Thinking about Stick welding

[Groo]

I know MIG (somewhat) and have a good MIG set-up, but it has its limitations (mobility and running outdoors). I have been playing around with getting a Stick machine.

I hear DC is easier to work with and some things like hard surfacing need DC, so I guess I want a DC capable machine.

I started thinking the Lincoln Electric AC/DC 225/125 would be the one to get. While researching I found the Home Depot has it for $100 less than anyone else. I know HomeDepot often does cheapened up "specials" made in the HD China plants, but this has the same part number; K1297. Any idea why it would be so much cheaper than elsewhere? http://www.homedepot.com/Tools-Hard...splay?catalogId=10053&langId=-1&storeId=10051

and then while at the HD site, I saw this little number; 200-Amp IGBT Inverter ARC Welder-STWD-S-200i at The Home Depot
I sure it is "Chinese junk", but for just over half the price of the super cheap Lincoln AC/DC tombstone that has a 100% duty cycle were the Lincoln is at its max in DC and has only 20%. They also both have the same 3 year warranty.

I understand the technology is quite different, but the little inverter one sure looks like the way to go. Any downside to an inverter welder? Would I ever miss the AC?

Then the other question is; should I just save up for an engine driven unit since I'd probably only be using this when and were using the big MIG isn't a viable option anyways. Maybe even just stick a welding alternator on the Kubota?

I'd like something like the Miller Dynasty 200DX for more versatility and TIG capabilities, but that pricepoint just isn't in the cards.

 

[Shield Arc]

If you're are going to do very much Tig work on heavy aluminum forget the Dynasty 200. My 300 is pretty much maxed out on 3/8-inch thick aluminum.
I'm all for engine drives, got 1 or 5 of them my self.
Look at Everlast, and Longevity before you make your decision.
No you won't miss AC on one of these little SMAW machines. With out a high frequency add on you will not be able to Tig weld aluminum anyway, but you can Tig weld steel ,and stainless steel, with a simple Tig rig.

 

[Groo]

Why does TIG need so many amps on aluminum? just the thermal conductivity of the metal?

I did start thinking Longevity and Everlast after making the post, but I am leaning more toward saving my pennies for an engine driven machine.

 

[Shield Arc]

Yup aluminum is one big heat sink.

My buddy has a Lincoln 305-G, very nice machine.

Or you could get a good generator, and a DC Inverter welding machine.

Ranger 305 G Engine Driven Welder (Kohler)

 

[dstig1]

TIG doesn't need a lot of amps on alum... ANY WELDING needs a lot of amps on alum. Alum is one of the best conductors of heat, so you need to pump lots of heat into it to get a puddle going, and maintain it.

 

[Shield Arc]

That's very true! Look at this Mig weld on 10-GA aluminum.

 

[Groo]

I think TIG is more base metal temp sensitive than other forms of welding though, just by the way it works.

 

[dstig1]

Geez CEP, yer just bragging now

Welding properly is about melting the base metal and the filler. If you can't get and maintain a puddle, you are not getting a good weld. That takes heat, and alum conducts it so well that you need to pump a lot of heat in quickly to get the puddle going and stable before the base metal sucks it all away.

 

[Groo]

I get that, but still; TIG is more like soldering in that the whole area hast to get hot first. MIG and stick heats the pinpoint location where the filler is introduced. Maybe in the real world there isn't much difference, but it strikes me that there would be some noticeable differences in heat required between the 2 types of operations, especially when "battling" a good thermal conductor. Maybe I am just not understanding the TIG process. I certainly wouldn't put that notion outside the realm of possibilities.

 

[Gary Fowler]

TIG is nothing like soldering. It pinpoints the heat much more so than stick but it still has to get the basemetal hot enought to melt in that pinpoint area. With aluminum the heat input is sucked away to adjoining molecules as fast as the TIG rig puts it into it so you have to really pump it in at first to get the puddle going. If you look at Shield Arc Mig, you will notice that when he first started welding(right side of photo) the toes or edges of the fillet are rather cold lapped. It didnt start flowing well till about the middle of the weld. Most times it is necessary to preheat with a torch to stop that from happening or have a thumb control amperage adjustment that you can crank it up to start then turn down after it get hot otherwise you end up with cold lap at first and blowout hole later from too much amps.