The Miller Syncrowave welder is considered an "old standby" by many amateur and professional car builders. They have been in continuous production for decades and have earned a solid reputation as a nearly bulletproof, easy-to-use TIG welding machine with a very stable arc. Miller recently released an updated version of the Syncrowave machine, the 210 TIG/Stick Welder, and the big news is that it is now powered by inverter technology. Miller has used inverter technology in other lines for some time, so it's not surprising to see the venerable Syncrowave come on board, too.

I first saw the Syncrowave 210 machine at the SEMA show in November 2013, and I was intrigued. It's designed for serious amateur welders and light-industrial applications (like street rod shops). I was able to try out this machine and put it through its paces thoroughly, and my report follows.

So what is "inverter technology," and does it really aid the welding process? All electric welding machines take the power that comes from the wall and change it into a form that is suited for welding. One of the chief changes is lowering the voltage, typically 115 V or 230 V as supplied by your power company, which makes high-amperage welding possible. This is done with a transformer. In older welders, the transformers had many windings of fat wire over a gigantic core, which often weighed hundreds of pounds. While this got the job done, the old-style transformers were not very power efficient, plus they were bulky and required a large cabinet to house them. Many of you have seen older TIG machines nearly the size of a refrigerator; this is the signature of the old-style transformer machines.

Inverter welders have transformers too, but what makes them unique is the solid-state circuitry used to boost the alternating current from the 60 cycles per second (hertz, or Hz) that comes from your wall outlet up to 1,000 Hz or more. The transformers in an inverter design operated much more efficiently at these stratospheric frequencies, so they can be made much smaller, and they don't have the same internal losses, which make them considerably more efficient. Once the voltage is dropped, more solid-state magic brings the hertz back down to more appropriate levels, and other beneficial tweaks can be added, such as shaping the AC waveform, adding pulse capabilities, changing the power to direct current (used for welding steel, stainless, and chrome-moly) and more. (I'll cover these in detail shortly.)

A rule of thumb for TIG welding is that you need one amp for every 1,000th inch of metal thickness that you're welding. For example, 1/4-inch plate requires about 250 amps of welding current, and with a traditional machine this might require a supply circuit with a 70-amp breaker. Not many home shops can provide this kind of power, and it can be quite expensive to add a new circuit. An inverter machine can weld 1/4-inch material while drawing only 30 amps, and a lot of houses already have this type of wiring in place to handle heavy appliances like clothes dryers.

Let's take a close look at the improvements that have been made to the Syncrowave 210. The compact size and reduced weight is probably the first thing you'll notice when comparing the new machine with its predecessors. It comes standard with wheels attached, and incorporates a sturdy platform for holding the argon cylinder. It's easy to move this machine anywhere it's needed, and I really like the low platform for the cylinder, easing loading, and unloading. There's lots of storage space inside the cabinet, accessible through a large, top-hinged door. This provides a place for storing the TIG torch, the foot pedal, the work clamp, and their cables. There is also a handy chart inside this cover, listing typical setup parameters.

There is a smaller hinged storage compartment on the front of the machine for holding consumables, like ceramic cups and tungsten electrodes, as well as different size collets and back caps for the torch. It's great to have these at your fingertips and organized in discreet compartments.

The simplicity of the front panel really caught my attention. Many people are confused and intimidated by the array of knobs and switches most TIG welders have. Miller has provided a lot of adjustability with elegantly simple controls. There is an on-off switch, conveniently located on the front of the machine, and two digital displays that show the settings. There is one (process) knob that can be switched to three positions; AC TIG (for welding aluminum and magnesium), DC TIG (for welding most everything else), and DC Stick for doing traditional arc welding (which this machine is great at). There is a second knob, used for changing the welding parameters, and a push button used to cycle between the functions you're adjusting. That's it. Setup is extremely easy and this machine debuts the "Pro-Set" feature, which provides pre-programmed weld parameters that have been optimized by the welding engineers at Miller for most welding situations. Honestly, the default settings worked so well that I used them for several days before I experimented with the various adjustments available.

"Auto-Line" is another feature new to the Syncrowave 210. This automatically adjusts the machine to any incoming power between 115 and 230 V. The power cord has two interchangeable plugs, one for a standard 115V receptacle and one for 230V. No internal adjustments are necessary; the machine automatically accommodates whatever line voltage it's connected to. It's so convenient to be able to run this machine on 115V; although the maximum output power is somewhat limited, it allows you the versatility to weld in places that only have 115V service (like many home garages or even inside your bedroom).


1. Here's the updated Syncrowave 210 welder, a 210-amp AC-DC Inverter TIG machine that's easy to use. It has excellent default settings and simplified but comprehensive adjustability.

2. Most automotive users weld steel sheetmetal more than anything else, and the default DC TIG settings do a beautiful job for repairs, patch panels, and body modifications.

3. The Syncrowave 210 is ideal for structural welds, too. This is a long miter joint being welded on square tubing.

4. Round tubing requires more torch manipulation to navigate the joints, but with a little practice you can make strong, attractive weld beads with full penetration.

5. The control panel is extremely easy to use, with only two knobs and one push button. Once you select a process (AC TIG, DC TIG, or DC Stick) you can quickly set the parameters.

6. It's challenging to make a weld close to an edge. Here, the edge of the vertical tube has been melted by the nearby weld.

7. Pulsing makes it much easier to weld close to an edge without burning through.

8. Pulsing is very beneficial when welding sheetmetal too. Notice how little distortion the pulsed sample on the left has. Pulsing makes a huge difference, especially on stainless parts like these.