Looking for mig welding advise! I'm still pretty green

I have little experience with mig welding but I think I would like to attempt to seal up my new exhaust with some welds since the clamps are not really sealing. I have a Hobart Handler 140 it is a 115v 25 to 140 amp mig welder I bought it awhile back so I cn finally start learning and have only had half asses success. It came with a spool of .30 flux cored wire and I am having a heck of a time laying a good weld. From what the wire spool states is says I dont need shielding gas since it is flux cored but I am having my doubts. I seem to always get spattered and spotty welds no matter the voltages or wire speed combo. Do I need shielding gas irreguardless of flux cored or wire thickness? Also what wire thickness I should be looking to use on the exhaust pipe and what shielding gas? Are there smaller tanks of gas like a half height or quarter height? where do I buy the recommended gas at? I would love to learn how to get better but since I dont even know where to buy the gas at I think I should be asking for help lol.

 

Flux core welding leaves horrible looking welds. Lots of craters and spatter. Get some gas and solid wire and you'll impress yourself the first time out.

 

If your machine is set up to run the shielding gas use it and non flux core wire. Any welding supply will have the tanks. you can buy or rent them. Theres a youtube page called welding tips and tricks. Look it up and watch all you can. I wanted to pick up some skills last yr. Went to the local tech school and paid for a semester in the welding class. Was well worth the money.

 

I use 75% argon, 25% carbon dioxide with my mig welder. On exhaust, I would use .025 wire. There are also different types of wire. Talk to your welding supply company and practice, practice, practice! I agree with Briz, it wouldn't hurt to take some classes.

 

Used my Mig to make new teeth on the flex plate of the F250. During the trip this week it started to grind and not catch when the bendix was pushed out. After we got home I put it up in the air, pulled the inspection plate and starter to find 2 ground down places of 4-6 teeth. Filled the area with steel and used a cut off wheel on the grinder to shape new teeth. Works great now.

 

Remember, when you have a hammer, everything looks like a nail. When you have a welder, everything looks like whatever the heck your sick twisted mind can dream it to be!!

But seriously, ditch the flux core wire and get some solid/gas. I've used the handler 140's and they're decent machines. But you're handicapping your results with flux. Not that you cant get ok welds with flux, but your going to have a tougher time as it's just an inferior method. The only time Id use it was if I was outside in a windy enviroment where shielding gas would struggle. As was mentioned, get some 75/25, watch some YouTube instructional videos, and get a bunch of scrap to practice on. That alone will get you a long way.

 

I agree with reading up on Mig welding as there are 4 modes of transfer when Mig welding that can be changed by setup, changing what are called essential variables. I know this sounds like a bunch of BS but read and practice it will begin to make some sense and your welds will get better. Good Luck Jim

 

Thanks guys! I had hunch the flux core wasn't a cure all and more like a "tool" for certain scenarios. I feel that I'll get much better results with the gas/solid wire combo now and it will be a case of perfecting the voltage/wire speed.

 

yes the flux core wire requires more voltage. really cant screw up much with those little machines as far as the settings. I have the Miller equivalent of your Hobart machine and it runs great for small jobs and thin metals. set the voltage about half to 3/4 with .030 wire and then just tweak your wire speed. If its popping you have too much wire speed, and if its surging or melting before it lays a bead then not enough. You can use 75/25 or straight argon for shielding gas. if your outside the wind will blow your gas away and leave you with holes all thru your weld so maybe crank up the outlet pressure a bit. you can also run downhill with solid wire which makes it much easier, especially on thin metals.

 

Flux core is good for big oil pipe sewage pipe and out side in the wind 60 feet up on grain elevator pipes. In the hands of certified welder, one tap with the pointed hammer all the flux falls off.
Plus it cools a might slower so it will not crack.

 

The gas creates a bubble to keep impurities out of the weld while welding, so turn off your ceiling fan or shop fan, you don't want the breeze with the gas being used.
then practice, practice, practice...

 

here is a tutorial, lots of good information, it is a long tutorial and has ended ubruptly. but its worth a look!

https://www.ford-trucks.com/forums/1162712-new-tutorial-welding-101-theory-and-practice.html

 

The best advice I got about welding is this...”90% of making a good weld is metal prep”...especially with mig welding...my welds got a lot better when spent more time prepping the metal surfaces to be welded together

 

When I learned to weld it was with a whip and pause motion... back and forth 1/2" and a pause just long enough to say you did and always PUSH the MIG gun. You need the gas ahead of the wire. If the base metal is cold or wet (damp) warm it up with a propane torch for a few minutes. ws

 

Practice makes perfect. I think you are pushing the puddle if you will.

 

I bought a Hobart 140 when Northern Tool was selling them on clearance them a few years ago. I learned right away to stay away from flux core wire. Very messy. If there is a Tractor Supply near you they sell small tanks of gas. The initial purchase includes the price of the tank. After that you just pay for refills (or swap it out).

 

My only caution with this (and it may just be my area) is the welding supply places near me won't fill a personally owned tank. They'll only fill their tanks that you lease. That said, it's actually not a bad deal, because you never really pay for the tank (directly anyway, you know they not "free" but you don't have an upfront charge like purchasing one). Basically you sign the lease agreement, pay for the gas, and when it's empty you take it back, exchange for a full one and just pay for the gas again. It's really a pretty good deal. I lease an 80cf tank with c25 gas. Haven't had to swap it in a few years (though I'm getting low), but it's no problem to show up and swap for a full one whenever.

 

Keep in mind (a beginner mistake) that you have to remember to switch the electrode polarity with flux core vs gas shielding. If you haven't done this you will have a hell of a time trying to weld with flux core.

 

Good heads up! Years ago when I first started out, I made this very mistake.

 

You are not alone bud. LOL!