40cf tanks for O/A welding?

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Hello, I'm extremely new to the welding world and want to make sure I have my bases covered so I don't blow myself up.A little while ago, I bought a 40cf oxygen tank and a 40cf acetylene tank (a B tank, I guess), for cutting up scraps to use with my amature blacksmithing.  I recently decided I can expand my projects by incorporating welding with my O/A instead of just cutting pieces for forging.After reading many random things for the last few hours, I learned that you apparently aren't supposed to use more than 1/7th of your acetylene's tank capacity over the course of an hour or you'll die (or something similar).  I have definitely used the majority of my acetylene tank's 40cf capacity in one hour in the past and haven't blown up yet, though.So, if the things I will be welding together are anywhere from 1/8" thick to probably as much as 1/2", it almost sounds like it isn't really possible with a B size tank.  Or if it is, I could only use like 6cf per hour, which with a smaller tip might go for a short while.Anyone have any input or advice?  I'm not really interested in TIG, MIG, or any other acronyms at this point due to already having everything for O/A.  Thanks in advance.
Reply:Here's a chart that lists SCFM's for various tip sizes for cutting, heating and welding. A 40cf cylinder is really too small for anything but light weight stuff. If you want to start doing 1/4" + you will want to look at getting a larger cylinder. It's probably not cost effective to manifold small cylinders like you do with bigger acet cylinders for very large tips. The cost of the parts would quickly exceed what it would cost to simply get a larger cylinder. Since you mention amateur blacksmithing, going to a larger cylinder is probably a good idea. If you ever want to use a rosebud for heating, even a 75 cf cylinder exceeds the withdrawl rate for the smallest rosebuds except on the lowest flow settings. A 40cf cylinder is just asking for trouble. http://www.hoopersupply.com/tipchart.htmlIf you just need to heat, cut or solder/braze, propane may be an option. You don't have the withdrawl rate issues with propane. You can't weld however with propane.My LWS will "upgrade" any of my cylinders when I exchange them for the difference in cost between the 2 cylinders plus gas. Example: they sell a "B" size 40 cf cylinder for around $75 and  the next size up (75cf) for about $110. If you wanted to upgrade to the 75 if would cost you $35 to get the larger cylinder plus the gas and you'd own the 75cf cylinder. The only other thing is that most rigs set up for "B" size cylinders don't match the CGA fittings on the larger cylinders. You would need to get the adapter that lets you hook up your acet reg to the CGA 510 valves on the 75 cf cylinder. You need the same adapter if you would want to hook up to a propane cylinder that you would to hook up to the 75cf cyl. Or you could always forge weld the 1/2" or hot rivet things together... .No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Thanks for the quick reply and the information.Yeah, lol, I played with forge-welding but not for sticking two big pieces together.  Didn't occur to me to rivet them though actually.  That sounds like an idea for me though, seeing if my supplier will take my 40cf + cash for a larger cylinder.  Maybe upgrading both the oxy and acet tanks since they like to drain disproportionately.  Thanks again.
Reply:There's a lot of ways to hold things together old fashioned blacksmith style. They also used to wrap a hot steel band around the cold pieces. Just like with rivets the bands shrink when they cool and tighten up. You can also spiral two pieces together some times and get them to hold if done right. Rivets, and bands often make a blacksmithing project "look" more traditional as well, even if they aren't functional.Even though you said aren't interested in other processes, I'd keep my eyes open for a nice used 220v transformer stick machine. You can often find these used cheap on CL for $50-150, sometimes even less. An AC/DC one would give you the most options, but a plain old AC unit will be just fine for what you would be doing.  Most of the older ones are pretty rugged and don't usually go "bad" in a home environment. They may be dirty, rusty etc, but your grand kids could probably still run them for years to come. Stick makes a nice complement to the home blacksmith. If you use a rod like 7014 or 7024, almost anyone can do a decent job for small projects on 1/4"- 1/2", where safety isn't an issue, with a bit of practice. Most homes have a 30 amp 220v dryer, so add an extension cord and you are good to go with medium sized rods.  You can weld up pieces and then "hide" the welds by forging them out. Lots simpler than hammer forging shorts together and gives you more options to work with on projects. Use the OA for thin stuff that is a PITA for stick, and use the stick machine for the thicker stuff.Be sure and post up picts of your projects. There's a lot of guys here who do all sorts of decorative metal work, both with the forge and by cold bending and welding. You'll find a ton of ideas and suggestions if you read and search a bit. I've got a folder full of picts of plant hangers, hanging basket holders, tiki torch stands, wine bottle racks, shelf brackets, coat hooks, candle stands and such I've seen done here, saved up for as soon as I get my forge set up as projects. I can't wait to get back to blacksmithing again.Several guys here are very good at OA welding and if you post up picts and your settings, they can probably help you learn. Same goes if you do choose to get a stick machine or mig and want to expand your arsenal. Good luck..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Oh, that isn't too bad then.  I guess I didn't realize they were that cheap.  So a small 220v arc welder would be adequate for  1/4" to 1/2" welds then?  Think I'll take a peak at CL to see what I can find.  Thanks again.
