welding wire thickness....

motoxscott

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I'm hoping some people that have been welding for quite a while can answer this for me.......Jerry..........Nestor.................

What material thickness would you recommend for these thickness MIG welding wires? I've been using .035 for the most part on stuff .090 - 3/16" mild steel and I'm using a 75%-25% CO2-ARGON gas and it seems to do all right. I'm curious what everyone else is using

.025 (example .090")
.030 (example .120")
.035 (example 3/16")

I just ordered a Lincoln PowerMig 255 so that's what I'll be using.

Thanks for any info......

-Scott
 

cleartoy

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I use .035" with 75/25 co2\ar on .120", 3/16 and 1/4". It does fine.

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EQuin

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According to my welding instructor, all the MIG welding machines (a variety of Miller and Lincoln brands) at Mountain View Community College use .035 wire and 100% CO2 gas in class (probably because it was cheaper that way, though). Throughout the semester I used them all on varying thicknesses (1/8" to 1/4") of mild steel with no problems. If I remember correctly, our instructor recommended a mix of 75 Ar-25 CO2 gas for mild steel .

If it's available to you, check out the book "Welding: Principles and Applications," (4th ed.) by Larry Jeffus and Dewayne Roy (one of our instructors). Lots of excellent info on most every aspect of welding. Table 10-3 of the book recommends a slightly lower voltage for a 75 Ar-25 CO2 mix than with a 100 C02 gas. It also suggests a higher wire speed with .035 wire than with .045 wire.

Hope this helps. Take care,



Ed Q.
 

EQuin

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Wait a minute - after re-reading your post, are you saying you're using a mixture of 75% CO2 and 25% Argon? Or the other way around (75% Argon and 25% CO2)? If it's the former, I don't see that mixture in the table. The table only gives amperage (wire speed) and voltage paramaters for 100% CO2, 75% Ar-25% CO2, 98% Ar-2% O2, and 100% Ar. I don't know the parameters for the former mixture if that's what you're using.

Take care,


Ed Q.
 

AZmiik

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Has to be a typo. On mild steel the 75/25 gives you a nice bead apperance, where as 100% CO2 gives you better penatration. .035 and .045 are good all around wire sizes. I have been doing 3/8 vee butt and tee joints in all positons with the .035 with both gas mixes both work very well. If you want to get ahead get the wire manufacturers guide lines for the application. It will tel yo min and max volts and amps for wire size and what positions it works best with. These are avaliable on line or at you welding supplier.

Mike
 

motoxscott

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For the most part I've been using .035, would their be any advantages or disadvantages to using .030 instead on mild steel .090 - 3/16" thicknesses ?

I can buy a roll and try it, I'm just curious what everyone else is using. For the most part the majority of my welding is on tubing.

I'm looking for real-world recommendations, rather than what I can find in a book. .......Not trying to be harsh.
 

SpareChangeRacng

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The smaller wires (.023, .025) burn hotter and will give you better penetration on the thicker stuff (.120 +) when used on smaller 110v machines. If you have a larger machine like a 220v I go w/ .030 or .035. Steve
 

cleartoy

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The TIG at our shop uses Argon only.

Cutting torch uses oxy and acetelyne(sp?).

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EQuin

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From what I learned in my welding class, the gases in MIG are shielding gases which help protect the molten weld pool from oxidation and contamination. The gases can affect the arc, the rate of metal transfer (from electrode to base metal), weld heat and penetration.

Some gases, like argon for instance, are inert, which means they can cause an erratic arc on ferrous metals (mild steel), but work fine on non-ferrous metals (aluminum and titanium). So if you want to use an inert gas on a ferrous metal, you should add a reactive gas, like oxygen or carbon dioxide, to help stabilize the arc and improve the metal transfer.

As for gases, these are the ones I can remember, although I'm sure the more experienced welders on this forum may know of some more:

1. Argon
2. Helium
3. Nitrogen
4. CO2
5. ???

These are the gas mixtures I remember, but I'm sure there are other mixtures I'm leaving out:

1. 75% Ar - 25% CO2
2. Ar and He (don't remember the percentage)
3. Ar and Nitrogen (don't remember the percentage)
4. Ar and 1-5% O2 (might be other percentages?)
5. Ar and 5% O2 and 15% CO2 (I'm pretty sure this is the percentage our instructor wrote on the chalk board)
6. CO2 and O2 (don't remember the percentage)
7. ?????

The different gases and gas mixtures are used to weld different metals, like aluminum, copper, stainless steel, plain carbon steel, low alloy steels, different alloy steels (chromoly, for instance?), etc.

I learned alot of this info from class and from reading our course book ("Welding: Principles and Applications," 4th ed., by Larry Jeffus and Dewayne Roy - an excellent source referencing American Welding Society guidelines and recommendations). But so far, the only practice I've had with a MIG is on mild steel (plate, tube, pipe, bars, scrap, etc.) using straight CO2 gas and .035 wire.

Hope this helps. Take care,


Ed Q.
 

crashesalot2003

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does anyone know if 100% nitrogen will work on mild steel, i was just wondering because my tank ran out and i have a full n2 tank from paintballing and don't have money to fill the other tank right now. do you think it would work in the meantime.

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EQuin

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I don't think 100% nitrogen is used with mild steel. If I remember correctly, nitrogen can be mixed with argon for non-ferrous metals, like aluminum and copper. I've heard of an argon and CO2 mix with mild steel, but I've never heard of a nitrogen and CO2 mix. Then again, I'm still new at this, so I don't know. I believe, though, that when using inert gases, like argon and helium, on ferrous metals (mild steel), you need a reactive gas like carbon dioxide or oxygen to stabilize the arc. You also need a deoxidezed wire to eliminate or reduce porosity in the molten weld pool from using a reactive gas (like CO2) on mild steel.

Hope this helps. Take care,

Ed Q.

Ed Q.
 

Timmah

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Ya know, since the air we breathe is about 78% Nitrogen, 21% Oxegen, and about 1% other crap (unless you live in the 909), I'm gonna have to go with the popular opinion that Nitrogen may not be good for a ferrous weld. If the Nitrogen was the shiznet then we probably wouldn't need a shielding gas at all.
Just a hypothesis, but it makes sense to me!

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