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  1. #1
    mtbr member
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    O/A Tank size reccomendations

    Hello,

    I've been lurking here and on other frame building related forums for a few years.

    I finally have a real house with a real basement a real garage where I can get into whatever sort of trouble I want!

    My plan is to start hand filing miters and fillet brazing joints out of thin-wall 1.125" and 1.25" OD 4130 tubing. I expect to piece together quite a few practice joints before moving on to any actual frame building. I'm in no hurry and want to get in plenty of solid practice.

    I've ordered tubing blocks from paragon, tubing is on the way. I have an old Harris torch, hoses and regulators and files that were handed down from my father. (I may upgrade to lighter duty kit once I get my hands dirty.) A big order of filler and flux from wade at cycledesign is waiting on my bench.

    The only thing holding me up right now are tanks.

    I've located a local welding supplier, but expect that he won't be in tune with the volume and ratios used for fillet brazing thin wall tubing.

    The supplier is far away and has inconvenient hours, so it'd be nice if I didn't have to visit very often.

    I was thinking 50 Cu feet of Oxygen and 30 Cu feet of acetylene might be a good place to start... Any thoughts on how long this may last a beginning builder? It doesn't need to last 7 years, but I'd also hope to get quite a few practice joints and frames from my first fill-up.

    Thanks!

  2. #2
    Harrumph
    Reputation: G-reg's Avatar
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    I bought and exchange the smaller tanks. It would be nice to get the next step up in size, but haven't made the jump. Probably a false sense of security, but I feel safer transporting the smaller ones in my wagon and storing them in my garage.
    Slowly slipping to retrogrouchyness

  3. #3
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    Any idea what the actual capacity of your "smaller" tanks are?

    How much use do you get between exchanges. Hours/joints/frames... Just looking for some level of comparison...

  4. #4
    Randomhead
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    I got the biggest they would sell me. 80 cu in oxy maybe? I initially bought the smaller size, but went through them a little too fast for my taste. The tanks aren't very big, I used to transport the big tanks in my parent's VW bug BITD.

  5. #5
    Harrumph
    Reputation: G-reg's Avatar
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    O2 is 20 cubic ft. and 10 cubic ft. for the acetylene. I can't give a good estimate of frames / fill up, I've never started a fresh build with topped off tanks and I always seem to find things other than frames to set on fire. You will of course run out of only one at a time and in the middle of a project... Cosmic spite or something.
    Slowly slipping to retrogrouchyness

  6. #6
    Nemophilist
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    Hey;

    If you buy two sets of the user owned size, and religiously refill the dead ones after you change, you'll never be caught short.
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  7. #7
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    I got 3 frames out of my 30cubic feet acetylene tank before a refill. I'd like a larger one, but I'm switching to tig so I'll probably stay put. I had a small Meco midget torch, so a larger one would take more probably even at 5cfm. I switched to a larger torch and nozzle size to get enough heat for a fork crown. your mileage may vary, just a ballpark figure for you.
    cheers
    andy walker

  8. #8
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    I have a 10cu/ft "MC" size acetylene tank and 20Cu/Ft O2. They will last for approximately 95% of a single frame project and then inevitably run out at the worst possible time. The unit cost per cubic foot is much cheaper for refilling the medium and larger size tanks.
    If I were setting upagain exclusivly for brazing, I would do a BBQ propane tank as fuel instead of aceylene. Either use with an O2 bottle or else surplus medical O2 concentrator for very-cheap long-term supply of brazing gas.

  9. #9
    Dad
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    Iím always worried about running out when the LWS is closed on a weekend, so I bought an LP tube and tips for my torch and can sub in the bbq tank if I run out of acetylene. Itís cheaper fuel and tanks can be exchanged 24/7 at gas stations, although I understand itís a little harder to use than acetylene.

    As far as cylinder size goes, mine are both around 55cf, I think. Even though itís slightly smaller, I found I exchange the fuel tank more often. Throw in welding or cutting, and thatís out the window, though.

    Ask your supplier about the cost to change sizes as you figure things out. Mine let me upgrade to the next larger size for the cost difference, but was not going to be so accommodating if I down-sized for some reason.

  10. #10
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    Just get the largest tanks you can easily transport/store. Tanks are kind of like fake boobs, lots of people think medium is ok just to regret not going bigger in the beginning.

  11. #11
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    Thanks everyone. I was afraid that big ol' tanks might have been more than I'd need for a years worth of messing around, but that doesn't seem to be the case.

    I'd read quite a bit about the Oxy/Propane set-ups. It seemed like it might have put me at a bit of a disadvantage while learning. Is this not the case?

    I figured it would be easier to find time-tested info on tip choice and general methods if I stuck with the more standard oxy/acetylene setup.

  12. #12
    Randomhead
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    I think oxy/propane is probably the way to go. With an oxygen concentrator. Doug Fattic has posted a lot about this recently. It's a little fussier.

    When you are learning, it's best to have experienced help, btw.

  13. #13
    builder of frames
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    Using a BBQ propane tank with an oxygen concentrator makes so much sense to me. Last fall I added that option to my framebuilding classes and I'm really glad I did. First of all that combination is much more economical in both initial and operating costs. In addition getting propane is way more convenient in store hours and transport than acetylene at a welding store. I bought a refurbished concentrator with a 3 year warranty for $350. They can be found for $200. They don't need a regulator so they save that expense. A 125 cubit foot oxygen tank from my welding supply store is $315. The 150 cu foot one is $350.

    I usually get through about a class and a half with 150 Cubit feet oxygen ($20 refill) and 80 acetylene ($35) bottles. That's with 3 students making not only a frame for themselves but also doing a number of practice joints as well as many teacher demonstrations. After 4 classes I'm only half way down on the $18 refill BBQ propane tank! Of course 1 of the 3 students was using acetylene (one class had 2).

    I find most students learn easier with propane. Its slightly lower temperature allows a bit more time to assess and react to what is going on than hotter acetylene. It is true that doing a fillet brazed joint with acetylene is easier for me. However in Ukraine where we fillet braze some frames I have no problem using propane with a standard torch and tip set up. Of course using a Victor J-28 or Uniweld 71 torch handle with a UN-J mixer with 2-TEN or 3-TEN tips work better. I can switch back and forth between the two without effort.

    And by the way if you really want to get good at fillet brazing you will learn from an experienced teacher. Just watching an expert is not the same thing. I've had a number of students come from a variety of other framebuilding classes and the quality of what they have learned has varied a lot.

  14. #14
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    Doug has laid down the mother load of advice in a thread over on VSalon.

    I put together my set-up from his advice over the last couple months.



    A reminder to be careful with your set-up. Yesterday a plumber's car exploded due to improper storage of his acetylene tank.


  15. #15
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    RE: Explosion

    I build during my lunch period as a break from my day job. My employer and the building owner do not want O/A on site, as I store a lot of various Dangerous Goods here. That is plain scary, random, but scary. I can see why the powers that be are only tolerant of my little MAPP bottle and torch.

    Eric
    If I don't make an attempt, how will I know if it will work?

  16. #16
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    Doug,

    Thanks for your recommendation here and all the knowledge you dropped on the velosalon thread. I will look into oxygen concentrators, as it does seem to be a better fit for me.

    Explosions are scary. I'd happily trade that risk for a grill tank and a little box that looks like Wall-E and pulls oxygen from the atmosphere.
    Last edited by Pritchett; 05-28-2013 at 09:30 AM.

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