Author Topic: New to me cutting torch question  (Read 2653 times)

Offline Kenneth07ex

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New to me cutting torch question
« on: December 24, 2020, 06:52:56 PM »
Just bought a used cutting torch set. The regulators are Victor. And except for a tiny leak at the bottle coupling, the oxygen side performs as it should. My question is about the acetylene. As soon as I shut off the pressure at the tank, the acetylene guages drop to zero in less than two seconds. I never smell any gas, and it otherwise works exactly as it should.
   I've used torches on many occasions, and they always belonged to the company that I was working for at the time. Can't say that I've ever given it any thought past turning off the bottles after use. Looking at the guages afterwards, was the last thing on my mind.  But this can't be normal.
   I'm guessing that it'll need to be rebuilt. I'm really not interested in buying new Chinese regulators, so if its not an easy fix, rebuilding is the only option here. Even if they were U.S. made, I still like the old school stuff. Besides, I got a really good deal on the whole thing, so there's still several hundred dollars left in the budget vs. new. Any ideas on what it could be? Or should I just move on to contacting a rebuilder?

Offline slip knot

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Re: New to me cutting torch question
« Reply #1 on: December 24, 2020, 07:00:16 PM »
Theres a test procedure to test for leaks in the system but I been away from that work too long. I would be looking for a rebuilder way before looking at a chinamese replacement.

From what I recall, its just a diaphragm and needle and seat. not much in them really.

Offline goodfellow

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Re: New to me cutting torch question
« Reply #2 on: December 24, 2020, 07:21:57 PM »
When you say "shut off pressure at the tank" - do you mean that you close the valve on the cylinder, or do you close off the regulator by screwing the pressure adjustment valve all the way out -- or both?

Assuming that the regulator provides consistent flow and doesn't require constant adjustment (which could mean a diaphragm problem), then it's a matter of pinpointing the leak from the regulator on down.

If you close the cylinder valve and leave the acetylene regulator open, then it could be a hose, hose fitting, flash back arrestor (if equipped), or a seal in the torch handle. Either way, next time leave the cylinder valve open and adjust your acetylene to a few psi of flow. Then shut the torch handle valve and use a spray bottle filled with water and a few drops of dishwashing liquid and spray down every junction and fitting from the regulator down to the torch. That also means checking the fitting that attaches the regulator to the cylinder. Also spray down the entire hose. Watch for bubbles at the joints, or a pin hole leak in the hose.

Lastly with the torch handle valves tightly closed, slightly submerge the welding tip in a cup of water to see if there are bubbles -- if so, then your torch mixer or your torch handle gas valve is leaking (assuming the valve was closed tight to begin with).

Good luck!




« Last Edit: December 24, 2020, 07:24:18 PM by goodfellow »

Offline Kenneth07ex

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Re: New to me cutting torch question
« Reply #3 on: December 24, 2020, 07:44:54 PM »
Yes, it's when I turn it off at the bottle. I used my soap water sprayer to look for leaks. That's how I found the one on the oxygen to regulator coupling. I didn't find anything else leaking. I'll try dipping the handle with all the knobs shut off, see what happens. Glad you reminded me of the spark arrestor. I don't remember seeing any, so I'll probably need to take care of that also.

Offline goodfellow

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Re: New to me cutting torch question
« Reply #4 on: December 24, 2020, 07:50:23 PM »
Yes, it's when I turn it off at the bottle. I used my soap water sprayer to look for leaks. That's how I found the one on the oxygen to regulator coupling. I didn't find anything else leaking. I'll try dipping the handle with all the knobs shut off, see what happens. Glad you reminded me of the spark arrestor. I don't remember seeing any, so I'll probably need to take care of that also.

It's a good idea to get a set of flashback valves. It also depends on what year the torch handle was made. Newer handles (within the last 10 years at least) usually have an integrated flashback valve already incorporated into the torch handle.

Offline DeadNutz

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Re: New to me cutting torch question
« Reply #5 on: December 24, 2020, 08:11:59 PM »
You can take the regulators into your local welding supply and ask them the cost to overhaul them. I would keep the Victors long before buying Chicom.

Offline Kenneth07ex

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Re: New to me cutting torch question
« Reply #6 on: December 25, 2020, 07:33:00 AM »
Turns out, that it is mostly leaking at the bottle coupling. Apparently my soapy spray wasn't soapy enough. It's a long story, I'll spare the details. But with closer inspection I have confirmed the bulk of the leak is the main coupling on both bottles. As I said the oxygen wasn't really a concern, since it held for quite awhile. Now that I've cleaned the couplings and used teflon tape, the regulator pressure seems decent on both. The acetylene still bleeds down faster than I'd like, but we're talking about ten, to fifteen minutes. So I'm okay with that for now.
   The mixing chamber knobs are leaking a bit, as confirmed by dipping the tip in a small tub of water. So that's where I'll focus on first. Any tips on this? Since it isn't the high pressure of the regulator, I'd think that it's completely user serviceable.

