Tig welding tips, questions, equipment, applications, instructions, techniques, tig welding machines, troubleshooting tig welding process
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Thanks, RedIron,

I haven't any questions yet, because I've not had the opportunity to try it yet. 99% of the time I spend welding (which is maybe 10% of my work hours, these days), is on 304 SS, sch.10 down to .049 wall tubing. Because of an odd set of circumstances, and my odd combination of skills and experience, I've become the de-facto first-line supervisor, lead vacuum tech, lead ASME vessel retest mechanic, and the list goes on. I'm only called on to weld for critical repairs, and complicated valve change-outs. This actually means I'm usually "out of practice" when I'm called on to weld.

I WILL find some free time or a good excuse to try my hand at this, though. The logic is sound, the results are clearly sound, and I love adding another skill to my resume'.

Steve S.
nova_70_383
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this is very interesting! do any of you think the same results could be had by running AC 99% electrode negative?? many of the new inverters can go 90% or higher like the dynasty 700 i use at my work place.
Ballinator
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Hi Bryce,

It's refreshing to hear open minds thinking outside the box.
Would you tell us what your machine settings are?
Especially polarity, gas etc..

Thanks,
Don
bryce39
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Sure, this setup for 1/4 aluminum plate was run with DCEN with a gas lense, 3/32 2% thorated tungsten sharpened to a point.
I like the gas lense for the even flow characteristics of the gas, minimal turbulence.
Straight Helium was used at about 15-20psi
Machine was set at about 180 amps as I like to have the option for more heat control in the pedal but actually 150 will do just fine
The machine was a miller 300 and gave you the option for clean, penetration or balance----------set it too balanced
Clean the material including your rod with acetone, brush material throughly with a stainless steel brush and then wipe again with a clean low lint wipe
Preheating the material is recommended, but I did not do that in the joint in the picture

The thing is when you clean aluminum this good, you dont need any AC for cleaning ability. Whatever you weld in life no matter what it is, it will always, always be a better weld with proper preparation including cleaning. I cannot stress this enough, the cleaner the better.

This old man I worked with years ago used to tell me that if you start with a turd you will end with a turd. Polish it all that you want but the end result is going to still be a turd, lol
Welding was created for people by people that think outside the box!
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I had assumed the "very clean, and right now" part.

You specify 100% helium (available to me, no issue), but at a PSI, rather than a CFH. Are you using a dry rig with a gas valve?

I've used helium as a percentage of my gas with excellent results.
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BTW,

The phrase, "You can't polish a turd" has been a part of my life for years.
bryce39
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Sorry CFH, the torch is water (coolant) cooled.
TamJeff
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I used DC to build an aluminum T-handle for one of my offshore fishing reels. I used DC because I only had 2% and pure tungsten on hand and wanted to use a sharpened electrode for tiny welds. It was more like tacks on tacks than a full on weld being as I pulsed it but it came out quite nice and held up fine. I still have the reel. Never did bother to buy a replacement handle.
Miller ABP 330, Syncrowave 250, Dynasty 300 DX.
Honorary member of the Fraternity of Faded Tee Shirts.
xivlia
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Hello guys i just registered here so i am new and i am a total beginner. in fact ive only used MIG once, and no experience with TIG at all. now i know what some of you may say... that its too dangerous or not worth trying, but i am currently in the middle of a project and i need to weld some 3mm aluminium sheets. i was planning on buying this 3 in 1 system because i also need a plasma cutter and this comes with it.

http://www.aliexpress.com/item/50A-Plas ... 19410.html

will this be okay to do small amounts of welds on alu sheets? the length of each weld will be something like 4cm long at most. hope you guys can help me out :) cheers.

my uncle is a professional welder but he doesnt have his welders with him, hes taken them to his work abroad, so i cannot get him to help me.
xivlia
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no help from anyone?
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Hey,

Hang in there mate. Someone will have something for you. I have about zero experience on Al so i shouldn't give any advice, but because its the festive season, other regular contributers may be off line. keep checking in and someone will help out.
Mick
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Hi, xivlia,

If the machine meets it's claims, It'll be more than adequate for your plans.

I can't speak for this particular brand, but I can make two general observations:

While many Chinese-made welders are not ready to compete with their established counterparts, they have been steadily improving.

The price for the fuctions offered seems a little low to me. In your place, I'd try to locate a few folk who already own it, preferably experienced weldors, and ask for their reviews.

Steve S
xivlia
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hmm i understand, i will try and see if anyone has got one of these. i have one more question.

those chinese welders are DCEP, it shows the torch as + and workplace as - on the machine, will it be possible to reverse the polarity? will it damage the machine? or does it not matter
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It must be possible to reverse the polarity, as DC TIG is always DCEN. It might be automatic with the machine settings.

