[mschlee]

posted this over at hobart forum but thought ppl might have some view here. have a new 190 with spoolrunner 100 gun. put it together with 100% argon tank and 4043 .030" wire. trying to dial in the settings on some practice pieces of 1/8" 6063 (pretty sure as it is square tubing and corners are sharp not rounded) i'm having trouble and hoping someone can help.

started at the recommended 5/80 but it was burning through and welds were really flat. also had a lot of soot. played around and this is the trouble i'm having and questions:

1) power setting: seems like power at 4 gives a better weld (not too flat and not too high), temperature makes a huge difference as the start of the weld doesn't penetrate well and after about an inch it is better and at 3 inches or so it is way better. what is the best way to preheat? using map gas torch takes forever.

2) wire speed: this is my big challenge. i'm following the advice of longer stickout (3/4" or so). if i lower the speed down to get the nice hissing sound rather than the frying bacon sound i start burning up tips like crazy. if i watch the tip during the weld i see the wire pulsing shorter and longer rather than a constant length. i looked at the aluminum mig videos on wtt and it looks like the wire stays a constant length which may be why i keep burning tips?

3) soot: no matter how much or how little argon i use the weld is still full of soot. i was thinking i'm holding the tip too far but if i get too closer again i burn tips like crazy.

i assumed it would take a while to get it dialed in but the rate i'm going through tips can't be right.

any help is much appreciated

[AKweldshop]

First off,

Welcome to the forum!!

I had that same exact machine as you, and have done similar....

Is your metal clean??? Acetone??? And a stainless wire brush is a must!!

You can mess with your gas, but I would set your gas around 30-40cfh.

Preheat makes a lot of difference on thin stuff, lets you run with a colder setting, and not have a cold start.

I'm guessing you don't have an O/A set-up??

But,
Burning up tips, means too little wfs, so turn it up until it smooths out, and before it stubs....

Might get a picture or two up, might help....

Hope this helps,

~John

[mschlee]

thanks john. i think there may have been something wrong with the gun. swapped it for another and things are much better. i also went up to .035 and that seemed to help too. been playing with things and getting better. my flow seems really low though around 10-12 cfh. i'll play with it a bit more and post some pics.

no on the o/a. was thinking about getting one but seems like a lot to pay just to preheat - but not sure there is another option....

metal is new and really clean (i ss brush it just to make sure)

i'll post back shortly

[jimbob]

I run a lot of aluminum mig at work hopefully I can help. Your on the right on to preheat your parts to deal with the cold start issues. I use a miller 252 with a spool gun as well as a 350p with a aluma pro. Our spool guns run the best with a mix gas of 25% he 75% argon lots less soot than straight argon. Using a 10° or so push angle helps this also. Hope this helps you some

[mschlee]

thanks all. things are definitely looking better.

any ideas re:preheating? i dont really want to invest in an o/a setup (and i dont like the danger either). was thinking of using a propane roofing torch? you think that would work?

[Otto Nobedder]

Propane is economical. Even a weed-burner will be a fairly economical pre-heat,

Oxy/propane is almost as good as O/A for cutting steel, and way more economical than O/A for anything short of actual gas-welding.

Preheat is your friend on aluminum.

HOWEVER, wire-brush again after preheat... It leaves residue and oxides.

I've not used a helium mix on aluminum MIG, but I have NO doubt it's an advantage after using it on TIG.

The first symptom I saw was your description of the wire to spray moving back and forth at your tip, rather than remaining constant. The new gun helping supports this. An inconsistent feeder will cause this (even small variations in wire speed will mess with you... you have to run a tad too fast so the "slow" moments don't fry your tip). The increase to .035 would have diminished this problem "a bit" on the original gun.

Soot is a sad fact of life in MIG aluminum, but cleanliness helps. If your gun has room for it, a wire wiper between the spool and feeder is a good idea, to pick up any crap from the surface of the wire.

Just a few thoughts. I don't do enough MIG aluminum to consider my advice "solid".

Steve S