Offline jabberwoki

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Re: New to me cutting torch question
« Reply #7 on: December 25, 2020, 11:15:33 AM »
Nice work staying with the good ol USA stuff. My set was scrounged up from swap meets and rebuilt and will probably out last me.

Remember the golden rule....ABC  . Anything but china.
Is the need enough? Or does the want suffice?

Offline Kenneth07ex

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Re: New to me cutting torch question
« Reply #8 on: December 25, 2020, 02:34:53 PM »
Nice work staying with the good ol USA stuff. My set was scrounged up from swap meets and rebuilt and will probably out last me.

Remember the golden rule....ABC  . Anything but china.

I really prefer the older classic equipment. Even when new is the same price, I like things that are rebuild able. There's nothing to love about shiny throwaway junk. If it's made in China, then definitely not.
   Turns out that all this one needed is a bit of love, and care. And sooner rather than later, it'll need the torch valves rebuilt. But I've got it sealed up pretty decent now. The regulators will hold pressure for a couple hours on the one, and all day on the other. The coupling is still the source of the leak at the regulator. Just need to take it loose again, and give it a few more wraps of tape.
    The main problem now is the torch. In a cup of water, it'll give a tiny bubble every three, to four seconds. If I were cutting all day it would be a priority fix. But it's just for hobby, and farm equipment maintenance work.

Offline gtermini

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Re: New to me cutting torch question
« Reply #9 on: December 25, 2020, 03:08:35 PM »
There really isn't anything scary inside a regulator. A spring, diaphragm, and some some of throttling valve. The snout where the adjuster screw goes unscrews to expose the guts. There's a couple teflon gasket rings and a valve seat that could be suspect. There's plenty of youtoob vids showing the guts before you tear in. I wouldn't hesitate to do one myself.

Offline Kenneth07ex

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Re: New to me cutting torch question
« Reply #10 on: December 25, 2020, 04:29:42 PM »
There really isn't anything scary inside a regulator. A spring, diaphragm, and some some of throttling valve. The snout where the adjuster screw goes unscrews to expose the guts. There's a couple teflon gasket rings and a valve seat that could be suspect. There's plenty of youtoob vids showing the guts before you tear in. I wouldn't hesitate to do one myself.

I looked at some of the information out there, and didn't see anything that looked too bad. Some people compared it to rebuilding a carburetor for difficulty. But in all the time between the first post and now. I've found that the real problem is in the torch. Looking at the breakdown of that, as well as the price of parts. It seems even cheaper, and easier to rebuild. I'll just need to find out what kind of sealant to use, something that will work with oxyacetaline.

Offline goodfellow

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Re: New to me cutting torch question
« Reply #11 on: December 25, 2020, 06:34:31 PM »
........The coupling is still the source of the leak at the regulator. Just need to take it loose again, and give it a few more wraps of tape.
   

That may be your problem. Many people mistakenly use teflon tape to "seal" the joint, when in actuality they are making it leak. The regulator fittings were designed to precisely mate up to the cylinder valve and do not require any sealant. They both (cylinder valve and regulator fitting) have polished surfaces and should provide a friction seal when properly tightened. The tape doesn't help much in that regard.
« Last Edit: December 25, 2020, 06:36:23 PM by goodfellow »

Offline Kenneth07ex

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Re: New to me cutting torch question
« Reply #12 on: December 25, 2020, 07:08:11 PM »
........The coupling is still the source of the leak at the regulator. Just need to take it loose again, and give it a few more wraps of tape.
   

That may be your problem. Many people mistakenly use teflon tape to "seal" the joint, when in actuality they are making it leak. The regulator fittings were designed to precisely mate up to the cylinder valve and do not require any sealant. They both (cylinder valve and regulator fitting) have polished surfaces and should provide a friction seal when properly tightened. The tape doesn't help much in that regard.

I understand that the teflon tape might not be ideal. But those fittings are most definitely leaking without it. The acetylene is leaking badly. Couldn't get them tight enough to stop the leaking. Used a 2ft. long wrench, and got it as tight as I dared, then smacked the end of the wrench, one or to smacks tighter.
   So I used the tape, to help me decide what else needed attention, as described in my original post. It works better for now. Although I have no idea how acetylene will interact with the tape.
   It probably needs a new nipple, and coupling nut. I tried polishing the nipple end with a wire brush dremel. Thinking that maybe the built up oxidation might be playing a part in the leaking. It didn't make any difference.
  Once I get the torch sorted out, I'll have time to work on that nipple end. The parts are cheap, and it doesn't look like too much trouble to just screw it out.