Polarity is a non-issue for Aluminum, as it's AC.

It might just be the way they've chosen to mark ground (workpiece) vs. electrode.

Steve S
xivlia
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ah okay, i was just wondering and i didnt know if TIG machines are made to be specifically one way ie, DCEN or DCEP. i didnt know you can alternate between them even though it has + and - marks on the machine.
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Well reading this really hasn't improved my mood...
The first half of day two was spent at college trying to learn how to weld aluminium on DC by mistake. I was using 100% argon and i was convinced i'd got horrendous contamination judging by the black crust on the weld. Which is why i bought a stainless wire brush and acetone for the following night.
Of course, the following night i discovered that you weld stainless on DC and not AC. All became clear then as i realised i'd been welding on DC all night as my stainless welds looked great :oops:
So as it stands now, i now know i can't weld on either polarity :(
Can't wait to try it the 'pause-lift-dab-down-forward-pause etc' Jamie method though :D
ESENTI
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Dear Friends , I would like to make a little note here , I had a 160 Ampere DC only machine and I had to stick with it for many years before I buy an AC /DC machine .
Any way I had to weld some aluminum jobs and I tried this , I took stick aluminum electrodes Si 12 the 4043 it has 5 %Si and I weld with DC and argon
At normal flow or a bit less . The heat of torch melts ( 2 % thoriated RED 2.4mm ) the aluminum base metal the paste also melts and cleans the surface of aluminum oxide then melts the stick electrode core which is aluminum eventually it mixes with the base metal puddle . The quality of the weld is poor and you also have to remove the paste that solidifies as you do with stick welding with a chisel .
I also know that OTC a Japanese welding machine combines AC with DC so at
Tig process AC cleans for few secs then DC takes its place at this point you add the filler metal . It claims that melts a lot better and nicer than the traditional AC only machine.. So I think that Helium can work and it a very good idea that i think it is interesting well done ...
ESENTI
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I'll have to explore that OTC machine you mentioned.

It makes a lot of sense, if set up like pulse. Say, a second of balanced AC for the cleaning, with a burst of DC for penetration? Or even a thumb-switch... AC until you're ready, press the button and feed the rod under DC?

Interesting concept.

Steve S
ESENTI
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This is the short description for the OTC manual as you might like to see Dear Steeve the machine is OTC ... DA-300P this is from the manual ...

ESENTI ...
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Thanks, ESENTI,

That's what I was thinking you meant. What you just shared suggested it for an automatic (semi-robotic) process, but I can see manual uses for it, either by learning to work with the preset rhythm, or with a manual switch to activate the DC mode briefly for filler-feed.

I don't get enough aluminum work to justify a purchase, but, we're expecting a Miller SW250 back that the repair cost was too high for (we bought a new one instead), and I'll be able to experiment with it at will.

Steve S
ESENTI
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Steve , It says mostly , it can bu used in either way by a welder manualy or automation , and the machine does it itself I canot see how you can do it in a machine that has not been desined for this .Switching ac to dc is imposible while you work on an aluminum it remains only theoritcal aproach at the moment ...
I dont know this model and in my area is very rare to see MIller Machines,(Europe ) even that i know that it is represented it in Italy ..
but i know that are very good machines ...I have Fronius magic wave 220 ...Which is i think even better ...

Esenti
BDoubleU

I'm jumping in a little late on this discussion ... but wanted to share a pic of some DCEN w/ helium on aluminum. Originally, TIG was trade-named HELIARC because the process used DCEN w/ 100% helium. But, today AC is the most common and preferred method for most applications ... it produces good results and argon is cheaper than helium. But, the application in this photo would not allow for any surface "etching" caused by an AC arc ... so it was welded with a Miller Aerowave in DCEN. The edges of the weld look a little smokey - but otherwise they turned out pretty sweet.
Brent Williams Aluminum DCEN with Helium.JPG
Brent Williams Aluminum DCEN with Helium.JPG (25.37 KiB) Viewed 4497 times
weldfusion.com
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That's slick, Brent!

I have access to all the (high-purity) helium I can use, and have yet to have an excuse to try this. It's coming...

I have used He/Ar, at aprox. 50/50 on HFAC aluminum for thick sections, and the difference is impressive!

Steve S
RedIron881
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Telling yeah it works great if the settings and the hands are there. Plus, it's nice and quiet, ha ha! Thanks for sharing Brent.
kiwi2wheels
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Any doubts about the quality of aluminum welds done with DC and helium should be forgotten. Short runs, peen and allow to cool, repeat.

All Rodeck top fuel dragster blocks and heads are repaired with DC. Also many historic auto race engine blocks, e.g., DFV Cosworths

Pioneered, or perfected, I believe by ; http://en.wikipedia.org/wiki/Epperly
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