# Oxyfuel flashback arrestors?



## FliesLikeABrick (Jan 22, 2022)

Hi all,

I am looking into purchasing my first oxyfuel setup.  After reviewing some past threads, the message about safety considerations of buying decent equipment have landed well with me (Versus starting with cheap import or unknown history/abused used equipment).

One of the threads recommended the Victor Journeyman setup, I believe referring to https://www.northerntool.com/shop/tools/product_200934228_200934228 (along with multiple folks seconding Victor as a solid brand that some had decades of experience with)

When it mentions "(1) Set of built-in flashback arrestors" -- what are these integrated into?  If not integrated, where are these normally located?     

Follow-up questions may continue once I'm given a bit of background and direction that I seem to be missing.


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## jwmelvin (Jan 22, 2022)

Built into the torch where the gas lines connect, I believe. I understood that to be where they go if added separately.


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## JimDawson (Jan 22, 2022)

They are in the Y looking portion of the handle just downstream of the valves.


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## FliesLikeABrick (Jan 22, 2022)

Thanks.  So if these weren't built in, they would be separate items attached in-line between the hoses and the torch?


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## JimDawson (Jan 22, 2022)

FliesLikeABRick said:


> Thanks.  So if these weren't built in, they would be separate items attached in-line between the hoses and the torch?


Yes.  



			https://www.grainger.com/product/VICTOR-Flashback-Arrestor-Set-5KJ54


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## FliesLikeABrick (Jan 22, 2022)

Gotcha thanks.  On a set like the Journeyman 450, I see the way they're marketed with the max cutting+welding capacities (with the right tips and pressures, of course).   Is there a practical lower limit I would expect to be able to braze/weld with this?  Not talking "jewelers" small, but open to input on sizing.  I have not done any gas welding but do have brazing, cutting, and general heating needs on the horizon where map will not cut it


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## JimDawson (Jan 22, 2022)

With a #000 welding/brazing tip you can do some pretty fine work.  Not sure if they make a #0000 tip, but that would be tiny.


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## benmychree (Jan 22, 2022)

For oh so many years, flashback arrestors were not even thought of; the torch popped back, oh well, no damage was done, still I suppose damage might have been done, possibly to the regulators, but finally someone thought to design the arrestors; I've been welding of at least 60 year without arrestors, and the welding world did not end ---


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## Downunder Bob (Jan 23, 2022)

Likewise, back when I was an apprentice, 1960 to 1966, we didn't have any flashback arrestors, even though we had many oxy acetylene sets. Torches often popped back, but I don't recall any one actually being hurt, or equipment being damaged. 

I have owned two oxy sets over the last 50+ years and it wasn't until I got the second one during the 80's that it came with arrestors, they were not included inside the torch, but were like a little barrel union fitting that was fitted between the torch and the hoses.

Also many of the ships I have worked on had oxy sets and it was not until around the 80's that we got supplied with the arrestors. And yet I've never heard of any accident or anyone being hurt.

I suppose it's technically possible for a flashback to be dangerous, but in the absense of any actual event, how likely is it?

The torch will still pop back, so can not notice any difference in performance or function.


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## ericc (Jan 23, 2022)

All modern torches have flashback arrestors or combination back-flow preventers.  The Victor torches have integrated ones, and the Miller-Smith have add-on ones provided in the kit.  They are a good idea to have, although acetylene is more dangerous in regards to flashback, since the burn velocity is greater and acetylene can self-react in its hose.  Even oxy-propane can benefit, since even though propane cannot flash back, there can be dangerous back flow conditions in which oxygen can get into the propane hose and then flash back.  I have a friend who is an EMT and he saw two people die from a torch accident.  He suspected flashback.or oil in the oxygen regulator.

I have pretty much only used old torches without the modern safety attachments.  There is a procedure to improve one's odds.  Soap the torches, valves and connections with an oxygen safe mixture and resolve even small leaks.  Keep the tip clean.  If there are any pops, find out immediately why they are happening.  Do not just relight the torch and go on.  Typical reasons are insufficient gas flow for cooling the tip, dirt in the tip, or too close of a work spacing.  Any strange noises, especially whistling, means immediately turn off the torch and find out what is going on.  Dirty metal, sparks or bb's flying around are to be avoided, since if any of that stuff gets in the orifice, it can cause a dangerous backflow condition that might prove difficult to react to quickly enough.  I am sensitive enough to gas prices so that I set everything up very carefully and do not run the torch long enough to get it very hot.  I was at a blacksmith demo where the team was running a large rosebud on a manifolded system.  It suddenly exploded and it ended up like one of those cartoon exploding cigars.  It was fortunate that nobody got hurt, since there were a lot of metal pieces in the air.  Somebody dug up the receipt for the tip, and it was a propylene or MAPP tip, and they were feeding it acetylene.  Nobody thought to check until after the incident.


