Actylene welding question

"Ivan Vegvary" wrote:{Smith}gets hot to the touch near the torch valves. (clip) my Victor never gets hot. (clip) about 4 months ago I destroyed a Victor rosebud. It started getting hot at the tip attachment nut and in a matter of seconds it melted and dropped to the ground. (clip) ^^^^^^^^^^^^^^^^ I have never used anything but a Victor, so I can't be sure about the Smith, but it is clear to me that two different things are going on. The Victor rosebud had a flashback into its stem and got VERY hot in a few seconds. If this happened to the Smith, it would do the same thing. Furthermore, when you get a flashback, the sound and the characteristics of the flame change--so it doesn't seem like the Smith is not having flashbacks. You can adjust the inner and outer cones normally? It's probably normal for the tip to get hot, though I can't see why. Have you had this happen with different tips?

Sounds like you have a leak in the mixing chamber that's burning internally---take it to a welding supply outfit & see if someone will look at it. Jerry

Ive used oxy and acety for many years with many different torches. the key to avoiding any flashback is to have the right gas pressure for each tip size. The flame rate of acety with oxy is very fast, more than 5 times faster than propane and oxy. So do look up the right pressuresfor the tips you will be using. Any flashback is a result of too low a gas pressure. .

The flame burnt back. Seems you didn't have enough flow. I wounder how someone can not realize that it burned back. The noise is very typical.

Nick

Didn't he say that the body near the valves got hot?

b

Can you read? Then read what I wrote! You *hear* it right at the moment it burns back. If you feel it, it is already too late.

Nick

He is concerned now about the safety of using the Smith torch, fearing that he could have a repetition of the experience when he had a flashback on the Victor. Since I am sure he is not having a flashback on the Smiths, all the advice on how to avoid it is not helping him.

Ivan, try different tips and see whether they all get the valve area hot in the same way. Does it keep getting hotter as you use it, to the point where you can't hold it, or are you stopping because you want to be safe?

It would be good for someone who is familiar with Smiths torches to jump in here. It doesn't help Ivan to have us arguing about flashbacks.

Why not? If the handle gets so hot, the tip must be **way** hotter. And then he would get bangs without doubt. And it really takes a long time welding in tight places until *that* happens. No matter what brand he has.

Nick

"Nick Mueller" (clip) And it really takes a long time welding in tight

^^^^^^^^^^^^^^^^^ Quoting your response to b: "Can you read?" The OP said it happened in about five minutes.

I also have a small Smith's , and it does not get hot anywhere but the business end . Check your o-rings and gas pressure . I run about 6 psi Acetylene and 20 psi 0xygen for welding , 7/25-30 for cutting . When I got mine , the cutting tip was horrible . The crush gaskets were worn out . New tip and it's a dream to cut with . Number 2 (I think) welding tip does a fine job for welding on exhaust pipes .

Nick, could you please describe the noise. I do get an occasional pop, but I have always assumed that my parent metal is not uniformly hot. Correct me. BTW, the torch handle is not hot at all. On this particular torch (Smith) the valves are between the handle and the tip. The entire area on the flame side of the valve (5 inches ±) is hot. Where I hold the torch (handle) it is not hot.

All the comments relating to not enough gas flow on the rosebud are interesting. I will read the Victor brochure and set the gas pressures accordingly.

Thanks Nick,

Ivan Vegvary

And make SURE the seal at the mixer is adequate. Some have "O"rings, some just tapered brass. Any leakage there can cause a hot handle, apparently.

Too late for what? And, no, I can't read.

b

Go back and read the OP. When he used the rosebutt and got the flashback, it took seconds to melt it and drop to the floor. If you wait seconds, it is too late to turn off the acetylene. You have to do that as soon as you hear the screaming sound.

Nick

The normal sound of the burner has a constant sound and amplitude, kind of rushing. When the flame is burning back, it sounds like a pulso-jet. Not that loud, but constant explosions with a very high frequency, kinda screaming. Then you do have to close the acetylene valve at the handle and then at the bottle. Quickly! Hope you have flame arestors! It happened only once to me, but that sound is so much different, that you realize it, even if you didn't hear it before.

You get the pops when the tip is getting to hot. Then the acetylene dissolves when reaching the tip and does not burn outside of the tip. You could cool the tip or adjust a bigger flame to get more throughput of gas.

I meant the valves (body), sorry.

The valve should not get hot. Of course, the burner gets hot, but you should be able to touch it on the other end of the tip. There is something wrong (you knew that ). If you have leaks, it doesn't make things hotter, just hard to adjust the flame.

2.5 bar for O and 0.5 bar for A are a good rule of thump.

Nick

He is talking about the Smith. The Victor is merely ancillary information.

b

What I quoted, I answered.

BTW Quoting: Seems you need to improve that.

Nick

2.5 bar (36.75 PSIG) sounds rather high for the oxy, except for cutting. Smith recommends more like 10 PSIG for welding tips, 10 to 14 PSIG for rosebuds.

I expect Victor is quite similar.

BTW, "rosebutt" is not a welding tip term. It's a symptom of sitting in front of a monitor too much...

It does have to do with gas, sometimes.

Thanks for the correction!

Nick