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  • loose nut
    replied
    You do know that this thread finished 5 years ago don't you.

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  • Tilaran
    replied
    Originally posted by lazlo View Post
    We had a long thread about DIY CO2 generation (for welding) several months back.

    Straight CO2 gives a lousy arc compared with C25. It's hot, fiery arc that creates a ton of spatter. Straight C02 also oxidizes a lot more than C25, so most welding texts warn against using it on aluminum or stainless steel.

    I've used straight C02 on structural steel, and it was miserable. It penetrates like crazy though! Never tried it on aluminum.
    Stick with machining. You have no business MIG welding.

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  • aboard_epsilon
    replied
    I can't see the sense either in spending hours trawling the net or burning fuel and wasting time if it is urgent in the car just to save a couple of $ when it is available locally just for a few minutes trip - or even to have it delivered.
    delivered ..hmmm

    in the UK you pick it up from the the dealer ..and BOC tags another delivery charge (fixed charge) on top of the gas price ..

    what you got for one bottle IN THE UK IS is :-

    BOC argoshield light size Y... 4.8 cubic metres

    1 bottle

    YEARLY RENTAL; £81.,70

    the gas in it ..

    34.85 plus £5.23 vat .. = £40.08
    environmental energy surcharge £0.45
    fixed charges on it £11.35 plus £1.70 vat =£13.05
    equals £55.88 for the gas in the bottle

    so YEARLY RENTAL; £81.,70 plus £55.88 for the gas in one bottle

    1 bottle costs me £137 or $220 a year ..

    you seam to have more time than me Evan ..glad you're on the case

    all the best.markj

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  • oldtiffie
    replied
    BOC pdf file - sheilding gases

    Read from page 57 onward for shielding gas recommendations in this BOC (AU = OZ) pdf file.

    https://boc.com.au/boc_sp/au/downloa...S03-IndGas.pdf

    I will hunt out and post some other stuff shortly as regards MIG weld shielding gases and will
    post them later.

    Leave a comment:


  • oldtiffie
    replied
    No wukkin' furries

    I can not care less about "rip-offs" as me upsetting either myself or anyone else needlessly over something I either can't or won't do anything about is - in my opinion - an exercise in futility and stupidity on my part.

    Its either what I want for what I am prepared to pay on the day - or not. If it is a $10 item and I want it at that price. I buy it - couple of $ either way is of no concern. If was it "upped" to $100 and its essential that I have it - then I pay for it and use it. Sometimes that $100 was a good buy as there have been occasions which warranted paying $200 or more - with possibly more to come.

    I can't see the sense either in spending hours trawling the net or burning fuel and wasting time if it is urgent in the car just to save a couple of $ when it is available locally just for a few minutes trip - or even to have it delivered.

    It depends entirely on the circumstances and my judgment at the time.

    After I've bought it, its in the past and nothing will change it. I just - if needed - shrug my shoulders and move on.

    I just cannot see the sense in worrying needlessly.

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  • Evan
    replied
    75/25 is Argon/CO2. The price of Argon and CO2 is a complete rip off. Argon is a side product from liquefying air to obtain oxygen and it isn't exactly rare either. Every cubic metre of atmosphere contains a litre of argon gas. We all know how easy CO2 is to obtain, in fact it is usually made as a by product of producing acetylene from natural gas. Unlike acetylene neither argon or CO2 are toxic, explosive, or difficult to transport. The only hazard involved at all is gas under pressure and there is no local ecological consequence from a release of either in common circumstances. The training to handle the products for sale is minimal, I have had it.

    Those two gases in particular undoubtedly reap by far the highest profit margin of any of the industrial compressed gases with the possible exception of nitrogen. I would expect that the profit margin from production to retail sale is on the order of 2000 percent or more. Keep in mind that these gases are by products of the production of other gases and when in excess are simply vented. Because of this it is unlikely that plant amortization is applied to the cost of production.

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  • oldtiffie
    replied
    Littlies and biggies

    There would not be much that is more expensive in terms of cu.ft/$ than those small bottles, but in terms of convenience - small jobs and/or small spaces etc. and no need to fill and buy larger bottles - there isn't much better.

