Cutting with a torch

[souperman000]

I used an oxy/acetylene torch for the first time today. We cut 1/4" steel plates with it. We were making tables to sharpen tools on. We were going to weld but ran out of time.

WHat are your experiences with the torch? I thought it was a pretty sweet rig.

 

[fowler]

They are very useful indeed

I use them every day to either heat or cut large machine that don't agree with what I want to do
Can't say I weld very offern but they are good to weld small stuff that can withstand high pressures

 

[DS13]

Its nice having brazing as an alternative to welding.

 

[Amped]

They aren't just for cutting & welding. You can heat seized parts to help get em apart, blowout welds , bending and cooking lunch. Dumb people should be kept away from them . I saw a guy ( Joe Brock) twisting the torch to get loops out of the hose while it was lit and set his ball cap on fire. It was only funny cause it burned his long hair off the top of his head . Picture a bald guy with a mullet.

 

[OzFab]

O/A cutting torches are awesome. As a panel beater, I've used them quite extensively.

Only 1/4" plate? Wait 'til you get onto the chunky stuff

 

[devino246]

O/A cutting torches are awesome. As a panel beater, I've used them quite extensively.

Only 1/4" plate? Wait 'til you get onto the chunky stuff

x2. A friend of mine cut some swinging targets out of some 3/4" plate for me with his O/A rig. Cut through like butter.

 

[souperman000]

Only 1/4" plate? Wait 'til you get onto the chunky stuff

Actually I think it was more toward 3/4". It was damn heavy.

Out of the other 5 guys I was with, I felt I did the best. Obviously the guy who taught us(The chief at the fire station) was the best. There was no comparison between his nice straight cuts and my angled squigily cuts.

We used up a bunch of the Acetylene, that was another reason we couldn't weld.

 

[mckutzy]

A big point on safety would be, Acetylene ON first, Acetylene OFF first.
So if you want to cut, A(gas) on, Light, adjust o2 for cutting. Shut down, A(gas) off, Turn off O2.

If the O2 is turned off first, there is a potential for the gas(acetylene) while on fire to burn down the O2 hose to the cylinders, this is called a Flash back.

Most O/A setups has dual flashback arrestors and check valves so this is mostly prevented, but still the principal applies. At the welding school I had attended, they had drilled this into our heads about this, so Im passing this on to someone else.

Oh and another thing, it may seem stupid but time and time again I see this and just cringe..... dont cut over your hose lines, be mindful about where they are at all times. Dangerous things can arise.

 

[souperman000]

Oh and another thing, it may seem stupid but time and time again I see this and just cringe..... dont cut over your hose lines, be mindful about where they are at all times. Dangerous things can arise.

That's just dumb! Not a good idea.

We were told to never touch the oxygen valve on the torch, to always keep it on. We adjusted the Acetylene at the hose connection and the whole torch at the top valve.

Some of the other guys were working on an electric kart that had been sitting a while. The tires obviously were flat and had to be reseated. We tried to do it with a ratchet strap but it just didn't want to work with us. So....pump some oxygen into the tire, light the torch, KABLOOM we got a seated tire. Seriously I was loud. Caught all the guys not paying attention really off guard.

 

[machinist@large]

That's just dumb! Not a good idea.

We were told to never touch the oxygen valve on the torch, to always keep it on. We adjusted the Acetylene at the hose connection and the whole torch at the top valve.

Some of the other guys were working on an electric kart that had been sitting a while. The tires obviously were flat and had to be reseated. We tried to do it with a ratchet strap but it just didn't want to work with us. So....pump some oxygen into the tire, light the torch, KABLOOM we got a seated tire. Seriously I was loud. Caught all the guys not paying attention really off guard.

Try a gallon size zip-lock bag filled with 50/50 Ox/Acetylene in an enclosed space.

 

[fowler]

Try a gallon size zip-lock bag filled with 50/50 Ox/Acetylene in an enclosed space.

it always starts out with small bags then theres always someone that brings out trhe bin bag
then it gets serious

 

[OzFab]

LMAO, acetylene bombs, I remember them

 

[exenos]

My tech teacher drilled this one into our heads "A before O or up you go" then proceeded to demonstrate what happens if you leave the oxygen on, about half the shop floor went up in a fireball after he lit the torch. Scared the crap out of a guy. Literally he crapped his pants, the teacher got in a bit of s%*# for that one. But it did sure teach us the lesson.

 

[jamyers]

With an O/A torch, a Saw-Z-All, and a wire welder... I am INVINCIBLE!

 

[DS13]

 

[oscaryu1]

A big point on safety would be, Acetylene ON first, Acetylene OFF first.
So if you want to cut, A(gas) on, Light, adjust o2 for cutting. Shut down, A(gas) off, Turn off O2.

If the O2 is turned off first, there is a potential for the gas(acetylene) while on fire to burn down the O2 hose to the cylinders, this is called a Flash back.

Most O/A setups has dual flashback arrestors and check valves so this is mostly prevented, but still the principal applies. At the welding school I had attended, they had drilled this into our heads about this, so Im passing this on to someone else.

Oh and another thing, it may seem stupid but time and time again I see this and just cringe..... dont cut over your hose lines, be mindful about where they are at all times. Dangerous things can arise.

Oh dear, you have it backwards. When you shut down an O/A setup, you shut off the oxygen valve, followed by the acetylene. Shutting off the acetylene first has the potential for "flash back", with the acetylene flame trying to travel back down the oxygen-rich hoses and burn them inside out.

 

[mckutzy]

As for the definition of a flashback I may be wrong Its been a while I have had to think about that one.
But, I just took a good look on the google for what is the correct procedure on shut down. It appears there is varying schools of thought on Gas or Oxy first, mostly citing the regulator or welding kit's manufacturers recommendations.

I happen to have been educated by the school of Acetylene off first, alongside exenos.
A before O.

So Op, I guess by this statement, an old adage... Consult the owners manual.

 

[SpeedBoy]

I used one on a feild trip for school one time and i absolutly loved it. I use a angle grinder right now for everything i do and everytime i get into thick steal i think of using that torch and it cutting so easy. I would get one but way to expensive for me considering im only 15 and don't have a real job and cant order a used one off the internet :/

 

[jamyers]

Oh dear, you have it backwards. When you shut down an O/A setup, you shut off the oxygen valve, followed by the acetylene. Shutting off the acetylene first has the potential for "flash back", with the acetylene flame trying to travel back down the oxygen-rich hoses and burn them inside out.

That's what I was taught as well. Acetylene is the first and last one on or off.

 

[falcon52]

Yeah in my high performance welding class we had to use a torch to weld aluminum. They taught us about the three different kinds of flames (neutral, carterizing (sp?) and oxidizing) as well as how to set up and shut down a torch and purge the lines and all that jazz. Even the oxy to acet. ratio. Then, I go home and use my grandpas torch for something and get yelled at because I wasted gas by purging the lines lol.