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Thread: Starting out with AC/DC TIG
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30th Oct 2016, 09:36 PM #16Golden Member
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30th Oct 2016, 09:41 PM #17Member: Blue and white apron brigade
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what about a slow leak between the flow meter and the torch?
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30th Oct 2016, 09:44 PM #18Golden Member
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Oh yeah, that's what I meant to say as well - you can buy one of these:
img1394.jpg
I've read some guys like to use them every time they change torches. I've used mine occasionally just to check but I only have two torches I switch between.
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30th Oct 2016, 09:58 PM #19Philomath in training
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Check for leaks with soapy water.
Some time ago Miller put out an 88 page TIG handbook that had some useful background information in it. It has gone from their website (been replaced by a 66 page publication that costs) but someone has posted a copy here https://drive.google.com/file/d/0BzZ...lISVZKMEk/view
I also downloaded the PDFs when they were on the web so if that link goes...
Michael
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31st Oct 2016, 03:50 AM #20Senior Member
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Regarding gas usage, I made a huge difference by dealing with the problem of the regulator outlet pressure. Have a listen to your torch when you press the trigger. Do you hear a big pop while the gas whooshes out. then goes steady at 7 or 10lpm? What happened to me is, the regulator is actually set to give out 25psi (or 50 PSI, from memory, I may have the figures wrong) When you stop welding, the tubing from the regulator through the welder to the gas valve will build up to 25PSI, the outlet pressure of the gas regualtor. Start the torch and the pressurized gas comes out with a whoosh and that is costing you a fortune, especially when you are learning and starting/stopping a lot. Once the pressure in the tubing drops, then the flow meter will set the gas flow, but its that initial purge of gas which is wasteful.
There are various things you can do.
Minimise the volume after the flow meter and before the gas valve in your welder. Some people stick solid tube inside the gas tube to help with that, and keep tubes as short as possible.
There are commercial valves you can fit at the outlet of the welder.
Be a cheapskate like me and drop the pressure of the gas regulator. I set mine very low but I suspect this will change the accuracy of the flow meter. From memory the cheap flowmeters work on known pressure drop across an orrifice. It still seems pretty good though. The biggest disadvantage is you need to adjust the regulator as the cylinder pressure drops. If you don't, the flow rate will visibly increase, so its kind of fail safe in that way. i think you might need to adjust the regulator maybe 3 times during the bottle life.
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31st Oct 2016, 10:56 AM #21Diamond Member
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When I turn off the gas bottle, it holds almost full pressure in the line to the welder for a day or more, so I believe from the bottle valve to the gas solenoid is fairly airtight. Then there's just the quick-connect at the welder and the torch. I might try the soapy water.
And I'll check for the "poof" - that's certainly something I get on my MIG setup, but I don't think I've noticed it with this.
As my E size of MIG gas still hasn't run out, I'll go get me another Bunnings D size of Argon. When it comes time to swap the E size, an Argon refill from Gasweld costs $155 for 4m3, versus $198 for 4.2m3 (2 x D sizes from Bunnings). That works out at $38.75 per m3 versus $47.14. That said, if the Bunnings option had been around way back when, I think I'd have preferred that option as even with the higher cost, there's a lot more flexibility, and you can get your deposit back if a better deal comes around, whereas I think I'm stuck with my Gasweld bottle, unless I sell it on Gumtree.
Convenience-wise, at the rate I'm using Argon, an E size will probably be more convenient for TIG use, and it also tends to stay in the workshop (well, so far), whereas the MIG unit often goes on trips outside or to other locations.
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31st Oct 2016, 10:57 AM #22Diamond Member
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Should also check out this Gas Lens business - I assume it only fits to one of these CK torches, not to the one that I got with the welder?
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31st Oct 2016, 11:13 AM #23Golden Member
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The gas lenses should be standardised, I assume. I dunno, I'm CK all the way. But it's probably just standard threads that fit any "size whatever" torch. The head parts are only maybe $50 all up, for one lens kit. BOC rebrands the CK stuff but they don't have much range and for whatever reason they don't seem to sell the 2.4mm size, which seems stupid to me since it's the most versatile. I've just bought a couple of big shipments from the USA direct each time I bought a new torch (e.g. the torch, the lenses, the consumables, everything required for that particular torch). The CK wedge collets are good too. People say regular collets wear out but I've not experienced any wear out with the wedge collets. The CK superflex cables are really nice too. As are the flex-loc torches (that's what I use 99% of the time). OK, enough free advertising. The only thing that sucks from CK is they have so many options that it's hard to decipher their catalogues until you get used to them, but their customer service are very helpful if you need advice.
