OA welding thick square rods

Timur Aydin wrote: > I will try this with the #6 tip also and then will try welding the

OK, I tried this procedure using the #6 tip and it was very scary. When I obtained the smoke free acetylene flame, the torch roaring noise was already quite high. After feeding the oxygen, the roaring and hissing combined became really unbearable. I quickly tried this flame on my 10 mm by 10 mm mild steel bars and indeed, after 8 seconds the metal started to melt and after 15 seconds, there was a large puddle of melted iron!!! Then I immediately turned off the flame, because I don't think one can work with this flame without carrying ear protection :O

One additional observation with this method: I had the torch valves open at max and regulated the flame using the regulators. When turning off the flame, I used the regulator valves again. I first turned off the oxygen and then the acetylene valve. But after turning off the acetylene valve, there was a huge pop. In a second session, the same pop happened. Is this expected behaviour if you turn of acetylene at the regulator valve with the torch valve open?

Also, if I max out both torch valves and use the regulator valves, what is the point in having the torch valves?

Timur

"Timur Aydin" wrote: (clip) Also, if I max out both torch valves and use the regulator valves, what

^^^^^^^^^^^^^^^^^^^^ You're not paying close attention. Go back and re-read what Richard Smith wrote. You don't max out the torch valves--you set them just a little short of wide open, and then use them to make fine adjustments on your flame.

Indeed.

And there are other reasons you provide some "headroom" by controlling back the gas supply with the torch valves.

- the pressure out of the regulator can drift a bit - so you want to be able to quickly compensate at the torch.

- you can, within some latitude, increase or reduce the strength of the flame. The steps in the nozzle size going ... #2, #3, #4, ... enables you to have any exact flame power you want, because you can say drive a #2 harder until that flame strength matches a #3 driven gently

Normally to shut off the torch, you spin the acetylene torch valve shut then the oxygen torch valve. I have seen advice that it is the other way around. Anyone comment? You do get little "pops" as you shut off a torch.

By the way - you get quite loud bangs and the weld pool molten metal flying all over (you!) if you dwell too long in one place and the nozzle gets too hot. Familiar sight in the oxy-acetylene bay of a welding section at a college!

Turn off gas immediately, with great urgency, if the flame disappears into the nozzle because it has got so hot it ignites within - it will melt in a couple of seconds. There is a strange rumbling/shrieking sound if this happens, so you know you haven't simply blown out the flame - it is this much more serious situation.

Richard Smith

Thank you for the explanation, very informative. I have done 20 more welds using the setup procedure that you explained and I was able to complete the welds much quicker.

The noise level of torch is extremely high with these settings, though. Not being used to this level or roaring and hissing (I felt that something is going to blow up), I eventually gave in and got myself a cheap stick welder to finish the remaining welds. I used 3.25 mm 6013 electrodes and a current of 130 amps. It worked out quite well. When I screwed up the weld too much, I fired up my OA set and smoothed out the ugly welds :)

Timur