    You should seriously consider a "real (good)" regulator for them - not all that expensive instead of the standard "fixed" (so-called) regulator.

    The question - more often than not - is more why you should buy them rather than why you should not.

    There are some very good plusses and minuses either way depending upon your circumstances.

    But if you use a fair bit of gas in your shop, those smaller bottle prices will very soon make you realise that the "expensive" gas that everybody seems to be bitching about is not so expensive after all.

    I have only see argon and CO/CO2. I can't recall seeing the best all-round gas for steel - 75/25.

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  • Guest's Avatar
    Guest replied
    Originally posted by dp
    I was at the local HF store yesterday and noticed they have 20 cu ft argon and CO/2 bottles. They seem quite small - is that a good way to go? Seems very limiting, but I've never tried gas with my MIG. They were certainly cheap - I assume they are empty when purchased.

    Those are really quite small. You'd be changing them frequently.
    Last edited by gnm109; 07-07-2009, 08:58 PM.

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  • Willy
    replied
    At an approximate concentration of 33.5%, would battery acid be suitable?

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  • Evan
    replied
    That had occurred to me but the problem is the availability of H2SO4. I can only buy it in 25 litre bags for battery filling. I have some on hand since I use it for anodizing so I might give it a try.

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  • Duffy
    replied
    CO2 Generator

    Originally posted by Evan
    Does anybody have plans for a CO2 generator that uses either propane or natural gas to generate mig shielding gas? A quick look online shows they are extremely popular for growing indoor crops. Not what I want or need.
    Not using combustion for generation, but have you thought of chemical genration? Sulfuric acid on common limestone will certainly work. If you use common garden limestone, which incidentally is rated as high-chemical, (96% CaCO3 or better,) with 66* sulfuric acid, by my calculations, you will generate 2000 liters of CO2 for about $13.00. I pay about $10.00 for a 4 liter jug of acid, and garden limestone is only about $3.00/bag. The trick is to search some chemical history for plans for a Kipp generator. Build it to withstand a bit of pressure, and it will give CO2 at pressure, on demand. When not needed, the generator will just sit there waiting. Further, if you can make it work on the concentrated acid, the gas will be virtually dry. These things USED to be fairly common for any gas that could be generated by adding a liquid to a solid; hydrogen, carbon dioxide, acetylene, chlorine. They have just been forgotten. duffy

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  • Jim Shaper
    replied
    All the little MIG welders have the ability to reverse polarity, as Evan says, you need to for FC wire. The fluxcore wirefeed welders (which lack the gas valve, and sometimes the whip provisions for gas) have no need to reverse polarity so they often lack the option.

    Not all 230v machines offer the inductance control. I've never seen a 120v one that did.

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  • lazlo
    replied
    Originally posted by oldtiffie
    I agree that on the face of it, those small MIG bottles are a PITA and expensive and all too often have a fixed-rate regulator (of sorts).

    But for some-one up a ladder or in a roof/small space etc. and who has only domestic-type and/or large volt-drop long lead single-phase low amp power supplies - they are great.
    Right, they're often marketed as "HVAC" or "plumbing" kits, although I would imagine most air conditioning guys are doing brazing or soldering, and not welding.

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  • Evan
    replied
    Flux core uses opposite polarity of gas shielded so changing polarity is a given on all the machines.

    The important part of the inert gas arc welding process is not so much the shielding but the way the gas ionizes and forms an arc. Each gas is different and the noble gases are particularly effective in that respect since they are a singular species of atoms and don't take part in the reaction. I wonder what welding with Xenon would be like? Extremely bright I would think.

    I have some other ideas still including the possibility of applying something to the metal in advance that will evolve gas as it is heated. Calcium carbonate is a prime candidate.

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  • oldtiffie
    replied
    Home-made welding gas

    Thanks Jim.

    As you say - horses for courses. There is no way I'd get my "gun" under a car etc. That is where those better smaller machines perform their magic - in the right hands. Thin "out of position" welding is as hard as it gets - for me anyway. "In position" is OK as I usually "hit and miss" (weld - skip - weld and then go back again etc.) if needs be.

    I didn't mention changing polarity or inductance as I was not sure that the smaller machines have it.

    But I am quite looking forward to the "home-made" CO/CO2 welding gas process project leads.

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