Which mig welder, gas or flux? Options

[Thack]

I did a search but couldn't find the thread I once saw. Anyone have bad things to say about the flux wire mig welders? (IMG:style_emoticons/default/welder.gif)
I know gas is better,. I have a tig at work but the car can't come thru the shop door. (IMG:style_emoticons/default/headbang.gif)

[r_towle]

flux core welder leaves spatter and requires clean up.
Gas mig leaves alot ALOT less spatter.
Tig is very clean.

I have used flux core for a long time for two important reasons.
Its cheap to purchase.
I can get flux core wire 7 days a week. I cant get gas 7 days a week.
One more....

It works outside in wind, that is a plug for household and farm stuff.

Rich

[Joe Bob]

I use the Miller with shield gas (argon). Makes an idjut like me look gud....

[Thack]

So should I pass on the cheapie $100 welders that use the flux? Wait until I can afford a hel/argon gas mig?

[Wes V]

So should I pass on the cheapie $100 welders that use the flux? Wait until I can afford a hel/argon gas mig?

You should pass on a cheap welder -- end of statement!

Think of a welder as long term investment. Get one from a major manufacturer that has their name on it (not something that "is built by XXXX) so that you know you will be able to get parts latter. Even quality stuff wears out.

Wes

[jd74914]

I would suggest getting a nice Lincoln or Miller and using the flux core wire for it in the short term.

Then you can always save up and get a gas bottle later. Most or the more expensive welders come with the regulator so the gas bottle is plug-and-play.

All of the welding I've done at home has been flux core (meaning everything on my 914) and it came out pretty nicely. At school I use MIG and more frequently TIG which is really clean, but I still feel that the flux core is ok for the work I do at home. (IMG:style_emoticons/default/smile.gif)

[Joe Owensby]

I bought a Lincoln flux core welder to use initially. I later bought the adapters to be able touse gas with it. The gas is much cleaner, and works better on thin metal such as sheet metal, etc. I don't remember the price, but the first main unit was 2 - 300 dollars, and the gas adapter system was less than 100. The flux core works very good for thick stuff, but I highly recommend the gas for doing body work. JoeO

[orange914]

So should I pass on the cheapie $100 welders that use the flux? Wait until I can afford a hel/argon gas mig?

depends on what you want and how much you use it. a nice argon miller is great but you may be keeping yourself away from getting one if you cant justifiey the cost for the use or 220v hookup. we got a cheap harber freight $125 (115v) flux for around the house that does just fine for what light duty stuff we do. DEFINATELY pay the additional return policy ($20). they even have a 115v that is tank ready. the only weird thing to get used to is the feed trigger DOESN'T control the current, it's always on. you have to control it by moving the tip away (IMG:style_emoticons/default/welder.gif)

[pjf]

I use a Miller 135 that I got through an Ebay merchant for $569. One thing that sold me on the Miller is that it has all metal wire drive parts and overall is very well built. I haven't used a MIG that adjusts in increments so they may be fine but I know that being able to inifinitely adjust the juice and wire speed comes in handy especially when doing thin metal. I'd say if you have a lot of welding to do and can afford it, its like any tool, the good ones are a pleasure to use and you won't regret paying the extra. That being said I'm all for getting what you can afford too. Most of 914 welding is out of sight so if the flux core welder will work just not as pretty, not a problem.

[HeloMech]

I bought a mig from harbor freight about 2 years ago. Back then, it was like $179. It had the inlet on the back to add gas. Figuring I would eventually burn it out and move to a lincoln or miller, I opted to go to an actual welding shop where I picked up quality regulators and my own gas bottle which is an argon/CO2 mix.

I've heard you get better penetration with the flux, no gas... however, if I put this little welder on #2 and HI, it will blow through any steel I've used for building go-karts, etc.

One thing to remember, at least on the HF mig welder, you need to reverse the polarity inside the side cover if you switch from flux core to gas.

Oh, the regulator and filled gas bottle were about $220 and the harbor freight welder is still working fine. (IMG:style_emoticons/default/piratenanner.gif)

[Jeff Hail]

I wrote this a number of years ago for an article. Probably more than most need to know. Hope it helps.

