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Thread: Recommend a "standard" O/A welding setup

  1. #11
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    DrMike, here is my view regarding tanks of gas after 60+ years if using them. I am a hobbyist user, but a serious one who spends a a good bit of time in my shop.

    Yes, tanks are relatively expensive. However when you consider the difference in cost of the Smith's "kit" and a MIG or TIG unit, the Smith's kit WITH TANKS are about the same or maybe less. If you go TIG or MIG in your purchase, you STILL have a tank to buy, so this will run you more then the Smith's. As a hobbyist welder, tanks of gas will last you years before having to refill them. I usually have to refill mine about very 15 years or so. And a refill is not all that expensive if you take the tank to the welding store, at least here in Atlanta, GA. Usually runs around $30. Argon and helium are more if used with MIG and TIG, but not all that more.

    And one more thing. Your tanks will not be refilled and given back to. You will take them in and swap it for a full tank. So I usually demand a pretty new tank on my "refill" just because they look nice in the shop. All tanks taken in on the swap will be pressure tested and re-certified before being refilled. The refilling is usually done not at the store, but at a large plant outside the city or town. I am sure you have occasionally seen trucks full of tanks out on the streets. These are delivering to or picking up from industrial users, or taking them to the facility for refilling.

    And still one more thing. Some of the best methods of learning welding today are the instructional videos available on YouTube. Be sure to tune in!!!
    Last edited by Planeman41; 08-24-2018 at 10:05 PM.

  2. #12
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    Quote Originally Posted by DrMike View Post
    Am aware of the 1/7 per hour rule with acetylene. Unfortunately have no idea of the impact on what I want to do.

    The small plumbers kit came with no tanks, was considering buying/renting B acetylene and 20 cu-ft O2 tanks to complete the kit.
    I don't think you'll be happy with a small set. I purchased a Victor setup and ended up getting a 145 Cubic Foot Acetylene Cylinder 125 Cubic Foot Oxygen Cylinder (about 4 foot tall). I would recommend you buy what ever brand torch you can get local service for. Otherwise you're stuck waiting on mail order if you need a tip.

    Check out the tips required for various thicknesses and the associated SCFH
    http://www.allalloy.com/wp-content/u...ing-Nozzle.pdf


    TIG has the advantage of being able to weld all metals with a single shield gas you just swap AC/DC and filler alloy. Many small inverter TIG welders
    can run on both 120 and 240 (with reduced output of course).

  3. #13
    Join Date
    May 2018
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    SE MI USA
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    Thank you... more to think about and consider.

    According to Victor (link thanks to Ohio Mike above), these are acetylene consumption rates when welding:
    #0 tip : 1/32"-5/64" thick : 3-5 psi : 2-4 cf/h
    #1 tip : 3/64"-3/32" thick : 3-5 psi : 3-6 cf/h
    #2 tip : 1/16"-1/8" thick : 3-5 psi : 5-10 cf/h

    The tanks that come with a lot of the portable kits (20-cf O2 and 10-cf (MC) acetylene, about 19-lb total for the two tanks), if used with a neutral flame (1.1 oxy/acetylene) for heating, soldering, brazing or welding (not cutting), will require two MC acetylene tank refills for each O2 tank refill. Figuring 5 cf/h as an average from the data above, this is about 4 total hours of actual burn time (being careful to watch the draw rate of acetylene, of course). According to their online price data this morning for my zip code, AirGas would charge about $86 to fill 2 MC acetylene tanks and one 20-cf O2 tank, for about $21.50/hr of burn time.

    Upgrading both tanks to the next size up (40-cf O2 and 40-cf (B) acetylene, about 50-lb for the two tanks), again used with a neutral flame and not cutting, they would empty about the same time. Again using 5 cf/h from above, this is about 8 total hours of burn time. AirGas says that I can fill these two tanks today for a total of $63, or about $7.88/hr of burn time.

    For comparison purposes, MAP gas sells today at HD for $9 for a 14-oz bottle.

    I would expect the cost/hr of O/A burn time to continue to drop significantly with larger cylinders. Today AirGas charges $31.90 to fill a 10-cf (MC) acetylene tank and only $7.49 more to fill a 40-cf (B) tank. Of course, the cost of the cylinder goes up quickly with size, as does the difficulty with transport, storing and wrestling them around.

    Am I way off base here, or is this a reasonable way to look at the ongoing costs of O/A welding in a home shop?
    Last edited by DrMike; 08-25-2018 at 06:29 PM. Reason: now correctly using cf/h

  4. #14
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    First its consumption in Cf/H not minute. A B tank is more of a match for a R Oxygen. A 80 cf tank of C25 cost me $140 or so full and refills are $40. I can MIG weld with gas of course about 4 hours with that. That is not welding sheet metal at your low consumption rates above, but 1/8 to 1/4 inch and at 20 cf/H or $10 per. As soon as you start welding with your OA setup the rate will climb. That is why today commercial shops may use OA for cutting or brazing but never welding.
    Retired - Journeyman Refrigeration Pipefitter - Master Electrician - Fine Line Automation CNC 4x4 Router

  5. #15
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    Quote Originally Posted by wmgeorge View Post
    First its consumption in Cf/H not minute.
    You are absolutely right, my bad. Now fixed.