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## Eddyde (Jan 23, 2022)

I had a close call with an acetylene torch. Back in the late 90's I was part of a team, renovating a floor of the Knickerbocker Club in NYC. in one of the rooms there was a heavy piece of steel angle protruding a few inches from the concrete floor, in a place that was formerly a wall but now was to be open space. It was about 6"x4" and a ½" thick, someone proposed grinding it off but that would have taken a while and we only had one cutoff disc. Earlier, I had noticed a Oxy-Acetylene rig in the clubs shop, so I offered to torch it off. The club's head of maintenance brought up the torch rig which appeared older but hardly, if ever used. It was already set up for cutting so I just checked the connections and started cutting the steel. I got most of it off and was going back to knock off a bit that was still sticking out. Suddenly there was a loud whistling sound and flames were shooting out from the base of the torch, one of the most heart-stopping moments in my life! I immediately shut the tank valve and it stoped. Upon examination it there were plastic seal washers where the hoses connected to the torch, the one on the acetylene side was split. I had never seen these before, I doubt they belonged there. Maintenance guy said the torch had been there when he was hired about 15 years prior and that he had never seen anyone use it. I don't know if it was a flashback or the leaking gas simply ignited from the torch. Either way, it was a very learned lesson.


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## Bi11Hudson (Jan 23, 2022)

Away back in the old days, I had a crew hanging a new conduit run over the annealing ovens. The ovens were cool, the conduit was for an upgrade to the oven controls. A spark(?) burned through the acetyline hose at the regulator and it caught fire. The regulator burned down to the tank, increasing the flame. I notified the crew up on the staging. They ran. As did I. We notified the appropriate people and then hung around the mouth of the oven, watching. The salesman from the welding supply house calmly walked up to the torch buggy and valved off the oxygen tank. He then wheeled the buggy out to the "pipe run" to an open area and let it burn out. We were told there was no explosion hazard and with the oxygen off in an open area, no real fire hazard. 

Shortly thereafter I acquired my own torch rig for home use. As soon as the arresters came available, I acquired a set and mounted them on the torch. Just another sea story from the old (pre OSHA) mill.

.


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## Nutfarmer (Jan 24, 2022)

Something interesting I learned in the fire service on dealing with propane tanks was not to put out a fire coming out of a leaking tank if it couldn't be turned off. This is counter intuitive to what one would think. The thought behind this is that  the gas being heavier than air if leaking and not being burnt off will settle in low areas and create an explosive condition. One thing I still remember to this day when the Roseville train yards blew up was the mushroom cloud from the propane tank cars that bleved. They looked just like the classic nuclear explosion mushroom we see in pictures.


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## ConValSam (Jan 24, 2022)

Is there PM one can perform that will minimize the risk of these types of events? 

I bought my setup only a few years ago, but I would hate to experience anything like this because I failed to inspect my gear.


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## Nutfarmer (Jan 24, 2022)

The most important thing to check for are leaks. Never use any oil or oil based sealants on the oxygen . Common sense goes a long ways in preventing any problems. Check the surrounding for anything flamable.


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## ericc (Jan 24, 2022)

Get a little folding tip cleaner and keep the tip clean.  Little hot specks can cause flashbacks or even worse plug the orifice.  If the tip gets wallowed out from too much enthusiastic cleaning, replace it.  Don't get the tip too close to the work, since something might blow back into it.  When working in a confined crevice which is hot, avoid getting the tip too hot to discourage burnback.  Keep the flow rate at the minimum suggested in the manual, else there isn't enough gas flow to cool the tip, and again troubles can occur.  The rule about avoiding oil-based fluids is very strict on the high pressure side of the regulator and less strict on the low pressure side.  Still, don't allow grease to accumulate on the hoses, and oxygen-safe soap or sealant is safer (get these at the welding store).


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## FliesLikeABrick (Jan 25, 2022)

Looks like I'll be investing in the Victor Journeyman Edge 2.0 kit.  Cyberweld.com has it for basically Victor's wholesale price ($535) which is barely more than what some places charge for the original Journeyman 450 kit - but the new one comes with a hose, extra welding tips, and a few more things -- including a tip cleaner


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