Most welders used for automotive sheet metal and/ or collision repair are 220 volt. Does 110/115 volt Mig Welders have the power to do the job? They can. For plug welds a 110/115 home type welder can be done safely and successfully. For continuous, butt, and filet welds confirm the machines capacity and duty cycle.

Something’s to consider:
Consider the capacity ratings of amperage and duty cycle. Pure Co2 versus C02/ Argon will lower the amperage requirement but;

Pure Co2 is not recommended for High Strength Steel.

Duty cycle:
Is how many minutes the welder can safely operate at given amperage level continuously over 10 minutes. Duty cycle rating will change, depending on how much amperage is used.

For example a Mig welder with a 200 amperage capacity and 60% duty cycle might be able to:

Weld continuously for 10 minutes (100% duty cycle) if operating at 160 amps.

Weld only 4 out of 10 minutes (40% duty cycle) if operating at 190 amps.

A 115 volt Mig welder rated at 90-100 amps will weld 24-18 gauge uncoated steel with 0.23 (.6mm wire) using argon/Co2


The thickness of the metal being welded determines the amperage needed. Generally one amp of welding current is needed every .001 (.025mm) of metal thickness.

A MINIMUM of 90 amps is needed for automotive uncoated sheet metal. Remember most of the time two pieces of sheet metal are being welded which doubles the thickness.

If you are welding 0.23 (.6mm wire) can be used on any thickness and is generally accepted in automotive sheet metal repairs.

If you are welding with 0.30 (.8mm wire) can be used on 22 gauge and heavier thickness (gauge)

0.35 (.9mm wire) can be used on 18 gauge and heavier thickness

Shielding Gas:
The correct shielding gas depends on the metal being welded. Some general guidelines are:

Mild steels and High Strength Steels use 75% Argon/25%Co2

Pure Co2 reduces the needed amperage and provides deep weld penetration. The disadvantages are: penetrates too deeply on thin gauge metal. Burns out manganese and silicon in the electrode which lowers the strength of the weld. Makes an uneven arc and lots of splatter. (ear wax sizzle)

Electrode Wire and AWS codes:
Ratings of AWS ER70S-6 and AWS ER70S-7 are best suited for thin gauge mild steel and High Strength Steel sheet metal used in automotive use.

Flux Core:
Stay away from it when welding thin sheet metal. It creates an aggressive weld that is less than ideal in appearance. It is really suited well for zinc coated steel. Flux core burns too hot for thin metal. Heat is difficult to control on metal lighter than 18 gauges.

Heat (Voltage)
The heat setting, or voltage, determines the length of the arc.
More voltage, the longer the arc. The longer the arc, the wider and flatter the weld since the wire melts of in larger drops. Too long of an arc for the wire diameter used results in splattering. Too short of an arc for the wire used rsults in a pulsing sound.

Wire Speed:
Setting the wire speed when MIG welding also affects the amount of amperage applied to the weld. Changing wire speed mainly affects weld bead: height, penetration, width.
To get a steady arc with a steady sound and correct penetration, both the heat (voltage) and wire speed (amperage) must be matched to each other. First set the heat, then the wire speed.

Travel Speed:
Travel speed is how fast the person moves the gun across the joint. The slower the speed the deeper the weld penetration, wider the weld, more bead height. If penetration or width is not right changing the travel speed needs to be altered. Changing voltage and wire speed are first considerations. If height of the weld bead isn’t right then adjust travel speed.


Before you weld do your homework. For cosmetics home 110/115 Mig welders are usually fine. For structural concerns such as rockers, longs, floors, aprons, rails, strut towers I would go with a 220 volt unit. With experience you will be able to "hear" a good weld.


The Test:
Take 4 pieces of 18-22 gauge mild uncoated steel sheets.

Drill or punch a bunch of 8mm holes in two of them.

Test #1
Lay one piece with holes in them on top of another without holes.
Use a 110 Mig welder with 0.23 wire and proceed to plug weld the holes.

Test #2
Now take the second piece with holes punched in them and lay on top of the other piece without the holes. Use a 220 Mig welder and same size wire (0.23) and proceed to plug weld those holes.

Look at the back side of the unpunched sheet metal. You will immediately notice the difference between the 110 test and the 220. It will be visibly obvious which is the better weld.

