Hello NCAV8R, you may want to take a serious look at some of the inverter type welders if you are looking for some serious power in a smaller package. My experience with these as opposed to the syncrowaves and other conventional type machines is that they actually weld to the thicknesses and claims that are stated. The Miller Dynasty 200 is an excellent machine with a number of great features, the Thermal Arc 185 GTSW is also another excellent choice with a host of extra features, it sounds as if the Lincoln equivalent of these two machines has a fairly serious flaw, this issue was discussed in a couple of threads on the Forum recently, so I might be a bit apprehensive to go with the Lincoln machine. You already have made the first correct move in your hunt by saying that you will try the machine out before making a choice and spending the money. In most cases if you have a dealer in your area who believes in good service they will allow you to do the test drive so to speak. You will likely do better getting rid of your Precision Tig 185 by selling it yourself and not trading it in. Good luck and have fun. Regards, aevald

ndav8r

To get the most out of what you currently have.
Try these things;

Water cooled torch.. You really ought to have one to be successful with the type of projects you describe.

Full length 3/32 or larger electrode with a blunt point and a more radical taper rather than a slim one. Cerium or Zirconium. Thorium will spit when it's overheated, if your thorium tip begins to distort you must assume that tungsten has already transferred across the arc into your work. The full length tungsten acts as a heat sink for itself and will take a good 10% more amperage before overheating than a 1/2 tungsten in a short cap.

Perfect prep. mechanically remove oxide with 80 grit aluminum oxide disc or equivilant within 5 minutes of welding.

Pre heat is not as important as being patient and focusing on perfect technique. By this I mean that aluminum has a high rate of thermal conductivity and for 1/4 inch plate if you simply strike an arc and slowly increase your amperage the heat will soak just nicely. If you floor the pedal right at the start the electrode will overheat before your aluminum has absorbed enough heat to begin to melt. Taking your time here will really prove itself if you give it a try. In fact I bet you will report back that you had to ease off the heat at the end of the weld.

Set your balence control to about 7 or even higher if you are getting a suitable etch at the toes.

If your 1/4 inch plate is laying on your work table get if off. Clamp it up on small blocks with airflow underneath, Remove all heat sinks. This of course makes distortion more of a consern, but hey, we are working on the edge of your machine ouput and something must give.

Keep your torch angle 90 degrees to the work. Even a little push angle will rob you of valuable power by defocusing your arc to cause an oblong puddle.

Do a trial on your Lincoln power supply and see just exactly what the *actual* duty cycle is on the thing. Use maximum current on AC until the thing trips. Thats what the reset is for.... Not many tig welders actually weld even 4 out of 10 minutes arc-on time eh? I would be surprised if you actually had a four minute weld.

The Synchrowave 200 won't make you any happier. The Lincoln is a good machine and 15 more amps isn't going to change much in the long run.

Get a 75% helium/argon mix and some brown (zirconiated) tungsten.

You will be fine.

Good Luck

brad