Why doesn't my torch work?

[VaughnT]

Had the chance to acquire an o/a rig. I've got the torch, lines and bottles, but I can't get the torch to light.

I crack open the acetylene and get a greasy yellow/orange flame that I would expect. But, when I open the oxygen valve on the handle all I get is a loud pop and the whole thing goes away.

The valves on the tanks are just barely cracked open. The acetylene valve on the hand piece can be opened all the way and all you get is a greasy, smoky flame.

Try to add in the oxygen to get a cutting flame and it's "pop" and then it's all gone. It blows out the acetylene flame, too.

Any idea what the problem is? What issues am I looking for? It doesn't matter how little you open the oxygen on the handle; just breaking it a hair is enough to "pop" and lose all fire.

[John B]

You don't mention regulators or gauges. In the UK these are essential, don't know about over in the US.

Assuming all jets are clean, and torches in good working order valve wise, it would seem a pressure problem

What is the state of fullness of these bottles ? That may well affect the flame potential and profile.

It may well be the acetelyne is low, and the oxy much higher or full,

or if they were acquired used, a worn valve seat on the torch or pressure lever valve could be a contributory factor



Can you get a welding flame set up or are you just attempting cutting?

[Loneforge]

Acetylene regulator set 3-5 psi and Oxygen 30-50...Should get some lamp black from straight Acetylene but this should clear right up after oxygen is opened. Now add Oxygen till the flames are about 14 inch from the tip and you should be good! Be safe!
http://www.nhada.com/docs/Oxygen%20and%20Acetylene%20Gas%20Pressures.pdf

[Larry H]

try changing the tip, also if its a two piece torch the 0x valve must be open all the way before opening the "cut" valve....2-1 or 3-1 on the pressures

[Tommy Traylor]

Try opening the tank valves all the way.

[clinton]

Acetylene should be open only 1/4 to 1/2 turn, oxygen is a double seating valve and it should be opened all the way. You could have a bad valve on your torch body, or a bad seat on your tip. Try removing the tip and inspect the seat (the area that makes contact where it meets the torch body) it should be smooth with no gouges. Also try cleaning the tip with a tip cleaner

[Mainely,Bob]

The functioning settings are largely made with the regulators (high limits) and should be adjusted to an appropriate setting for the tip you are using.
There is far more to these rigs that just scanning a pamphlet or posting questions on the internet. These things can ruin your day and test you homeowner`s and life insurance policies. Go to the place you get your tanks from and ask when their next safety course is being taught. Keep the valves on both tanks tightly closed until AFTER you complete that course. Once you fully undrestand and can properly conduct a "leak down test" then you can think about proceeding with the things that follow it. Right now I`m betting you don`t know what this test is or does.
SAFETY FIRST!!!

[VolcanoForge]

Did you get the set used from someone or did you purchase the tanks from a gas company? Is it possible that you have a cylinder of argon, nitrogen, co2....in place of oxy? torches will generally still work even if your pressure is all wrong, tip is messed up, etc.

[Frosty]

Go to your local welding supply and ask their help! Most will be more than happy to evaluate your set and show you how to use it, they're just too dangerous to mess with without knowing anything about them. So far most of the advice isn't too bad but . . .

Oxy acet is an equal pressure torch system and that's NOT gauge pressure (gpsi) it refers to molar weight as I recall. The gauge equivalent being set the oxy to 2x the acet pressure, for instance 5psi acet gets 10psi oxy. You can get away with more than 2x oxy psi but it can lead to problems. For instance you're cutting some rusty/dirty or otherwise scrungy steel and to make up for it you have the oxy cranked to say 5x and a piece of grunge gets kicked up by a pop, say a little water under some scale and gets directed into the torch tip. At 5x the oxy if blocked can be driven against the acet psi into the handle and up the acet hose and if it ignites you're holding a very loud firecracker.

At 2x it'll simply put the torch out and you get to clean it. I can't count how many times I've had to clean a crud plugged tip and I've never even heard of a properly set torch doing more than a little backfire. A backfire is a way too low set torch having the flame back up into the tip or even handle, hence the term "Backfire".

Open the tank valves all the way but do NOT reef on them to open or close them, they're precision tools and will seal properly with only a little pressure, if they don't they need to be rebuilt or at least tuned up. Welding suppliers do this for very reasonable prices for safety's sake. Most torch valves in need of rebuilding are in that condition because too many folk believe if a little snug, is good a LOT, as tight as they can turn it, is better. Just finger TIP pressure is plenty, even your propane tank doesn't need more.

Anyway, seek someone at the welding supply to check your rig and show you how it works safely. Learning to use it is a matter of practice though a class is a good idea.

Frosty The Lucky.

[ciladog]

Frosty, I have to disagree with you on setting the pressures. That 2X the acetylene pressure only holds up for certain conditions in welding (depending on the tip size) and is way off for cutting.


Acetylene pressure is rarely set above 5 psi for both welding and cutting but oxygen can be set from under 10 psi to over 20 psi for welding.
The oxygen pressure is a function of the welding tip size.

The oxygen pressure for cutting can be from 20 psi to over 50 psi again depending on the cutting tip size.

The reason for much higher pressures is that a cutting torch has two parts to it, the pre-heat orifice and the cutting orifice. The larger the torch and thickness of the material you are cutting is what determines the oxygen pressure.

The cutting orifice blows oxygen (not flame) on the hot metal and causes it to oxidize and burn away.

Here is a simple chart for setting the pressures.
http://www.nhada.com...s Pressures.pdf

[D.M.T.Forge]

you got fire in the torch take the tip off clean it and make sure the nut is tight