Reply:Stay away from the 110v units and  avoid some of the cheap HF and import stuff and chances are you are ok. The older 220v Lincoln AC225's, AC 180's and the AC/DC versions of the same machines, Miller Thunderbolts, Century arc welders will do what you want. Century made most of the old Montgomery Wards and Craftsman machines, as well as other older  "rebranded" store machines, so they are good choices as well. I think Century also built the Dayton machines as well. Century is now part of Lincoln. I just sold my old AC Craftsman machine that I bought used years ago to one of the members here ( Arcspark) for $50 and it's still going strong. It was one of the old "plug" style machines, but it's not all that different than the tapped Lincoln AC 225's you find in Depot new for way too much money.You can also find any number of larger "industrial" stick welders out there dirt cheap with the economy the way it is. The old  Dialarcs, Ideal arcs, as well as any number of Ltec, Essab, Hobarts machines etc that were used in heavy industry as long as they aren't 3 phase, are good choices. They usually run a bit more money, $300-700, but you can occasionally find some real deals if you know what to look out for and keep your eyes open. Some of the big tig machines are also cheap deals. They will stick weld as well as do tig and can be found usually between $500-800, but again you can occasionally find some real steals if the owner passed away and the family just wants to unload the monster in the garage.A 180 - 225 amp AC stick machine will do 1/2" steel if used properly. An AC/DC machine runs a bit smoother, but they usually cost a bit more, and for small projects, you don't really need one. On a 30 amp dryer outlet you can usually run most 3/32" rods without tripping the breaker. That will easily let you do 1/4" to maybe 3/8". If you want to do 1/2" you probably want to run 1/8" rods or bigger, and that's usually a bit much on only a 30 amp breaker. ( and NO, running the machine on a smaller breaker won't hurt anything, only limit your output) The machines are designed to draw about 50 amps 220v at max, so a dedicated 50 amp 220v line or a range outlet will let you run 1/8" or larger rods for heavier steel. If the use is purely decorative, like is most likely the case with forge projects, you can  probably get away with using smaller rods like 3/32" on thicker steel and doing multiple passes.If you don't use a craigslist aggregator like Crazedlist or Searchtempest, it's well worth doing so. Lets you search a wider area for deals. I usually type in "welder" and search the list manually to se if I can find any "hidden" items. Take a minute to add your location to your User CP at the top left so we have a general idea where you are located. Many of the guys here surf CL daily and they might see something worth passing on, or know of some good places local where you can get steel at good prices. ( if you are buying your materials at Depot/Lowes, you need to find a good steel supplier or scrap yard to save some big money) If you are serious and we know where you are roughly, several guys often will take a minute or two and type in your zip code or area name and do a quick browse of CL to help you spot some of the off name units that might be good deals.Last edited by DSW; 04-06-2012 at 07:37 PM..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:A concern I had with any welding equipment that uses electricity is that I sweat a LOT from my hands.  It is completely uncontrollable, unfortunately, and occurs regardless of the temperature of my surroundings.  So let's say I have lots of moisture on my body, is there an unsafe distance to be from the welder?I live a little south of Tucson, AZ, by the way.  Thanks.
Reply:Sweat will make you more susceptible to shocks, but having a dry set of gloves will limit this. You also can do some small things like making sure your ground clamp is always the other side of your body from the rod you are using. If you get between the two, there is a slight chance you might make a better path for the electric than the leads.A DC machine is a bit "safer" than an AC machine in damp conditions. We used to weld underwater with DC machines when I worked as a commercial diver. Can't get any wetter than being completely submerged in water in a set of coveralls and welding. The only rubber we were wearing was a set of rubber gloves as far as insulation for the electric. Again we always made sure the diver never got between the lead when welding.Get shocked a few times... Yes, been there done that, but it's not as bad as many think. It's not likely you'll fry yourself doing this. I stayed away from learning stick in Jr High because electricity scared me. Now I realize how safe it really is. I'd been shocked more times form outlets around the house than I have welding over the years.50 mile search for CL in Tucson, AZ..http://www.searchtempest.com/results...sk=&subcat=sssYou'll need to scroll down a bit to get to these...Looks like a nice Century AC machine is available for $80 listed as (Downtown) on the 2nd of this month. Says it needs a stinger, but his estimate of $40 is high unless it needs leads as well as the actual stinger. Migh be able to get him to go down lower since you can't test the machine and need to buy the stinger. On a budget, it's worth a call.There's also what looks to be a very nice Round top Lincoln Idealarc 250 listed on the 1st for $250.  $250 is a great price for an outstanding machine. The machine is AC/DC and you really can't ask for a better learning stick machine. Many schools use these to teach students stick. This is a machine you will never outgrow, and chances are you can get almost every penny you spend on it out again in 5 to 10 years if you wanted to sell it to upgrade. These machines are tanks and almost never go bad or break, and when they do, they are stupid simple to fix. I believe Lincoln still manufactures them with the flat top today. I bet it's still available since it's only listed as a "stick machine $250" If you are at all woried about getting shocked, buy this one over the AC only one above, not that it would make a huge difference in reality. If you want later, you can add a basic tig torch to this machine and do DC tig on a budget for a very reasonable price. Something to think about for the future.Last edited by DSW; 04-06-2012 at 08:16 PM..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan