The welder selection decisions?

[7milesup]

My instructor in the TIG class that got cancelled halfway through, described TIG welding as like patting your head and rubbing your tummy while trying to tap your toe to the beat. I found that a pretty accurate description, there is a lot going on. I need a lot more practice to get past barely marginal at it, I can't dance either.

Very true. I can't dance. Can't rub my head and pat my tummy, or is that the other way around. See, I am an uncoordinated mess. But, I actually can TIG weld. Not like the dudes that walk the cup and make us in awe of their skills, but mine isn't bad.
One of the little tidbits that I picked up watching a welding video somewhere was to move your TIG torch 1/3 of the puddle and then add your filler rod. Rinse. Repeat. I was trying to figure out how to "stack dimes" and it was a cursory comment in a video that had a nearly sea-change result in my welding.
Here are a couple of pics of my TIG welding. Not pro quality stuff but OK since my TIG instructor was crap and taught me nothing. You Tube has been more help over the last year or so. First is aluminum, second is steel.

 

[pontiac428]

It takes about 220 amps with an .045 flux core wire and tri-mix gas. Actually with the tri-mix you can go down to 200 amps before you need to switch to a finer wire if your welder can feed fast enough. I use Praxair Stargold STR-2 for gas and nothin' fancy FC-E71 for wire. You could use stainless or silicon bronze if you wanted to. The nice thing is this setup with small wire will let you weld out of position in spray mode.

When you are doing wire welding on big stuff, you need to be able to get filler down fast. The method creates little spatter, mostly during start and transitions. During spray, the filler never touches the base. The tri-mix gives a better arc penetration profile for a (relatively) smaller puddle and a deeper weld. The best part is spray transfer welds look very nice.

 

[General Zod]

Do tell about spray transfer deposition?
OK - I guess I can search on YouTube to learn about it, but I want to discover if the technique is exclusively the preserve of large firm industrial processes.

"Lunchbox welder" as for perhaps stitching some car body at 85A, or welding up a bench frame at 120A, I can understand, might be out of their league.
What minimum capability in a welder is viable?

I would say it depends on the welding process.

For a 90° T-joint..

Stick welder using E6011 rods = you can weld up to ¼ " in a single-pass with only ~100-120A.
MIG welder trying to weld ¼ " in a single pass = you need ~180-200A !
TIG welder trying to weld ¼" in a single-pass = you need about ~ 220-250A!

As you can see, you get the most "bang for the amp" with stick welding, albeit E6011 is not suitable for every single application I might add. E7018 is more versatile, but even then you'd only need about 150-160A with a 5/32" electrode to weld ¼" in a single-pass. Still a pretty good value for the electrons needed.

My cheapest [stick] welder cost me $65 shipped on Amazon. While starting the rod is horrendous, once it does get going, it actually does work. Puts out ~ 112A and can weld ¼ " with a 6011.

 

[graham-xrf]

Some things that need decoding/explaining..

SYNERGIC? I think in relation to MIG
TIG LIFT ? I know it's something other than simple "scratch-start"!
UP-SLOPE and DOWN SLOPE ? For a beginner - no, it's not about the way the surface was tilted. Something to do with waveforms?
ARC FORCE ? Is that "control of"?
HOT START ? Why is that a thing. How that changes the machine value ? You start sometimes from cold. They all have to start somehow.
and..
What is the deal with SPOOL GUNS, and welders that feature "ability to attach spool guns"?

INDUCTANCE ? The adjustment thereof, and how, and why? Automatic electronic control thereof?
I know what inductance is, as being the magnetic storage property of coils and magnets that sets the rate of change of current.

 

[General Zod]

Some things that need decoding/explaining..

SYNERGIC? I think in relation to MIG
TIG LIFT ? I know it's something other than simple "scratch-start"!
UP-SLOPE and DOWN SLOPE ? For a beginner - no, it's not about the way the surface was tilted. Something to do with waveforms?
ARC FORCE ? Is that "control of"?
HOT START ? Why is that a thing. How that changes the machine value ? You start sometimes from cold. They all have to start somehow.
and..
What is the deal with SPOOL GUNS, and welders that feature "ability to attach spool guns"?

INDUCTANCE ? The adjustment thereof, and how, and why? Automatic electronic control thereof?
I know what inductance is, as being the magnetic storage property of coils and magnets that sets the rate of change of current.

Synergic

• The (MIG) machine is programmed with a set of data points. The user decides the WFS, only (or sometimes by a material thickness, which really sets the WFS anyways, just via a different "visual"). The machine matches up the chosen WFS to a pre-programmed voltage that has been decided by the manufacturer, using what ever protocols they decide to use. Most machines will allow fine-tuning of the voltage from there using either an "± offset" (whose units are volts), or a multiplier (that is unitless, and serves to reduced/increase in a similar fashion as an offset). Machines can vary greatly in this respect. The Millermatic 215 sets ¼" parameters to about 450 ipm / 25V. My MIGs set the same material thickness parameters at a much hotter 629 ipm/29V !

TIG Lift arc

• The tungsten is touched to the work, the machine senses this, and then electrically turns the tungsten "hot" as it is lifted off the work piece. Very similar to scratch start, but it is much more controlled since it relies on ramp-up rates programmed into the machine.

Up/Down Slope

• Controls the rate of current rise when an arc is intiated/terminated. For added control, versus abrupt on/off scenarios.

