right now i have a small Campbell housefield MIG welder and a large miller generator/stick welder. I taught myself how to use the MIG and had a family friend teach me and my brother how to use the stick, but i was wondering how difficult it is to learn how to TIG weld.
1)Should i get the air cooled or the liquid cooled TIG if i get the attachment for the miller.
2)Should i also just spring for the MIG gun for the miller since it is a better system.
3)Do i need gas shielding in order to weld with stainless wire or aluminum wire in the MIG.

Depends on thickness of the metal to be welded. The more amperage you put to the tip of the tig the hotter it will get. Non liquid cooled tigs rely on the shielding gas to get rid of the heat so there is a limit to how long and how much amperage the non liquid cooled can stand with out self destructing. You will neeed to have a gas shield for both tig and mig welding. Aluminum usually uses argon shielding. No Co2 blends, it will look like #$%^.
stainless can be welded with argon, but there are two and three blend gases that are more ideally suited to this alloy. I would spring for the mig if you have the money, as they are a little more versatile for repair work. They have a longer reach,if you get a 1lb spool gun, and are better suited to working in place, rather than benchwork, as the Tig is best suited for. Both have their merits. You will need about 180 amps minimum to weld aluminum, as the aluminum conducts heat very well and it takes a little more juice to keep the weld area hot. Tig can be done with stick welding machines to weld steel and stainless, but you will require AC to tig weld aluminum, and preferably a high frequency option to stabilize the arc.

the miller has more than enough power it a 250 or 225 bobcat which puts out 250 or 225 amps(i'm at work and i can't remember which model my brother and i have) and it does allow for both ac and dc welding. the only thing is I don't rememper it having a gas hookup, unless that comes with the attachments.

Is tig hard to learn or is it about as difficult as mig or stick

Its not hard to learn, just hard to do very well.

For one thing you are using both hands, one to hold your flame on the material and the other to feed a filler rod as necessary. Balancing the addition of new filler material and moving the puddle where I needed it to go consistently was pretty hard for me. Some people don't have any issues at all.

thanx

there's an old saying I heard from a welding instructor....
it takes 5 minutes to learn how to weld, and the rest of your life to learn how to weld properly. TIG ain't that hard, but there's a little more coordination involved. You have to manipulate the puddle, operate a foot or hand control for amperage and manually add filler wire, which also acts to penetrate the parent metal as well as cool the weld puddle. Kinda like chewing gum, walking, and juggling with a bucket on your head!
ps The Miller 30 A 1 lb spool gun is all we use specifically for MIG welding aluminum to 3/4" thick. It's a pretty durable setup.

well it sounds like a mix between stick and mig welding. You're right about the learning and the right way. The family friend that showed us how to weld had been welding for thrity years or so, and he has told us some stories about prodution welding for big companies that he's worked for. unfortuantly i will probably never get as much experience as he has since i do office work all day for an ins. company.

if you go to the miller welder site there are some guys there who are real pros at this stuff..

On your Miller welder it depends on which model you have as far as running a tig setup is concerned..

The new Miller line has computer contol which make tigging much easier..Look at the dynasty line for this..If you have not used the GTAW process before you may be better off to get one of the kits from Miller as they come with all the correct pieces to work properly together..mixing and matching is for the pros..

just my thoughts on this one..

__________________
I would rather make it work than make it popular..And if it does not work it will not be popular..

yeah i know that you really need to know what your doing to mix and match but my brother and i just spent 3 grand on this miller welder and I don't want to drop another grand on a seperate machine especially since we're running out of floor space. Our welder is only a couple of months old and allows us to do a really nice job on the welds we know how to do, i just wanted to see about making the welder a little more universal.

I just went through all this a few months ago and what we wound up with is what you have with what is called a suitcase for running GMAW..(MIG) This way we can do stick and MIG welds..The rig that was ordered cost somewhere in the 5-6000 category so we could do all that was required of it..

Take a hard look at the materials you are working with when looking at welding equipment..This is for general consumption for anyone reading this..

