How to cut with a Bernzomatic oxy torch

Hi. I have a Bernzomatic torch that takes two disposable tanks, one
oxygen tank, and one propane or MAPP tank. This torch is advertised
as being able to cut steel, but the link for "CUTTING" on the
Bernzomatic website is down. On a standard oxyacetylene cutting
torch, you preheat, then hit the lever when the steel is hot to start
cutting. But, this little Bernzomatic torch does not have a lever.
Do you just heat with an oxidizing flame, then shut off the fuel gas
when things get hot? Does this create a potentially dangerous "pop"?
Has anyone tried cutting with one of these little things? Aside
from the oxygen consumption, did it work OK?
Reply to
Eric Chang
Loading thread data ...
If it's thicker than a tin can, and you want anything resembling a clean cut, forget it. The thing is useless enough as a brazing torch, almost hopeless for welding, and a REAL joke for cutting.
Reply to
It's convenient for silver soldering various components of model steam engines (crankshafts, boilers, etc.), but that's about it.
I bought one on a Friday night when I was changing the front shocks on my new (to me) 1990 Miata, and ran out of oxygen while cutting out the lower shock bolt. The local gas shops wouldn't be open 'til Monday and I couldn't wait. Two "tanks" of oxygen (the one that came with it and another at $12.99!) later I had managed to at least anneal the 12 m/m 10.9 (180K psi) bolt enough that a bi-metal Sawzall blade and some well placed 5 lb. hammer driven chisel blows could finish the cut.
Save your money and buy a real oxy/acetylene rig if you want to cut steel.
Reply to
Cliff Knight
Those torches don't have enough gas to do much, but........There is a way. Heat a spot to white heat, and turn off the fuel. The Oxygen will do the cutting, briefly.
Steve R.
Reply to
The heat available with that thing is very minimal and you can cut fine stuff with it but heavier stuff still needs bigger torches that run O/A which makes a bit more heat.
-- Bob May Losing weight is easy! If you ever want to lose weight, eat and drink less. Works every time it is tried!
Reply to
Bob May
Hi Cliff. Thanks for the real world info. I suspected that this torch is not really a serious candidate for cutting. I noticed that the nozzle is about 0.042 (42 thousandths) in diameter, which is between a 0 and 1 tip. These tips, on a real oxy-acetylene cutting torch require something like 30 cu ft of oxygen per hour. This would make it difficult to run the torch for more than a few minutes (the pressure is lower, and there is some fuel gas competing for the flow path through the nozzle). I have access to big oxygen tanks, but not big acetylene tanks, so oxygen is not a problem. But, if the little torch only anneals the bolt, it will be little use for cutting.
Thanks again, Eric
Reply to
Eric Chang
Hi Steve. Thanks for the info. This makes a lot of sense, since if the oxygen pressure can be boosted to what a cutting torch normally uses, the Bernzomatic nozzle diameter being about 0.042" is about the same as a 0 or 1 cutting tip. Therefore, if the fuel is off, and it is the oxygen that does the cutting, this should be able to cut 1/2" - 1" thick steel. I have a large oxygen tank, but no companion large acetylene tank. Anyway, I was thinking of starting the cut with propane.
Guess I just have to try it. I was afraid of getting a "pop" when I turned off the fuel gas. A pop with molten steel around is potentially dangerous, but with an oxidizing flame, maybe there will not be too much molten metal around.
Thanks again, Eric
Reply to
Eric Chang

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.