Arc-Force

• Applies to SMAW stick welding. The addition of arc force increases the current for the operator (with no intervention) when the tip of the electrode is brought in very, very close to the work. When that happens, the arc voltage drops a tad, the machine senses this, and increase the amperage to prevent sticking the rod into the weld puddle. Again, all for added control and manipulation of the welding arc.

Hot-Start

• Primarily a spec for SMAW (but some TIGs and MIGs also have this in another capacity). The tip of the stick electrode does not want to easily emit/receive electrons when it's cold (look up: thermionic emission). That's why sometimes it tends to "stick". Hot start can be used to help the rod light up and function as an intended electrode by increasing the amperage output for either a pre-determined or user-programmable set-time and amperage increase.

Spoolguns

• Used to feed soft wires, primarily aluminum, from a small spool installed directly in the gun.

Inductance

• Used in MIG for added control of the welding arc. Some machines dial it in/out differently, but inductance affects the current-rise on the short-circuit event. On one end, the arc & overall "feel" is very "smooth"; the puddle is more fluid, wets out easier, and there is less spatter. On the other end the arc is "cripser", there is more slightly more fine spatter, but there is added control due to the puddle 'staying in place' a bit more. The former resembles more of a situation where the short-circuit events rather "blend in together" more, and the latter has more distinct, separated, short-circuit events. The difference is also audible; the former is a smooth "buzz", and the latter is a harder, distinct "BBUUUZZZZZZ!!". Best way I can describe it.

 

[Aaron_W]

TIG Lift arc

• The tungsten is touched to the work, the machine senses this, and then electrically turns the tungsten "hot" as it is lifted off the work piece. Very similar to scratch start, but it is much more controlled since it relies on ramp-up rates programmed into the machine.

Just one comment to add on this, (High Frequency (HF) start is a no contact starting method. Scratch start and lift start both involve touching the tungsten to the material. Since any contact with the tip of the tungsten introduces the possibility of contamination, HF start is preferred. A new machine that doesn't have HF start is probably on the lower end of price / quality.

 

[graham-xrf]

My trawl through (many brands) shows a pattern of dedicated MIG machines, and a another MIG set which offer a TIG-LIFT control. Even so, TIG seems to be the poor relation. Price-wise, many of the deals are confusing, because of the noise of other stuff in the bundles. Helmet, gloves, empty cylinder, spool gun, reels of wire, etc. but the TIG capability may require the separate TIG torch, cups, and kit not included in the bundle.

Then there is the whole class of TIG machines, offering TIG/MMA, RF start, etc. They seem to cost at least as much as MIG, and more, and, of course, don't do MIG.

I do get the impression that TIG is great, but takes longer, uses more gas, has it's own skill/learning curve, and the dedicated machine costs more.
Basically, if you want to get the best out of it, get the best MIG you can afford first. This might let you try TIG if it happens to offer TIG-LIFT.

There has to be a reason there are sophisticated current waveform control TIGs out there, which cost as much and more than MIGs.

The routes to welding aluminium can be had with both MIG and TIG, but in different ways. TIG-LIFT is not, apparently, something that can be done with aluminium. If the machine is a dedicated TIG, and happens to be for aluminium, then RF start is used.

I would love to do TIG, but the practical consideration is that the first welder should probably be a decent MIG.

 

[Aaron_W]

If it helps I like having TIG available, but I wouldn't want to be without a MIG welder.

I never did much welding before 2018, and that was mostly in high school, so a little stick and oxy fuel. I didn't know what I was missing.
If I had to start over a good MIG welder and horizontal bandsaw would be among my first major tool purchases after basic hand tools, and some core carpentry tools. I still have stuff to do around the house that requires working with wood, so the welder has to get in line but it is a short line.

It was like going from using a hammer and nails, to screws and a cordless drill or a pneumatic nail gun (also tools I'd hate to be without).

 

[General Zod]

I would love to do TIG, but the practical consideration is that the first welder should probably be a decent MIG.

If I had to do it all over again, I'd tell the old me to start to learn stick welding on a good stick welder.

 

[graham-xrf]

About MIG voltage ranges
When comparing two MIG welders, same supplier and brand, and pretty much the same specification, the only thing I can see different, aside from a minor change in the display style, is in the voltage ranges.

Machine #1 (Sherman DIGIMIG 200 SYNERGIC) ($773.35 USA or £574.00 UK)
Three modes 7V, 5V-24V, and 7V
- - - - - - - - - - -- - - - - - - -

Machine #2 (Sherman DIGIMIG 200X SYNERGIC) ($755.84 USA or £561.00 UK)
Two modes 15V, and 5V-24V
- - - - - - - - - - - - - - - - - -
They have identical, copy-paste main features blurb. Letter for letter, all texts are the same.
In the Item Specifics list, I can see that SPOT WELDING is mentioned for the cheaper machine #2 only

Main features:

• - Automatic parameters for MIG
• - High duty cycle ( 60% at 40 degrees Celsius)
• - Program for aluminium welding
• - Adjustable inductance
• - Settings memory
• - Spot welding - on Machine #2
• - Fan stop
• - 2T / 4T
• - Welding voltage correction
• - Burn back control
• - Overheat protection
• - Gasless welding
• - Hot start
• - Arc force
• - Anti Stick
• - VRD
  - MMA welding process
• - MIG welding process
• - TIG DC Lift welding process
• - Brazing

I would be great to discover what is the deal with the different voltage modes?