Turbo torch & 1/7 rule

[jrschatz]

Hi All -


I have a question for everyone out there using acetylene torches. I have had a B-tank for quite a while but was recently talking to a welding buddy of mine about his oxy-acetylene tanks. He mentioned the 1/7 (or in some cases 1/10) rule for flow rate of acetylene. That is, that you cannot use a flow rate of more than 1/7 of the CF of your tank per hour--- in the case of a 40CF b-tank, that would mean you cannot use a Turbo Torch tip above A-5. I have seen guys for years use much larger tips including the A-32 on their B-tank. There is even a video from a TurboTorch rep about using an A-32 on a B-tank.... I really cannot find any information out there as to whether this practice is dangerous or not... and if it is, how in the world can you carry around a 200+CF acetylene tank to a job when it requires an A-32? Any experience of knowledge is appreciated on this!

 

[Sylvan]

I have brazed 4" copper with a small torch as long as you heat the tubing and then the fitting playing the flames feather for Max heat and let capillary attraction (action) do its job For 6" we used two B tanks with another guy heating the tubing and fitting from the opposite side

A lot of people tend to overheat the piping. The only times I have to use Oxy/acetylene was brazing TP copper (Flagg flow fittings )

 

[Sponsor]

 

[jrschatz]

thanks for the input Sylvan -- I should clarify though, I'm not asking about getting sufficient heat to a fitting but rather whether it is dangerous to operate an A-32 turbo torch tip using a B-tank. If you read on welding sites about the 1/7 rule, it seems that it wouldn't be....but again, I've see guys dozens of times use this set-up on copper DWV and lead/CI joints.

 

[Jeff H Young]

Perhaps 1/7 rule is with ox /ac ? but Ive only used a 32 on a b tank. check with victor I suppose. If your using the big tip and have ox /ac Id have no use for an a 32 . just go with a rosebud . I havent seen turbo torches used on big tanks

 

[Fitter30]

B tank 33 cu ft volume. A32 tip flows 3.6 scfh. 1/7 rule so that liquid acetylene doesn't start flowing..
https://wagnerweldingsupply.com/17th-acetylene-rule-what-you-need-know
Agree with others rosebud can do so more with them.

 

[Sylvan]

If you need to braze 6" copper then

thanks for the input Sylvan -- I should clarify though, I'm not asking about getting sufficient heat to a fitting but rather whether it is dangerous to operate an A-32 turbo torch tip using a B-tank. If you read on welding sites about the 1/7 rule, it seems that it wouldn't be....but again, I've see guys dozens of times use this set-up on copper DWV and lead/CI joints.

Yes it is dangerous as some people use over 15 PSI acetylene for cutting and acetone will start flowing ALSO all acetylene tanks should be upright

https://www.amazon.com/Acetylene-We...4#:~:text=B Steel Acetylene Cylinder - 40,ft.

 

[Terry]

I haven't used a B-tank in a while. I'm mainly using a kit like this.

 

[Skoronesa]

If you need to braze 6" copper then
Yes it is dangerous as some people use over 15 PSI acetylene for cutting and acetone will start flowing ALSO all acetylene tanks should be upright

The real danger is even worse, when you get liquid acetylene going into the hose it can bring the acetone with it. Acetylene is mixed with acetone to make it less volatile. Without sufficient acetone in the cylinder the "agassman" material in the tank alone may not be enough to keep the acetylene "calm". Forget your hoses exploding, the tank might explode.

I've seen guys use huge tips on an mc tank, and it CAN work fine if the tank is warm, at least until it cools. Our guys all have B tanks and generally don't go over a 20mm/3/4" tip. Now a days with XLC press we don't solder much if anything above 1-1/4". The 1/10 rule is generally what guys follow in colder climates like canadia while most americans hear of the 1/7 rule.

Doing service I haven't used acetylene in years. On the rare occasions I need more heat, usually from water, I setup my second torch. We use the yellow 1lb "Map/pro" propylene/propane gas mix. I'm not dragging in a B tank or wasting space on the van for something I don't need. We don't braze copper underground usually either, we use corporation/mcdonald fittings or sometimes flare it.

 

[Jeff H Young]

My go to for most work is the Terry Love kit minus the fancy tip. But I much prefer the b tank especially on jobs where fighting water. 1 inch and up if I got a lot of soldering or If I'm going to just be doing copper on single family homes its just a hassle dragging a b tank around but I way prefer using a b tank set up but have fallen away from it since I'm doing more repair and remodel lately. just used my b tank yesterday with a 14 tip for some brazing

 

[Fitter30]

My go to for most work is the Terry Love kit minus the fancy tip. But I much prefer the b tank especialy on jobs where fighting water. 1 inch and up if I got a lot of soldering or If Im going to just be doing copper on single family homes its just a hassel dragging a b tank around but I way prefer using a b tank set up but have fallen away from it since Im doing more repair and remodel lately. just used my b tank yesterday with a 14 tip for some brazing

When working for a large mechanical contractor tools are not a problem. Freeze kits used them at least once a month. Stocked liquid co2 in are warehouse and phone numbers for everybody.