Spray Welding Torch Problem

[817jdg]

Hi a friend gave me this Dytron Alloys spray welder. When you attempt to light it I have problems. You get it lit and adjust it down to a nice flame about the time you are satisfied it goes BANG and the flame is out. What is causing this to happen?? I have looked over the O rings in the torch everything seems to be in good order. Thanks

[hammermill]

Pressure are not balanced, to much oxygen????

[steamin10]

Torches with this problem invariably have leak issues internally. They have a mixing jet that must keep the gases separate, until they enter the final area. Over heating, an internal fire, flashback , can make the o rings fail and the problem just gets worse. Replace all the o rings, or send it in. Make sure you are using the fuel gass intended for the torch. I have seen mapp and natural gas torches used improperly, so do some research and dont get bit by misapplication.

[redneckalbertan]

Pressure are not balanced, to much oxygen????

I am in no way familiar with this torch or process. But with torches the gasses must be flowing out of the torch head at a speed faster than the rate at which they burn or the flame can go back up into the torch head and cause the symptoms that you are experiencing. The bigger the orfices in the tip the more pressure is needed to keep those speeds up. With welding/brazing torches and rosebuds you should have your regulators balanced cutting torches you can't. If you do need your regulators balanced try turning them up otherwise turn up your fuel gas pressure.

A bang is usually a good thing the flame is usually extinguished in the explosion (backfire). This happens in the tip or mixing chamber of the torch if the mixing chamber is not a part of the tip. If you hear a high pitch squealing or black smoke appearing from the tip with no flame shut your fuel supply off immediately. This is a burn back, the flame is now burning inside then torch head or torch body. If you have this fire run up your hoses you now have a flashback situation and flashback arresters are a GOOD thing to have immediately after your regulators. If your torch is balanced flashbacks can not, in theory, happen.

Clean your tip as well it may be something as simple as a speck of metal on the tip changing how the gasses flow out of the nozzle making the situation conducive for pushing the flame up the tip.

[PeteH]

Red,

I thought you were supposed to put the flashback arresters right behind the torch body, not up at the regulators.

Do I have this bass-ackwards ?

Thanks...

[hammermill]

my understandind is flashback arresters go at the torch, check valves go at either as they prevent abnormal flow and back flow.

some design incopriate both and go at the torch.

as a side note victor has been bought by esab.


in some locals and via a local safety comittee flash arresters also are seen after the regulator.

[steamin10]

Several places I worked at used them on either end of the hose, as they claimed it does not impead the working processes of the torch, hence a double safty.

I have had a bad torch blow one of the lines apart at the torch handle on lightup. That will get your attention. It is the common enough reason to use the flash preventers.

(If you are rough on the torch and drop it all the time, You will break the fittings sure enough. Over time, been there too.)

[redneckalbertan]

The flashback arresters that I am familure with are big and bulky and would not fit on the torch body, however I just did a quick google search for flashback arresters and see that there are a good selection out there of slim flashback arresters out there that would fit behind the torch. I have mine after the regulators that way the bottles are protected if something falls or drops on the torch hose. I think the possibility of something like that is very slim but that is where I put mine. You won't be able to take a set of flashback arresters designed to go after the regulator and put them in front of the torch body without the need for adapters other wise the check valves will be forced shut. Flash back arresters that go at the regulator have a female inlet and male outlet. Those designed for behind the torch have a male inlet and female inlet.

In school it was explained to me that Flashback arresters have two functions: one a check valve and two a solder like material that melts at a low temperature and will seal shut if there is a fire.

I have quick connects on my torch hoses and torch bodies. I have 4 different torch bodies that see use and it is nice to quickly be able to change them. A standard victor hand operated torch. A smooth victor long body machine torch. A smooth victor short body machine torch and a victor machine torch with a rack on the side. The quick connects that I have also serve as check valves. Here are some google pictures. The quick connects that I saw first aren't the style that I use but are the same thing. If you get quick connects there are 3 different sets. A set to go between a regulator and the hose, a set to go between the hose and the torch and a set to make up an extension torch hose. The only difference is what type of threaded fitting is where to make sure the check valves are in the correct orientation. The quick connect fitting female is always on the source and male quick connect fitting is being supplied. Same as air fittings.

As a side note air liquide quick connects are the same as princess auto quick connects and the princess auto are cheeper!

[redneckalbertan]

Here are two of the quick connect sets from princess auto. For anyone who doesn't know about princess auto they seem to be about the same quality as horror freight but Canadian. Cheep Chinese crap makes up a lot of what they sell, but everyone in a while they have something decent. I think that these quick connects are and at half the price of others, I think its a deal. They readily interchange with the air liquide fittings and I haven't had an issue with them yet. I have been using them for the last 7 or 8!years.

http://www.princessauto.com/pal/en/sear ... searchForm