    Quote Originally Posted by wmgeorge View Post
    A 80 cf tank of C25 cost me $140 or so full and refills are $40. I can MIG weld with gas of course about 4 hours with that. That is not welding sheet metal at your low consumption rates above, but 1/8 to 1/4 inch and at 20 cf/H or $10 per. As soon as you start welding with your OA setup the rate will climb. That is why today commercial shops may use OA for cutting or brazing but never welding.
    I am not a commercial shop. I will only occasionally weld, and I barely have adequate electrical service to run my G4000 lathe or G0704 mill.

    I'm only looking to add occasional welding capability to a small home shop that only exists for my pleasure and (usually bad) home repairs. It might not make any sense at all to do so. Perhaps I'll abandon this thought and simply continue to look at soldering or brazing when I can't see a convenient way to work around a joining issue with threads.
    Last edited by DrMike; 08-25-2018 at 06:31 PM. Reason: sppeling

  6. #16
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    Nov 2008
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    Quote Originally Posted by DrMike View Post

    I'm only looking to add occasional welding capability to a small home shop that only exists for my pleasure and (usually bad) home repairs. It might not make any sense at all to do so. Perhaps I'll abandon this thought and simply continue to look at soldering or brazing when I can't see a convenient way to work around a joining issue with threads.
    No need to drop the whole idea. Pick up any used Harris based kit on craigslist. You frequently get the whole kit for the cost of the tanks and gas **. Replace parts like hoses as needed. Then buy the Harris 19-6a handle at a welder supply and you are good to go.

    If I recall correctly, the gas used by a torch is dependent on what you are using it for (settings) and the nozzle you choose. My recollection is that a smaller handle used with the same sized orifice will use the same amount of gas.

    Dan

    ** The tanks and gas do not depreciate. A $120 tank is swapped when you get them filled. The gas is worth whatever the next fill will cost. If you pay $250 for a pair of $100 tanks and $100 of gas AND a welding outfit you are way ahead of the game.
    Last edited by danlb; 08-25-2018 at 09:45 PM.
    Measure twice. Cut once. Weld. Repeat.
    ( Welding solves many problems.)

  7. #17
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    Ditto, you can find OA on Craigslist, sometimes dirt cheap. Here is the kicker, if the tanks are due for Insp and testing that will be on your nickel when you go in to have refilled. Inverter welders operate very efficiently. You can get a MIG or even a stick welder that will do 150 amps or so running on 220 volts that draws 20 amps..
    Retired - Journeyman Refrigeration Pipefitter - Master Electrician - Fine Line Automation CNC 4x4 Router

  8. #18
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    Quote Originally Posted by wmgeorge View Post
    First its consumption in Cf/H not minute. A B tank is more of a match for a R Oxygen. A 80 cf tank of C25 cost me $140 or so full and refills are $40. I can MIG weld with gas of course about 4 hours with that. That is not welding sheet metal at your low consumption rates above, but 1/8 to 1/4 inch and at 20 cf/H or $10 per. As soon as you start welding with your OA setup the rate will climb. That is why today commercial shops may use OA for cutting or brazing but never welding.
    I believe the real reason you don't see O/A welding in a commercial application very often is the time factor. It is by nature a slow process, not so much an issue for the hobbyist but a killer for a fab or production setting. Electric welding whether sick or mig is so much faster and cost effective.
    Sure the gas adds to the cost but do you really want to pay a guy twenty to thirty dollars an hour on top of that. Labor becomes the chief factor in the viability of the process in commercial applications.

    These are issues the home shop guy needn't concern himself with so much. Time is not that much of an issue for small welding jobs and gas isn't either because whether electric or gas, an hour's worth of actual welding time is an awful lot of welding time. Most time when welding is pre-op or post-op.
    95% preparation and 5% operation. LOL

    However if as the OP mentions, there is very much 1/4" or 3/8" O/A welding to be done I'd have to reconsider my choice of processes for various reasons. Gas use and comfort level being chief among those.
    Home, down in the valley behind the Red Angus
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  9. #19
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    Plus a good gas O/A weld is a work of art, as TIG has become also.
    Retired - Journeyman Refrigeration Pipefitter - Master Electrician - Fine Line Automation CNC 4x4 Router

  10. #20
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    Jul 2014
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    Cumberland, Maine
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    Got a pickup truck? My local supplier wouldn't fill tanks when I brought them in in an SUV. I told them I'd be happy to carry them off their property on my shoulder, but no joy. Had to come back with the truck.

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