Welcome Mike W.

Both Lincoln Electric and Miller make some decent machines...

I have'nt tried any of ESAB's new equipment though so I could'nt give you an opinion on those. I heard some good things about Thermal Arc's machines... Warranty coverage and the availability of factory trained warranty repair service from the supplier is an important factor to consider...

There are a bunch of factors to consider so, I'll try to mention a few, and if I miss some then, do'nt worry because, I'm sure someone else in the forum will fill in any gaps, and give their opinions, and advice also...

First thing you've got to consider is your input voltage/current supply...
What I mean is, if you've got 208 or 230 or 460 voltage, and whether it's single phase or three phase. Then you got to know what amount of current (Amps) you have available (enough to run the machine based on how much the machine "draws' or needs at maximum settings without being to close to the maximum current available otherwise you'll have to increase the amount that line input needs to run the machine with a comfortable margin so that the circuit breaker does'nt trip all the time.).
Inverter type power sources do this very well because, they require less current input to operate, (Three phase requires less current draw than single phase) so, ask your company whether or not they want to buy a single or three phase machine because, last time I checked they did'nt make amachine that you could switch "on the fly" from single to three phase (you have to open the machine and change the position of the jumper links just to change the line input voltage, and in order to switch from single to 3 phase, the machine must have 3 phase transformers and the appropriate circuitry in order to do so, if they're even available) nevertheless you need to start here...

With varying amounts of line voltage in different area's and regions of the country., Another important factor to consider is power factor correction. During different times of the day, line voltage can fluctuate depending how close you are to other industrial entities... If you have power factor correction, then your machine will be able to compensate for this, and operate without cutting out on you, due to voltage fluctuation occurring at various times of the day... (you need enough steady, consistent voltage in order to force or "push" the necessary amount of current through the the line connected to your machine so that it can run properly.)

Being able to use more than one input voltage amount is also important to consider because if your company wants to expand but, does'nt want to use let's say, use 460VAC, 3phase all over the place then, they could "Tap" off the 460 line and reduce the voltage to 230, using a variety of methods which I wo'nt go into detail, (another subject) so, this is important to discuss this with you company beforehand because, of the added costs of hiring an electrician to do this or if they have someone employed with them that can do this work legitimately which wolud require this person to be pulled off another job, etc...

Another thing you have to consider is how much maximum current output you need from the machine. It's considered good practice to go over the maximum amount that you will need... What I mean by this is, if your highest current requirement of let's say: 250 amps (output current) is needed then, it's a good idea to purchase a machine that can give you at least 300 to 350 amps output so that you do'nt push the machine to premature failure. Although most machines have decent thermal overload protection, it'll only protect the machine for so long because, "somethings gotta give eventually!!!"

You should also consider how much actual welding is going on when you're using a welding machine... Unless you're automating your application, and welding 24/7, a machine with a 60% duty cycle at it's near maximum current output rating should be sufficient for you
{the difference in the costs between some 60% and 100% duty cycle machines at the same near maximum (at actual maximum output, the duty cycle drops substantially) current output rating can be meaningful to say the least!}.

What is duty cycle? I'll simplify this explanation by saying that the amount percentage of let's say: at 60% duty cycle, this tells you that for every ten minutes of continuous welding at near maximum current (amps) output, the machine will give you six minutes of continuous current output before the thermal overload protection circuit shuts the machine's output (welding contactor) down, and the cooling fan comes on (running at lower voltage and current) to cool the components until the temperature reaches a safe operating level.
This could mean alot of delays and wear and tear on your welding machine if you do'nt make the correct decision regarding the amount of duty cycle you really need...

A word of caution: Please do'nt let some salespeople try to sell you a machine with extra's that you really do'nt need, like for example, if your not welding certain stainless steels or exotic alloys where controlling heat input is an issue or welding out of position with root openings on pipe joints , then you really do'nt need a machine with pulsing capabilties or a feature in which you can customize your output waveform (unless they throw it in for no extra charge, yeah right!).

