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08-23-2004, 12:54 PM #1
I recently purchased a set of torches and now I need to see about getting some bottles. I plan on using the torches mainly for cutting but also heating for bending purposes from time to time. What size bottles would you reccomend? I want to own the tanks, I really don't want to get into the rental game; I wouldn't be able to justify the cost. Thanks for your input. Take care.
08-23-2004, 03:32 PM #2
If you'll mainly be doing cutting you want to buy the largest oxygen bottle they have for sale. In this area the largest customer owned oxygen is a 160. An 80 acetylene will work fine with that. This is something that varies from place to place, but around here there is a set price for a pair of bottles, and it doesn't vary according to size. We had some 90 oxygens and when the supply house added 160's as a customer owned we checked into swapping in our 90's for 160's. They made the swap at no charge.
08-23-2004, 07:17 PM #3
Around here the largest we can own are: 80 cu. ft. Oxy and 40 cu. ft. acetylene ( plumber's "B" tank) I do little or no cutting and mainly use for bending/heating and welding up exhaust systems, etc. and fill one to three times per year depending how energetic I feel (hobby work) My cost in 1982 was Oxy tank $223 / fill $10.75 and $108 Acet / fill $17.60 Today it costs about $60 to fill both ( all CDN funds ) A caring gas supplier will give you a newer Oxy. tank in exchange as they need to be re-certified every ten years here, at your expense. Think I am way ahead of the rental game as my owner cost for the tanks for 2004 is something like fifteen bucks.
08-23-2004, 11:28 PM #4
A 251 cubic foot oxygen, and a 145 aceytlene are the largest I have been able to find as customer owned tanks. The 145 is the same size as a lot of lease tanks, but has a specific serial number prefix to designate customer owned. The 251 also has a particular serial prefix, but mine says Customer owned on the ring.
David from jax
08-24-2004, 07:04 AM #5
I like 200cft Oxy and 100cft Acet cylinder size. That will do most of general shop work for a long time and make them fairly easy to handle.
Any smaller and it's easy to over draw the acetylene cylinder while heating. You can also get a LP/air preheater and use that too preheat larger pieces then finish heating with Oxy/Acet. A used BB-Q grill or deep fryer base works well. Saves alittle money since acetylene cost so much.
08-24-2004, 12:10 PM #6
Around here they charge a flat HAZMAT fee per transaction when bottles are exchanged/refilled; & my time per exchange is the same, which made the bigger ones more cost effective.
08-25-2004, 10:38 AM #7
Thanks to everyone for responding. I'll make a trip to the local welding outfitter soon. Thanks again. Take care.
08-25-2004, 09:24 PM #8<JeffG> Guest
T_Bone's comment about overdrawing the acetylene cylinder needs elaboration. I'm also a newbie to gas welding, but from what I've read, the bottle size determines the max gas flow rate. Small bottles may limit the allowable torch tips, cutting or heating capacity. Any of the experts want to expand on this?
08-25-2004, 10:19 PM #9
The rule of thumb is you should use acetylene at a rate that is not greater than 15% of the tank in an hour. So if you use acetylene at a constant rate, you should use a tip small enough to get 7 hours use out of the tank.
If you really need to crank a bigger flame for a moment, that is not a problem. Sustained use at higher flow rates is the real issue.
In the tank Acetylene is stored disolved in acetone. As you draw acetylene gas out of the top of the tank, more aceylene comes out of the acetone and goes down the line to the torch. At some point you'll consume actylene faster than it can be replaced.
At that point, you start to draw acetone into the torch. (one of the reasons never to use an acy tank on it's side) Acetone in the torch will cause sputtering and some welding difficulties, but you have just burnt up some acetone. Acetone holds acetylene - so by losing acetone, the tank will now hold less acetylene.
As to tank size, I recommend the largest tanks that you can move around yourself. There was a welding shop around here, big fire, lives saved because the first thing they did was get the acy tanks out of the building!