I would not try that with acetylene.
I don't like taking acetylene past 2" thickness.
I would go to a 100 lb. propane tank with an acetylene regulator.
You will also want a 240 or greater oxygen bottle with a high flow
regulator, and 3/8" hoses or your torch will choke.
The victor 315 torch is fine, but buy a #8 propane tip for it.
Run the propane at 5 psi and your oxygen at 100-125 psi.
Your oxygen regulator will freeze up if it can't handle high flow rates.
If the output gauge on your oxygen regulator goes up to 200 psi then it
is rated at 100 psi max output. You might be able to rent a high flow
To light propane:
Crack the fuel gas valve
Crack the oxygen valve
Rest the torch tip against a piece of steel at a 45 degree angle and
use your spark lighter to ignite the mix.
Now increase your fuel and oxygen in stages until your fuel gas is
maxed out and the flames have pulled back to a short LOUD pale ring of
The main reason people have had bad experiences trying to use propane
is that they treat it like acetylene.
That won't work.
Also keep the tip about 3/4" from the steel for optimal cutting.
If the tip gets clogged in the center from a blow-back, then use a tip
cleaner, but if the flame jets get dirty remove the tip and separate
the core from the outer shell. Then wire brush it and reassemble.
In general propane tips will last about 4 times as long as acetylene
Propane and the other LP gasses are far better for cutting heavy steel
than acetylene because their hottest point is much further from the
The heat will carry further through the steel.
For an 8" shaft you will have to travel very slowly in the center to
make sure you get a clean cut, and massive amounts of molten steel will
be flowing out the bottom of the cut.
I once cut a 700 lb. anvil from 6" plate steel. It took 30 minutes and
drained an oxygen bottle. Mind you I was using a pattern cutter.
I have cut up to 10" steel with propane.
It is the most common gas used in scrap yards and big burning shops.
It would be best to practice on a hunk of scrap steel to get your
travel speed down.
I seen this and tried it for myself. Couldn't get it to work well for
cutting. You've got 22% O2 instead of 100% O2
propane over compressef air is a tiny fraction of the cost of
acetelene over oxygen.
All the "field scrappers" around here who break down large assemblies in-
situ use oxy-propane. TONS cheaper than oxy-acetylene, and cuts most
steel very effectively.
The big problem Ig has is trying to cut that long a kerf. With enough
gas velocity, he might get the kerf 2" deep across the width of that big
shaft, but he'll have to 'wedge cut" sections out in order to get the
torch close enough to cut near the middle.
Most any-sized torch could do that if it's only hot enough to start
cutting, AND you have the time and gas to do it.
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