Some machines come sold as packages ready to weld so, you also might want to take into consideration the quality of the components in the package, like the rating and type of the TIG (GTAW) torch, the type of flowmeter/regulator, etc. Having an extra one of each item does'nt hurt to have on hand in case one of your existing components breaks or does'nt work correctly. You want to match up as best as possible, the TIG torch or any other component with the parts you have already available for your existing torch (standardize your torch parts) in order to avoid confusion or lack of available parts for your torches.
Water cooling your torches can be done different ways but, if you do'nt choose the correct coolant, the torches wo'nt last as long as you would like, and neither will your water recirculator, nor will the solenoid valves required to turn on the flow of current...
Do'nt buy a machine that does'nt have built in solenoids that enable you to install a water-cooled torch should the need arise because, you'll regret it later... In other words do'nt buy a machine that does'nt enable you to expand your capabilities either!!!

Well, I'm sure that I did'nt cover everything but, theres a show on cable that I want to watch so, I'll stop here, and finish by reiterating that other well knowledgable people that frequent this forum will also add anything that I missed, and also help you in making the right decision regarding your purchase of a new machine... Gotta go!!!

Let us know what you decide before you buy though, so you can get some feedback about your decision, and make sure that you shop around to get the best overall price not only on the machine but, also on the shielding gas you're going to need also...

Respectfully,

SSBN727 Run Silent... RunDeep!!!

Considering your mandate to get what you need and add 50%-I would definitely look into the Lincoln Precision Tig 375. The ready to weld package with water cooler and torches is a decent buy. You should use a water cooled system on aluminum welding.

No, you don't need 375 amps for welding on 1/8 material, but the bigger machines seem to start better, run smoother, etc.

Before the Miller guys start jumping here, I want to state that I have been a Miller only tig guy for many years. (personally own both a Syncrowave and a Dynasty DX, and very particular about my aluminum welding arc). I have even been to their schools in Appleton.
At one point Miller had an edge-the Syncrowave 300 and the 351 were excellent machines on aluminum. The Syncrowave 350 and it's DX derivatives were not as good, in my humble opinion, if you were looking for the "best arc". They did weld very acceptably, though.

Lincoln has done a lot of positive work on their line in recent years. Much of it good, some not as good as we would like.

The Lincoln Squarewave 300 was decent as an introductory machine, but had some problems, none of them related to aluminum tig.
Their SW350 was an exceptional machine. The SW355 was ok, but not equal to the 350 on aluminum. The "auto balance" seemed to negate the very reason you bought an adjustable squarewave machine.
The Precision Tig 375 changed that. This is a very good machine, if you want to stay with a transformer based machine.

Enter the AC/DC inverters. They are good. They are extremely adjustable(sometimes almost too much so). They are very smooth. They weld aluminum much differently than traditional transformer machines (they use a pointed thoriated, ceriated or lanthanated tungsten on AC, for example)

When I got my Miller Dynasty inverter, I was going to dump my 15 yr old Syncrowave. I have found since then that some jobs are better done one machine or the other. Because of this, I have kept both. Relly gives me a range I did not have before.

There are other very high end machines available, but will not really give much more benefit for the greatly increased cost.

In all honesty, you really can't go wrong with a 350 class machine from Lincoln, Miller, or Thermal Arc (Hobart). They all make good, very usable machines.

If you are very fussy about your arc-look at the Lincoln Precision Tig-it is an extremely good machine!!

Try them all, if you can. Remember that service and experienced support from your local distributor is very important as well.

Good Luck

Brande

To reenforce the excellent advice you have gotten to this point. Here are just one or two things to consider.

If your work is mainly aluminum of varying thickness than a powersource with vairable frequency is really something you might want to have a look at. If you haven't used increased frequency on thin Aluminum (under 0.060) you should have your vendor set up a hands on demonstration (bring coke cans).Also, Dynasty has about 10% more adjustability in balence control than regular square wave powersources, this can be handy from time to tome. If your company has deep pockets, have the vendor set up a Miller Aerowave as well as the most powerful Dynasty to match up with the Lincolns.

My experience with Synchrowave 351's is considerable, too many internal "pot" adjustments to keep low end arc starting for my liking. The power is nice but if you don't need the extra push of the high end, the Synchrowave 250 is far more durable, I think due to is more simple circut board arrangement.

There is my 2 cents

PS. Which ever you decide to buy, a water cooled rig is essencial for top quality Aluminum work. Torch and Electrode life is extended manyfold. Make them put together package deals for your consideration.

Lawrence