PDA

View Full Version : Oxy-acetylene question...



Eric DeSilva
11-13-2009, 12:49 PM
...not really a power tool, but thought I'd see if anyone knows the answer. I've often heard a rule of thumb that a flow rate of less than 1/7 the tank volume per hour is required for acetylene if you don't want something bad--like the tank exploding--to happen.

Anyone have any idea what that 1/7th would be in terms of PSI at the torch for a B-tank?

John Coloccia
11-13-2009, 12:54 PM
...not really a power tool, but thought I'd see if anyone knows the answer. I've often heard a rule of thumb that a flow rate of less than 1/7 the tank volume per hour is required for acetylene if you don't want something bad--like the tank exploding--to happen.

Anyone have any idea what that 1/7th would be in terms of PSI at the torch for a B-tank?

Your torch tip will have a chart that gives you the flow rates. For example, it might me spec'd at 5-10 PSI for 15-20 SCFM, or something like that. So large tips will have high flow rates and small tips will have low flow rates (the extreme case be a completely blocked tip and 0 flow rate regardless of pressure!).

Eric DeSilva
11-13-2009, 1:13 PM
Your torch tip will have a chart that gives you the flow rates. For example, it might me spec'd at 5-10 PSI for 15-20 SCFM, or something like that. So large tips will have high flow rates and small tips will have low flow rates (the extreme case be a completely blocked tip and 0 flow rate regardless of pressure!).

Thanks--d'oh. That should have been obvious. I actually found this handy set of charts: http://www.hoopersupply.com/tipchart.html

If a B Tank is 40 cuft, 1/7 of that is a little over 5 cuft, so I shouldn't exceed 5 SCFH. I think what I'm seeing is that I can't exceed 5 psi with a #1 victor tip using a B tank. And, I can't use even the smallest heating tip at all. Bummer. I need to heat up and shape (hammer & anvil) the end of a 1/2" diameter mild steel rod. Wonder how effective I'm going to be with a #0 tip welding tip and only 5 psi.

Eric DeSilva
11-13-2009, 1:24 PM
Am I doing my math right? I started thinking about MC tanks--10 cuft--and it doesn't even seem like you could run a #000 victor torch off it. When I had my MC tank, I just used with a Harris Littletorch for silversmithing, but other than that... I take it MC is useless for any real welding?

harry strasil
11-13-2009, 3:16 PM
yeah, MC stands for Motor Cycle, they were used to power the lights in the old days.

ACet tanks take 7 hours to fill, if you exceed the 1/7th per hour rate by use, it pulls the acetone that the acetylene gas is dissolved in out and it ruins ur gauges etc. B is usually refered to as a Prestolite tank for plumbers use in soft soldering copper tubing. its basically just a bigger toy than the MC.

harry strasil
11-13-2009, 3:25 PM
go to ur Ace Hdwe or other hdw store and get a Model JTH-7 Bernzomatic torch and a couple of yellow Bernzomatic yellow gas cylinders and a couple of fire brick, set one brick on top of the other and lay the 1/2 rod in the V of the bricks and heat away, it will take a little longer than oxy/acet, but it will get it hot enough to work. If you are going to do a lot of forging, make a can forge, by lining a coffee can with kawool and insert the berzomatic torch in the side thru a hole.

harry strasil
11-13-2009, 3:27 PM
http://www.paragoncode.com/shop/micro_forge/

Robert Snowden
11-14-2009, 8:20 AM
You can use propane with your acetylene reglator and heat anything that you want to.It take's a little longer to get it hot. It is also safer than acetylene.Robert

Eric DeSilva
11-16-2009, 11:26 AM
Thanks for all the help. Turns out a #0 victor tip at 3 psi on acetylene and oxygen is quite sufficient to heat up 1/2" steel rod for blacksmithing, and will easily allow you to create a puddle for welding.

I've now determined, on the other hand, that blacksmithing with a torch is not so workable. You can heat the rod white hot, but then you need to turn off the torch, set it down safely, pick up your hammer, then you can hit the metal. Of course, by then, the metal is no long white hot. I suppose the answer is holding the torch in a fixed position with some kind of jig, but that leaves me awful nervous. A microforge might be the answer...

Eric DeSilva
11-16-2009, 11:27 AM
I dug around some more and the theory I'm seeing is that MC = "motor car" and B = "bus"...