new toy questions

tomslik · August 12, 2004, 07:46:33 AM

soo, i bought a snap-on mig/tig outfit and i'm playing with the tig.
all i've got on hand is some 75/25 argon mix when they want 100% argon and i'm having trouble keeping an arc.
is the gas mix my problem or something else?

this tig is the scratch and sniff type(no hi freq).
just trying it on steel...

PCFree · August 12, 2004, 09:15:34 AM

Yep, it's the gas. CO2 is used in mig for penetration. the argon is the shield. Sometimes straight CO2 is used with MIG for heavy steel but the spatter caused makes it impractical for sheet metal work. With TIG, you are looking for a straight shielding action since you are using a constant arc rather than the short-circut method of MIG. The CO2 is causing the arc "Blow-out"

tomslik · August 12, 2004, 08:45:33 PM

Quote from: "PCFree"Yep, it's the gas. CO2 is used in mig for penetration. the argon is the shield. Sometimes straight CO2 is used with MIG for heavy steel but the spatter caused makes it impractical for sheet metal work. With TIG, you are looking for a straight shielding action since you are using a constant arc rather than the short-circut method of MIG. The CO2 is causing the arc "Blow-out"

once upon a time back in the dark ages, i worked for an irrigation pipe mfgr and on the .064 aluminum we used an argon/helium mix(.050 was straight argon).

that's kinda why i thought i'd try the 75/25.
oh well, learned somethin' new

thanks for the help!

unklian · August 12, 2004, 10:46:12 PM

Argon and Helium are both inert gases.
The big difference is Argon is heavier than air,Helium is lighter.
You could use either one,or a combination of the two for Tig.

Any mix that includes Carbon Dioxide won't work for Tig,
that extra little bit of Oxygen creates too many problems.

tomslik · August 13, 2004, 06:56:15 AM

Quote from: "unklian"Argon and Helium are both inert gases.
The big difference is Argon is heavier than air,Helium is lighter.
You could use either one,or a combination of the two for Tig.

Any mix that includes Carbon Dioxide won't work for Tig,
that extra little bit of Oxygen creates too many problems.

how come it works for mig?

PCFree · August 13, 2004, 08:50:08 AM

MIG welding is a different welding process. Where TIG is an "electric flame" that uses a constant arc, MIG uses a "short circut" method where the wire extends to the metal, makes contact, and the contact heats and melts the wire where it then falls into the weld, breaks the circut and the process starts over. That is what makes the "bacon frying" sound. It is the contact and the subsiquent melting of the wire that makes the weld. The oxygen in the CO2 helps ignite the metal (yes, just like in oxy-acc. cutting, the steel actually burns!) to help with the penetration. There is another MIG technique called "spray transfer" where the wire speed is slowed down to create a constant arc and the wire melts before it reaches the work. The polarity of the arc is what draws the molten metal to the work. This technique is used with aluminum MIG welding and produces a "hissing" sound.

tomslik · August 14, 2004, 09:38:30 AM

Quote from: "PCFree"MIG welding is a different welding process. Where TIG is an "electric flame" that uses a constant arc, MIG uses a "short circut" method where the wire extends to the metal, makes contact, and the contact heats and melts the wire where it then falls into the weld, breaks the circut and the process starts over. That is what makes the "bacon frying" sound. It is the contact and the subsiquent melting of the wire that makes the weld. The oxygen in the CO2 helps ignite the metal (yes, just like in oxy-acc. cutting, the steel actually burns!) to help with the penetration. There is another MIG technique called "spray transfer" where the wire speed is slowed down to create a constant arc and the wire melts before it reaches the work. The polarity of the arc is what draws the molten metal to the work. This technique is used with aluminum MIG welding and produces a "hissing" sound.

so,let me ask ya 1 more question.
is there a problem with using straight argon with a mig?

jaybee · August 14, 2004, 12:36:24 PM

Quote from: "PCFree"There is another MIG technique called "spray transfer" where the wire speed is slowed down to create a constant arc and the wire melts before it reaches the work. The polarity of the arc is what draws the molten metal to the work. This technique is used with aluminum MIG welding and produces a "hissing" sound.

Is it possible to get decent results with aluminum using a MIG?

C9 · August 14, 2004, 07:54:59 PM

Yes, there are problems using straight Argon with MIG.

I tried both the 75/25 mix and straight Argon with both MIG and TIG in an effort to only have one gas bottle and regulator.
Didn't work.

The 75/25 with TIG produced a somewhat smoky arc flame and a dirty and sometimes porous weld.
With straight Argon - welding mild steel in all cases - it made very nice welds.

Straight Argon with MIG made a difficult to control arc that didn't seem to penetrate or weld good at all.
Looked sorta like a booger collection after I was done.

tomslik · August 15, 2004, 09:23:40 AM

Quote from: "C9"Yes, there are problems using straight Argon with MIG.

I tried both the 75/25 mix and straight Argon with both MIG and TIG in an effort to only have one gas bottle and regulator.
Didn't work.

The 75/25 with TIG produced a somewhat smoky arc flame and a dirty and sometimes porous weld.
With straight Argon - welding mild steel in all cases - it made very nice welds.

Straight Argon with MIG made a difficult to control arc that didn't seem to penetrate or weld good at all.
Looked sorta like a booger collection after I was done.

thanks, looks like i gotta have another bottle:(

Sean · August 15, 2004, 09:50:35 AM

Quote from: "C9"Yes, there are problems using straight Argon with MIG.

Depend's on what you are doing. MIG on Aluminum is done with straight Argon.

tomslik · August 15, 2004, 11:18:09 AM

Quote from: "Sean"
Quote from: "C9"Yes, there are problems using straight Argon with MIG.

Depend's on what you are doing. MIG on Aluminum is done with straight Argon.

hmmmm, keep goin' guys, i'm learnin' somethin'

PCFree · August 15, 2004, 11:26:21 AM

MIG has one "soft" point to be made aware of. Because the wire is softer than steel, it can bird-nest easily. If using the full length gun with the wire drive in the welder, bird-nest cleanup can eat up wire & time. The best way to do Aluminum with MIG is a spool-gun. This is a weld gun that has the wire drive and a small spool of wire at the head. If you do bird-nest, it is a quick reset. The added bonus is that the wire speed control is right at your finger tips as you weld for easy adjustment. Remember, also, this is different than steel's "Short-Circut" method. The wire speed gets turned back to a hiss sound. Oh, and don't forget that stainless-steel brush. Everything has to be clean, clean, clean! And care for that brush as if you used it in your mouth! Don't use it for any other purpose other than aluminum welding!