There are few things more annoying than fighting with your tools. Having an oxy acetylene torch constantly popping and blowing out is beyond frustrating. So how can you troubleshoot this problem and get to work?
The reason that an oxyacetylene cutting torch will pop and go out is because of a problem with gas flow. Usually this is either an issue with flow settings, a leak or blockage.
In short, it could be a number of things. Let’s work through the possibilities and figure out how to fix your problem.
First though, let’s go over the terms to identify what that popping sound actually is.
What’s Happening When Your Torch Pops
There are a few different terms used to describe the popping sound you might be hearing. Here they are, from minor issues to major problems:
Backfiring
What’s happening is that the flame is entering into the nozzle with a really loud popping sound. The flame may go out entirely, or it may re-ignite.
Really, the flame isn’t traveling too far back in the line, so usually this one isn’t a major safety concern as much as it is an annoyance. Mostly this will just slow you down and frustrate you.
Sustained Backfiring
This one is a bit more of a problem. The flame is staying inside your torch for a bit longer, which could eventually escalate to more major problems.
Instead of just a loud pop, you’ll hear a pop followed by a hissing or whistling noise as the flame burns inside your torch. Turn off the gas immediately until the hissing sound goes away.
Flashback
This is a major problem. For this, the flame isn’t just going inside your torch – it’s also running back up the line and into the supply system.
This could translate into a disaster. At best, nothing will really happen. Or your hose might burst with the pressure from an internal explosion. Or your tank could blow up.
It can get serious really fast.
The best way to completely avoid this is to install flashback arrestors on both the regulator outlets and the torch inlets. That way nothing will explode if you have a leak in your hose, too.
Backflow
This one is also serious.
Basically what’s happening for this is the high pressure gas (oxygen) is pushing back the low pressure gas (acetylene) and mixing in the hose. This is really volatile.
If you install those arrestors then this risk will be pretty well eliminated. As long as you take care of your equipment, anyway.
Ok, so aside from making sure that you have arrestors installed to ensure that you won’t blow up, let’s look at some other ways of troubleshooting this popping issue:
Dirty Nozzle
This is the easiest one to fix, so we might as well start here. Sorta like the “is your computer turned on” type of remedy.
So basically what happens here is that dirt will get in the nozzle and restrict the flow of oxygen and acetylene. When this isn’t mixing properly, there will be a really loud popping noise, and the flame might go out.
Just take a look at your tip. Is it black and nasty? Is there anything in the hole where the gas comes out?
Get a brass wire brush and clean it off. You should definitely have a tip cleaner in your tool kit (or pocket) when you’re working with a torch.
I’ve seen guys jam pieces of steel wire in there to clean it out. If you get a proper nozzle cleaner, though, you’ll be less likely to damage it.
Improper Flow Settings
Another common reason for this is due it improper flow settings.
Whenever you buy a new tip, it will have a little booklet with the operating instructions. This will include the flow settings for that particular tip.
A #8 tip will be very different from a #1 tip.
How to Know Correct Flow Rates for your Nozzle
Here’s an example of the rates for Victor nozzles. Use the chart to find your nozzle size, then adjust your regulator accordingly. If you have a different brand of torch, then just do a Google search to see if you can find that particular chart.
Also keep in mind that these values are for a set size and length of hose. If you have a particularly long hose, you may need to slightly increase your pressures.
Whenever I’m setting the flow rates, I start off in the middle of the range. Usually that will be pretty near bang on where you need to be but you can always fine-tune as you go.
Too Close to Work
If the torch is popping while you’re cutting, it may be because you’re holding the tip too close to the work and you’re restricting the gas flow. Just back up the torch and see if the problem persists.
Improper Lighting Procedure
If the popping is happening during or a moment after lighting, it might be because you’re lighting it too soon and with too little acetylene pressure.
If this is your problem, then it’s pretty easy to fix: Just use the proper lighting procedure.
Here are the steps:
Pre-Ignition Setup
- Back out the regulator pressure adjustment screws.
- Close the torch valves.
- Open the cylinder valves.
- Set the regulator pressure adjustment screws to the correct pressure for the tip you’re using.
- Open and close the torch valves individually to make sure that the correct pressure is holding and fine tune if needed.
- On a cutting torch, depress the lever and adjust if necessary
Lighting Procedure
- Purge both lines individually.
- Open the acetylene torch valve half a turn.
- Light the torch with a flint striker. Don’t use a lighter. It hurts when you miss.
- Increase the gas flow until there is no smoke and the flame leaves the tip of the torch.
- Decrease the flow until the flame returns to the tip of the torch.
- Open the oxygen valve and adjust it until you have a neutral flame.
- Depress the lever and fine-tune as needed.
If you follow those steps, then you’ll be drastically reducing the chance of problems with gas flow, and it’ll be really unlikely that you’ll have any popping if your equipment is in good shape.Make sure that you’re using a spark lighter. Burnt hands aren’t fun.
Leakage
One other way that you might be getting popping sounds is if there’s a leak.
If your nozzle isn’t seated properly, it could be letting air in.
Unscrew your nozzle and clean it well. When you’re installing it, spin it back and forth in the collet to make sure it’s seating properly.
How to Check for Leaks
If you’re not sure whether there’s a leak or not, use some soapy water to test it. Open up the oxygen and cover the tip with your finger. See if any bubbles come out.
Do the soap water test along the entire line, including the hose, regulator and cylinder connections.
A really common place for leaks is around the O-rings. Try cleaning and re-seating them, and look for cracks, wear and damage.
Overheated Nozzle
If the popping is only happening after you’ve been using the torch for a while, like maybe after half an hour or so, it might be because the nozzle is getting too hot.
What’s happening here is the heat is making the nozzle hole grow so it’s not restricting the gas flow like it’s supposed to. It’s similar in principle to having too low of pressure.
Here’s the easiest way to deal with this:
Turn off the torch with the torch valves. When the flame is out, open up the oxygen valve. Then dunk the nozzle in water. This will instantly cool it down, and water won’t go inside your torch.
Get a New Nozzle
Sometimes there’s nothing that you’re doing wrong. Equipment is exposed to wear and tear, and your nozzles are no exception.
Usually if your nozzles are worn out and tired, the hole at the tip isn’t nice, clean and round anymore. Or maybe the torch was dropped and now it’s deformed.
If it’s showing signs of wear and tear, it might be time to replace your nozzle.
Alright, there you have it. This should solve any likely problems that are giving you popping.
Have any other tips, or different ways of solving the problem? Share it in the comments.