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31st Oct 2016, 06:40 PM #24Diamond Member
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Picked up a new D bottle of Argon, and a gas lens kit from BOC - $22 for the 2.4mm version - fitted my #26 torch just fine. Since I'm welding on the bench I'll wind the flow rate down to around 5-6lpm and see how things behave.
Also discovered Jody has a series of TIG tips online - much faster to read through than watch a video!
Tig Welding Tips
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31st Oct 2016, 11:19 PM #25
Yep 5-6ltr per min is oodles for most work, to much can suck in air with it apparently.
All good brands use the same torch parts just need to stick with what series torch you have.
Ive lashed out and spent some coin at Weldfabulous on a CK 225 (20 series with 25' of superflex) by the time it was landed on my doorstep it was over $700! But its money well spent its night and day compared to the one that come with my machine (wp18 with 12' of anaconda sized hoses)....................................................................
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1st Nov 2016, 05:38 PM #26Golden Member
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I think every single person who starts out with TIG welding gets a big surprise regarding gas usage. This was what was behind my comment earlier in the thread about some professional instruction being well worthwhile - just for the gas it would be likely to save.
The good news is that the amount of gas you use goes down dramatically after you learn and stop practicing. Part of the reason is that you do in fact turn your gas flow down as you are more attuned to what is affecting your weld quality and you can optimise. Gas lens, smaller cups, tight arc, short stick out, better torch angle, longer welds etc. all mean that you can use less gas - but there is a point where the risk of stuffing up a weld (particularly with Al) is not worth it.
Watch out for breezes (and fan exhaust from your welder), which will blow away your shielding - which then makes you want to turn the gas up.
Cheers
- Mick
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1st Nov 2016, 08:47 PM #27Diamond Member
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When I think about it, TIG is an inherently slower process than MIG (well, at least for me) so you're always going to use more gas for the same length of weld, but hopefully the changes I've made should improve things.
I'm going to prep some 30x3 flat steel bar, chop it into 100mm lengths and practice a bunch of lap joints - I like these as there's the challenge of balancing the heat into the flat without chewing into the edge of the bar on top, and getting a consistent bead size. I've only got 2.4mm tungsten and filler, but I'm hoping with a sharp point and a tight arc I should be able to get a puddle in the root that doesn't spread too wide.
I'll post pics if the results aren't too dreadful.
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6th Nov 2016, 10:33 PM #28Most Valued Member
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Ahh there lies my problem of chewing thru gas like no tomorrow!!!! i have a little Mechpro 140A DC TIG from Repco i never really thought about the gas building up inside of the torch hose and the hose inside of the welder but i too hear a loud whoosh as i open the valve on the torch before striking a arc, i just assumed all TIG welders with a gas valve on the torch would act the same
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6th Nov 2016, 10:41 PM #29Most Valued Member
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I have noticed that too but only on aluminium Rusty, my arc's are wide for some reason and it contributes to a hard weld, i have also learnt how to TIG from Youtube videos and members on here MWF but what i see in the videos on youtube of the close up arc's are they are tiny arc's and well behaved like in this diagram
i thought it may have been just me but after reading your post it seems we see the same thing
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6th Nov 2016, 11:09 PM #30Golden Member
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gazza, I have an automatic solenoid machine and get the gas whoosh. I have a single hose with the electrode running down the hose somewhere so I'm reluctant to stuff anything down there. The only time it has an effect (besides gas usage, but I use a G-ish size so I don't care too much) is the very first weld of the day, when non-argon crap is in the hose. I always stomp the pedal once at the start of the day before welding to evacuate all the air.
Regarding the arc, two things contribute to a tiny arc:
(i) a small electrode
(ii) a sharp electrode
I use a 1.6mm electrode for anything below about 120A. It helps a lot. Sometimes I'm tempted to use a 1.0mm too. A sharp 2.4mm is OK on low amps but it needs to be sharp. Sometimes you'll read material (from reputable sources) about how an arc is more penetrating and direct with a blunt taper. Maybe, but I get way better, more controllable arcs from a sharp, small electrode than a blunt or bigger one. And I generally follow the 2.5-3x diameter/taper rule.
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