Penetration of the top piece with the holes on both tests will be comparable because the weld is being directed at the edge which easily melts. The bottom piece (solid) is harder to penetrate because the weld is being directed at the surface which is harder to melt.

There are three things that are vital to look for:
(Visible penetration) is the height of the exposed surface of the weld on the backside.

(Burn mark) is the heat indication on the backside.

(Burn through) is penetrating too much into the lower base metal or burn a hole through the backside.


The dynamic differences between 110 and 220 Mig welders are important. The easiest way I can explain this is electrical pressure (amperage) and speed (volts).


The same principal in Mig welding exists. You want the most oomph without burning a hole in the shortest amount of time.
The shorter duration of 220 versus 110 Migs means less surrounding heat distortion due to heat up time which is between 20 and 200 times per second. (short circuit transfer) ideally the rate is 180 times per second for thin gauge sheet metal. This is where the weld produces that steady sound similar to bacon frying. (Remember: Learn to hear the weld)

Another easy example would be like starting a car with a brand new fully charged battery versus an old partially drained one. The volts may be the same and both may spin the starter motor but amps are what turn the crankshaft.

When looking at a Mig weld profile the 110 test plug will appear somewhat like a triangle. The plug at the top piece of metal will be thicker and tapered down as it penetrates into the lower piece of sheet metal. The 220 test will be more uniform in profile and cylinder in shape effectively equal thought out both pieces of sheet metal and stronger.

When the wire pre-heats (first contact and trigger pull) directly affects penetration deep enough into the weld. Faster heat up time 220 versus 110 also reduces the amount of (air) asorbed into the weld itself regardless of shielding gas creating tighter molecules resulting in a stronger plug with less crystallizing and porosity. 220 Mig welders will puddle faster and directs heat quicker to the weld area allowing uniform and deeper penetration versus the 110.

In the automotive repair industry Mig welding plugs are a safe effective alternative to the costly Resistance Spot Welding (Squeeze Type) equipment used by OEM manufacturers.
Over 90% of factory welds are RSW’s. Extremely high current and pressure are used.
Factory RSW’s use at least 2.5 Kilovolt Amps at 50% duty cycle. Most Collision repair shops that use RSW equipment use a peak 7,500 amps measured at the electrodes. This type of equipment is available in both 220 and 440 volt versions to replicate the OEM spot welds. 220 volt Mig welders are the accepted replacement for these mega amp/volt powerhouse’s in the automotive repair industry.

Common sense dictates the closest alternative should be used is a 220 volt Mig welder with a “minimum” of 90 amps.

Hopefully this can educate those getting into welding and provide some insight. Learn as much as possible and apply your skills through practice. When Mig welding on automotive sheet metal safety is job one. Integrity of the weld is vital. The above examples were primarily focused on plug welds but the same theory and principles apply to also to butt and fillets welds.

[sww914]

I have a nice 110 mig with gas. I'd never used a flux core welder until recently. It is messier and it spatters like an arc welder, but I'd much rather have a cheap flux than nothing.

[seanery]

gas is king.
Miller 135 is a good starter rig.

[rfuerst911sc]

Hobart is a sister division of Miller and is another good welder. I have the Hobart 135 which is a 110v full mig with regulator,tank etc. and it does a nice job for a hobby welder. I've welded on fender flares,various chassis stiffening kits and it did fine on all.

[jmill]

I have a Hobart myself. The only difference between my hobart and a miller is the infinite heat ( amp ) adjustment. The Hobart is stepped and the miller is infinite. As long as you have infinite adjustment on either the feed or the heat you can adjust it correctly. My hobart has infinite feed adjustment.

[Dr Evil]

I welded for the first time last week and used a Hobart gas MIG 115v set up. It was nice and easy once you get used to it. I need to practice more as my welds looked a bit ugly (very).

[type47]

I welded for the first time last week and used a Hobart gas MIG 115v set up. It was nice and easy once you get used to it. I need to practice more as my welds looked a bit ugly (very).

wow, that patient must have needed a heck of an operation. heart transplant? brain tumor?

[Dr Evil]

(IMG:style_emoticons/default/tongue.gif) Cancer repair on the bus. (Excision of cancerous material with autologous tissue transplant over excision site)