Hobart 210MVP and want to put hooks on the bucket of my new tractor. My machine is set up with .024 solid core which I use for body work. I have been holding off welding the hooks until I could get all the stuff to run .035 solid core for the thickness of metal I thought I needed that.
I would say you could use the .024 solid core if you did the prep work right. You can grind the hooks with a bevel on both sides where they attach and will be welded to the bucket, this way you will have better weld contact with the base metal. Also you could grove grind the bucket where you plan to weld the hooks and this would give you a better core weld. You would use multi-pass to build out the weld. The object is to form a weld from the core out for both the base metal and the hook you plan to weld on the bucket.

I would use .035 or .045 solid core and 95/5 argon/oxygen shield gas, this would give you a 93,000 psi weld and because it would take less prep work because of better penetration, my welders are setup for all three so it would be easy to choose.
 
   / Let's talk about MIG welding #10  
My Grandson is a Certified Welder. He can do better welds wrong handed than I can on my best attempts. Being a good Welder is an art. Some of us are artists, some of us are not... :)

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