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Forum Index : Other Stuff : welding gas
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| brucedownunder2 Guru  Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
This may interest those with mig welders and the like.. I see recently Bunnings have added to their gas range (that is, welding gas) . Telephoned them and they said they have "shielding gas" and Argon gas now in their returnable refill gas cylinder range . $99 for the gas and $200 for the once only deposit --Me, i would use a cylinder "D' size every 5 or even more years , so thats very reasonable -considering ,you get your $200 deposit on the cylinder back whenever you decide . Not all bunnings have them ,so ring around.. also , I'm interested in "TIG" welding , could someone enlighten me as to what i need to buy for my Mig welder,, Bruce Bushboy |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5078 |
I might look into this Bruce, thanks for the heads up. When I bought my mig about 30 years ago the gas bottle rent was ridiculous. I think it was $70 a year, and a refill was only $30. Like you a D bottle would last a few years before I needed a refill, so I was paying several times the gas cost in rent. So I ended up converting my mig to gas-less, but the weld was never as good and flux core wire is more expensive. I would like to go back to gas. Regarding TIG, I remember a mate bought a add on box for his standard arc welder, the box added the HV component on top of the welders LV AC. Long time ago, dont remember much about it. Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
straight argon is used for light tig welding, argon helium mix for heavy welds. mig welding steel sheetmetal with an argon 95% co2 5% mix heavy welding with argon80% co2 16% mix plus a sniff of Oxygen mig welding stainless and aluminium, use your tig gas. I'm confused, no wait... maybe I'm not... |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
From what i am aware of is a Mig is no good for use as a Tig welder, but you can use an old stick welder with a Tig add on kit, or better still an inverter welder with a Tig add on kit, or even some plasmer cutters also allow for a Tig add on. Sometimes it just works |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
The whole welding process is entirely different. Mig uses a constant voltage dc supply. You set the voltage, and use the wire speed motor to control the current (and the heat input). Tig uses a constant current supply, where the heat input is adjusted by varying the current. Its similar in principle to stick (arc) welding, except you absolutely must use the correct shield gas, and the water cooled electrode in the welding tip is not itself consumed as with a stick welder. While there are now some fancy electronic welders that can do both MIG and TIG with appropriate hand torches fitted, one is constant voltage, the other is constant current. No sweat at all for electronics to switch from one mode to the other. But if you have an older traditional transformer type of welder, its not really possible or practical to convert one type to the other, although there are some crazy claims out there that it can be done. Burning holes in metal does not require any finesse. But to make really nice welds you need a really nice welder. Cheers, Tony. |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
the way I think about it is fairly simple current changes the filler rod melt rate voltage changes the arc length. so stick and tig are regarded as MANUAL welding where everything is controlled by hand, it is easiest to weld manually when the melt rate is constant therefore constant current (CC) is used MIG is regarded as semi autonomous because the wire feed rate is fixed, so in this case the arc length needs to be kept at a set length, therefore it works best as constant voltage. There was a time when mig welding first started when there were a lot of big engine driven CC welders out in the field. Companies like Lincoln sold a hybrid suitcase wirefeeder to tide companies over until they could afford a new CV power supply. If you open the case up on a Lincoln LN-25 wirefeeder there is a CV/CC switch tucked away inside. supposedly using the CC setting made the wirefeeder voltage sensing variable speed so it could be used with the older engine driven machines. I have used it a few times, it works OK with heavy wire and heaps of amps on straight forward flat jobs but fairly useless for out of position work and almost impossible to use for light welding. I'm confused, no wait... maybe I'm not... |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Many of us here, (including myself) are infrequent weekend hobby welders. Its difficult enough to with the correct equipment, but trying to cobble something together on the cheap is going to make it all so very much more difficult. I have a 300Amp three phase transformer MIG which does quite well with gas, but is pretty messy with the gasless MIG wire which I currently use. Bunnings are on a real winner with this. I could never understand why welding gas costs two to three times as much in Australia as in any other part of the world. Cheers, Tony. |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
I was down at the secondhand metal shop today ,looking around for purlins for mounting my solar panels . Caught up with a guy and told him about bunnings gas.. he presently pays around 400 dollars per year on cylinder rental and gas . He also say the ad by bunnings and will discontinue his BOC rental asap.. I bought my argon last week , photcopied the receipt for later. now have gas forever and no ongoing rental . Purlins for my solar ,,, I'm using what they call steel formed "tophat" section ,then maybe either bolt the panels on directly with rubber washers between the al frame nad the zinc steel or just install the al rails(fairly expensive) Bruce Bushboy |
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