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Propane cutting

Cut up some old steel for a friend yesterday.

Didn't find out until finished that I had not tightened the O2 nut down, and it was sucking air. What can I say?

Anyway, the blue flame points on the tip are totally different than acetylene, and when cranking on the propane, it's hard to see the flame and to get the gas on to the right level. I had it set at 4 and 20 with about a #1 tip.

I find it difficult to adjust the gas at first, and then to adjust the O2 to where I get even blue points on the tip when I press the plunger.

Can someone walk me through setting a propane torch right? Maybe drop down to 2 and 20 on the pressure? It was mostly thin stuff, but it cut some 1/2" stuff, although slowly.

Overall, in the first real test of this, I was satisfied.

Steve

Reply to
SteveB
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One thing for sure, with O/LP cutting you want the torch tip up a lot higher than with O/A cutting. Get the tip up at least half an inch. Here is a propane 2-part tip chart (Harris):

LP/Natural Gas Tip Chart

TIP PLATE OXYGEN Fuel Gas ORIFICE SIZE THICKNESS PSIG PSIG DRILL SIZE

000 1/8 20-25 3-5 #71 00 1/4 20-25 3-5 #67 0 3/8-1/2 25-35 3-5 #60 1 3/4 30-35 4-6 #56 2 1-1 1/2 35-45 4-9 #53 3 2-2 1/2 40-50 5-10 #50

These data are lifted from Ernie Leimkuhler's gas welding/cutting class notes.

Grant Erwin

Reply to
Grant Erwin

Set your LP pressure for 5 psi always no matter what size tip you are using.

Start with the gas just barely cracked open. Light it and add enough oxygen to bring the preheat flames back to the tip, then increase the LP, then increase the oxygen. Keep increasing the gasses in stages until the LP is maxed out, and turn the oxygen until the preheat flames are pulled back to a pale blue, loud flame.

The flame will be appear more oxidizing than an oxy-acetylene flame. This is normal.

The main difference between Acetylene and LP is where the majority of the heat is.

With acetylene the highest heat is at the tip of the inner cones. With LP the highest heat is further away, between 3/4" and 1-1/2" from the tip. This is why LP cuts heavy steel faster and cleaner than acetylene. There is more heat from the preheat flame further into the cut so the cut sustains better.

Reply to
Ernie Leimkuhler

I was in there, then, with the 4/20 mix on a 0 tip. Just had one loose hose. I'll get there. After you do ANYTHING for five or six hundred hours, you get the hang of it.

Steve

Reply to
SteveB

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