Pulse GMAW Ali thicker plate

Hi there
Having a difficult time with Pulse-GMAW of Ali in greater thicknesses.
Compared to previous happy times where after a very few days I'm
considered the master of the job.
Do not have yet a "model" or "multi-dimensional map" giving a
rationale of where to find the best conditions for new situations with
Pulse.
Previously I've used
* spray transfer for anything >=10m/min wire-feed-speed
* pulse only for thinner low heat demand things like outside-corner
welds sealing end-cap plates onto Al-Si-Mg 6082 extruded Rectangular
Hollow Sections
So I'm trying to Pulse where previously I've used spray.
Thicknesses...
Mostly 5mm (in 5083 (marine Al-Mg) plate)
(*
(/ 5 25.4) 16) 3.1496062992125986
which is just under 3/16" plate thickness.
So not great thicknesses (done 1/4" sections to 3/4" plate Ali before)
The machine has two knobs at the wire-feeder.
One increases the thickness it is supposed to be welding on - and it
reports the Amps go up seemingly in proportion.
The other is a "trim" which might be related to Voltage?
I only have a list of welding conditions which worked in specific
cases.
I wish that like eg. doing any spray-transfer I have a "map" of
the "contours" of good conditions and can see from a small test weld
where I am in the "map" and have a very accurate guess of where I need
to be to land on good conditions for a new previously unfamiliar job.
I have seen very good welds where I would be using Pulse anyway, so
don't doubt the machine (well, I've seen others sink into
"anglo-saxon" borrowing it and finding glitches, but anyway...)
I sometimes end up with good welds but fillet sizes bigger than called
for because there simply does not seem to be the fluidity to run beads
at the minimum size.
So - Pulse GMAW Ali (aluminium, aluminum) - anyone point me to a way
of seeing an overarching sense for it?
Build that "multi-dimansional contour map" to know where to look for
the good conditions in any new circumstance?
Thanks in advance
Reply to
Richard Smith
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Again all I can offer is my absolute neophyte experiences. I have zero experience with pulse MIG. I simply can not afford/justify the cost of a nice pulse MIG rig, and none of the import machines quite meet my minimal requirements for that. I do have a fairly decent Miller continuous DC MIG welder with just two electrical adjustments. Well not counting the on/off switch. (I own my own shop doing mostly CNC milling aluminum N STUFF)
I will repeat something I have come to believe. Pulse is primarily to allow for heat management, (I could certainly be wrong), or to allow the welder(person) to keep up. Thicker aluminum needs a lot of juice or a substantial preheat. By thicker I mean anything thicker than about 5/16 (8mm). I personally found I could run 0.100 (2.54mm) to 1/4 (6.35mm) aluminum fairly easily (I made welds that stuck) without preheat. It was mostly a matter of finding the right speed to move the gun, and it had to move. Thinner was touch and go for blow out for my skill level (this is where I believe pulse might be helpful) and thicker just wouldn't weld without preheat.
To me it seems counter intuitive to use pulse for thicker aluminum. Again. I am open to being wrong.
The magic bullet (so to speak) I have not tried is other gas mixes. I have three main welding gas bottles. C25 for steel, Argon for MIG aluminum, and Argon on the AHP200(XXX) TIG. I have heard of helium being added helping a lot for thicker aluminum, but I have not researched it at all. Just seen casual mentions on the various YouTube welding channels. I suppose I should learn more because it might be helpful to repair minor damage to an aluminum mold instead of scrapping the part and starting over. Since the minimum plate thickness I normally use is 1/2 inch (~13mm) I would consider that thicker than I can repair easily by welding. When I just learning and only making molds for myself on the old Taig mill I actually did fill in some holes with MIG, but it was pretty terrible and require multiple retries to get something that "worked."
Maybe there is something in there, but somehow I don't think I've come anywhere to close to what you already know.
For my applications I thought of pulse as a way to (maybe) make longer stitches and longer fills when doing stitch and fill welding on aluminum sheet. Still.. I am open to being wrong. Of course one of the main reasons for stitch and fill is to lock the pieces to each other and reduce uneven movement and distortion of the work pieces.
I wish Ernie was still a active on this group. He would have very much been able to help you.
