Hey, Jody,

I love to see the arc force flowing the front of the puddle into the root, and your close-up arc shots show that to perfection.

Now, about melt-through, or nipping the backside. If I saw that in just the odd place, I’d know that it must have been due to a lack of consistency. I noticed at one point you said that you were pushing the wire in to avoid melt-through. If lack of consistency wasn’t the problem and melt-through was in more than the odd spot, I’d look at the following:

Current setting too high.

Arc not tight enough.

Torch angle not equal.

Not enough wire feed.

Lingering too much.

Is there anything else you would add to that list? I haven’t listed increasing the filler wire diameter because that could bring added problems in chilling the puddle too much.

Martin

JODY COLLIER Hey, Jody, I realised I hadn’t asked about the next step after determining that the aluminium alloy you’ve been presented with is indeed weldable. Still knowing nothing about the base alloy composition, how would you go about deciding which grade of filler wire to use? (If you had some scrap of the same grade of base metal, you could at least test the strength of your intended filler, but you can hardly do that on another part of the customer’s forging/casting.). You made a great video not long ago on “basic TIG metal selection”, but, in it, you knew the grade of the base-metal aluminium before you started. In 2 other videos “TIG welding repair & tips and tricks for metal identification.” and “titanium welding fubar” you used a grinder to help identify the base metal. But you can’t do that with AL alloy. Is there perhaps an aluminium equivalent of 309L? How would you choose a filler for the unknown, but weldable, aluminium base metal?

Thanks

Martin

Brad Goodman Many thanks, Brad; I really appreciate that. Martin

Thanks Brad for pointing me to this in the Live Chat with Jody. Makes perfect sense, but I need to understand how you, personally, use the independent EN and EP adjustment.

After watching this video, my conclusion is that this setting is a fine tuning setting. So, if my inverter had this setting, I’d set up AC Balance as usual, and leave the independent setting set at zero or the mid setting. Then, if I needed more penetration, or felt the tungsten was excessively hot, I’d alter the independent setting to reduce EP to the point where the cleaning action was about to be affected.

So, I feel this is a setting that you could easily live without, getting the same effect by juggling about with AC Balance and the main current setting, but if you do have it, it could be a real time-saver, allowing you to give a simple tweak to this independent setting, without having to make any other adjustments. Is that right? If not, how do you set it up? Thanks, Brad.

Martin

Thanks for this. Mine is the 28th edition, and I see that the book’s now in colour, so I’ve ordered a new one from the US

Jody

A question for the Live Call on unfamiliar machines.,

Advanced TIG welding machines have a current-offset setting, allowing you say to set a different AC positive peak to the AC negative trough. So you could have, say 35 amps peak on the positive portion, but, say, 70 amps on the negative portion. But is this overkill; AC Balance already allows you to set the proportions of the duty cycle where the current is positive and negative ? So, you set AC Balance say for 35% cleaning action, as you might for a typical machine where the positive peak and negative troughs are symmetrical about the zero-current axis, and then you mess it up by playing around with current offset, or am I missing something? Is this another occasion where an advanced feature setting can bring more confusion than benefit; is it an unnecessary feature that’s included to justify the high cost of a machine?

Perfection! Thanks, Jody.

Thanks, Matt: I’ve been waiting for this video. You must have learned to weld on pre-inverter welders (DC generators and transformer-rectifiers), which allowed you to alter the shape of the power (volts-amps) characteristic, from constant current (vertical “curve”) to a drooping/flatter curve. Such a characteristic allows the operator to control the heat input more (by changing the arc length slightly) for out-of-position welds. Some top-of-the-range inverters now let you alter the whole characteristic shape, but the average inverter is constant current at all arc lengths. This is where arc force/dig comes in. It’s a very poor attempt to mimic altering the shape of the whole voltage-current characteristic by giving a boost in current (0 to 100% depending on the dig setting AND the maximum, limiting, current output of the machine) but only at one arc voltage. So it merely puts a kink in the vertical, constant current line, rather than gives it a flatter shape. To be cont

Continued from earlier post…..

So on these typical inverters, dig is less about changing the shape of the characteristic and more about a feature to stop the electrode sticking if the arc gets too short. But if you follow Jody’s golden rule of stick welding, it shouldn’t stick anyway: set the current high enough so that you can keep a tight arc without sticking, and then keep a tight arc. So that’s why you could jam the electrode in at high dig without sticking, and also why the results were not like night and day. So, with a high dig setting and welding with a very tight arc, you’re simply welding at a higher, but still constant, current; if you then back off to a normal arc length, you drop back to the current setting you set up at the start.

This is how I understand it; I’m keen to get your feedback, especially with possible difficulties some people might experience with out-of-position welding using an inverter with some rods (6010?).

JD Brewer well, it was good to see the difference it made, not brushing and brushing. So it was a good demonstration of the benefits. Thanks, JD.