If you are working with 4130 in chassis work you will need to tig..working with very thin sheet metal is another tig app..

For general purpose the stick/MIG setup will be all that you will need..That is all I use around here and I do quite a bit of what one would call repair work..

Hope this helps you to make your decisions..

__________________
I would rather make it work than make it popular..And if it does not work it will not be popular..

Were's the talk about tig welding basics? Not that my 2 cents are basic. One question regarding TIG was air cooled or liquid cooled TIG machine. I prefer using liquid over air. Better for large production welding. Tig welding becomes more technical when dealing with BioTechnology companies that want it to BPE standards dont want pinholes, cracks, crevaces, under cut and over cut within +/- .008", part shrinkage can't be more than +/-.030" over all, tacking large manifold and valve assemblies that have to have correct angles, degrees, measurements all within .030", most parts jig welded on turn table, welds are pre purged with argon using silicon stoppers with stainless tubes in them. That's just some of the stuff I went through. Everything is inspected by a third party.

Here are some of my welding tips for stainless steel:

* 1amp per .001" metal(approx.)
* Tungsten 1/16" .025 - .085" metal thickness
* weld lens 11 or 12
* Use thin deer skin gloves (better control and easy on hands)
* comfortable chair
* 1 second delay for every .035" (preheat)
* Arc gap .045 Torch angle 70 degrees
* Tungsten stick out approx. 1/4"
* Use largest ceramic lens cup possible
* 30 sec. pre-purge and 30 post-purge general rule
* Regulator Backpurge 25-30 Arc purge 10
* Use some thing to prop arm in relaxing position (table vise/tube)
* Overlap after 4th level continue 1 second per .035"
* Downlslope (slowly reduce amperage to create tail at end of weld
* Post purge with argon 25-30 seconds (keep weld clean)
* The weld around a part is broken down into 4 levels
* Determine weld time and amp level with this formula

1) Tube outer diameter x pie = Circumference
____________ x 3.141 = _____________

2) Inches Per Minute divided by Circumference = RPM
____________ divided by ______________=____

3) 60secs divided by RPM = Time for 360 degrees
______ divided by ___ = _______________

Total Weld Time
(Time for 360degrees+Rotational Delay+Overlap= Total Weld Time
________ + _______ + _______ = _______

(Total Weld Time + Number of Levels = Time per Level)
___________ + __________ = __________

I guess I could go on forever. I've taught a few people that are as good as me now.

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Nice technical offering 4x4,
Will's 53 was originally asking about equipment selection. The average dude does not have to worry about passing NDT, but at least it gives them the idea of how stringent quality control can be for the professional welder. One of the most important points you made was about being comfortable. It is pretty hard to have a steady hand if you are straining to maintain position. You should post some more info on the various types of electrode preparation required for different types of parent metals. Normally we use a pointed thoriated tungsten for steel and stainless, and a zirconiated tungsten with a balled end for aluminum. 4x4 also made a good point about purging the area inside or behind the area to be welded. It can dramatically improve the weld quality. It also exposes one of tig's vulnerabilities is the need to have near perfect control of the environment for the best results, ie no wind, moisture,dirt, or even fingerprints!

This may sound pretty basic but from some of the above comments TIG is similar to oxy/acetelyne welding with 2 hands and a puddle to move. I did oxy for years but never have done TIG so how difficult is the transition??

If you can do well with oxy/acetelyne you'll pick tig up pretty quick. Once you get the machine setup you'll like it better than gas welding.

I wanted to point out different varibles to give an idea of what can be involved with stainless steel. Heat levels are also important because you can change the composition of the metal so that the metal is a lesser quality than the original material started with. Obviously when welding the part it becomes hotter so you need to reduce amps. Controlling heat and speed can greatly reduce weld shrinkage. For example in my field we already know how much a part will shrink if properly welded. The VP of the company use to weld and he would shrink a part .120" and I'd weld the same part and it would only shrink .025". Patience and fine tuning are the key to good welds.