Reply to
Bob La Londe
Bob - I'm otherwise busy, but on a skim-read I think you are talking a lot of sense. I didn't want to be leading - wanted to see the responses coming in - but if I were to take a guess, you've covered well over 50% of anything I thought.
Reply to
Richard Smith
By the way... Another major contributor to this group, Randy Zimmerman, died in mid-November. Bless. He was in his mid-70's and was spared a lingering demise from what we call "Motor Neuron Disease" (I think the North American name is ALD). I owe a lot. Others may feel the same. Thoughts with his family.
Reply to
Richard Smith
I haven't tried Ali with a copper-and-iron GMAW / MIG welding machine. I suspect a good one would be very good for spray-transfer Ali. The consistency, and the way that the "operating map" of a copper-and-iron machine is well known...
That is what I am wondering is exactly right, and the main point behind my entire question?
Pure Argon is so much cheaper than any Helium mix. Only in the USA do you seem to have any affordable and frequent use of mixes with He. Here - forget it. Especially as I have done up to 20mm (3/4") Ali plate with pure Ar and spray and it gave the "dream spec." welds.
Indeed.
I've responded back to you because of the considered effort. I'd like all to be provisional, on seeing if more answers and / or comment come in. Be ready to benefit from range of wisdoms.
Reply to
Richard Smith
The Miller 212 is setup with dual bottles, dual regulators, dual solenoids, and dual stingers. There is a regular mig gun on one, and a spool gun on the other. It was always intended to be used for both steel and aluminum. Its easy to switch too. Set down one stinger and pick up the other. In theory I could have the work piece clamp on the table and switch from steel welding to aluminum welding that easily if the settings where close enough. I'm not very good with it, but if I take a practice run on some scrap I can usually meet my minimal specification.
Reply to
Bob La Londe
I wanted to be open-minded and watch independent response come in.
Okay, my thought is
"Where, compared to spray, pulse allows you to have spray-like characteristics while keeping the arc intensity and fluidity down, when you are trying to find ways of making pulse give you spray-like fluidity you need in this application, why are you using pulse and not using spray?"
That's another way of saying what you said in your first response, isn't it?
Additional points * spray is very smooth - no perturbation of the weld pool (no spatter; smoother weld bead finish; better control; etc.) * simpler equipment * very finely tunable * very easy to comprehend what the adjustments do * transportable between welding machines - spray is a fundamental mode entirely governed by the Laws of the Universe, and barely by the characteristics of the welding machine (?)
That's a genuine question, everyone.
I can't try spray because of the "house style" conventions, else I'd know the answer already...
Just stating the obvious - when pulse is what you need because the job needs a lower arc-energy than spray can go down to (thin, outside-corner, etc.), pulse is a blessing with no criticism possible (?).
Reply to
Richard Smith
I think this group just doesn't have many experts such as yourself any longer. I believe Ernie has a Facebook page where he still shares his expertise, but based on responses to my own queries there are only a few here on Usenet still willing to help. When I was first really trying to get over the hump so I could chicken poop some metal together and dry the poop before it fell apart I would post exact problems here and often have a handful of very close overlapping recipes to start from. Current, settings, wire feed, gun speed, etc. I think that day is past. Now if I have a technical problem with a weld I'll check the usual YouTube video experts (Weld.com & Welding Tips & Tricks are both good) to see if they have something that overlaps what I want to do, and then I'll ask a carefully crafted question on the Miller Welds forum. Internet welders are an independent lot (like Internet machinists) and often refuse to answer the question you actually asked.
Reply to
Bob La Londe
Thanks for the hints. I try to post questions of s.e.j.w. first, to give it a chance of enduring. But yes, I have posted and got nothing. r.c.m. (rec.crafts.metalworking) has more active welders. I'll look in those forums.
Reply to
Richard Smith
I try to post questions of s.e.j.w. first, to give it a chance of enduring. But yes, I have posted and got nothing. r.c.m. (rec.crafts.metalworking) has more active welders. I'll look in those forums.
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I try to help when I can, but my MIG welding skill is barely adequate to let an old car and truck pass inspection. I've heard that manual and writing skill occur together even less often in Britain than in America.
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-jsw
Reply to
Jim Wilkins

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