How about that, I was pumping out some dings with compressed air @50psi and using oxy/acetylene to heat on the week end.
The whole time I was wondering if the juice was going to be worth the squeeze as you warn of in your reply Big K.
It is a sketchy process, even small pressures can make a big bang. So 50 PSI is going to go big.
Any how, moral of the story is that it is potentially catastophic heating a vessel under pressure while observing the process at arms length - especially a thin metal chamber not rated or built for these pressures.
The result was very impressive in any case, nicely repaired pipe for minimal effort. I will build a cage to do this in the future. Similar to a tyre inflation cage, the concept is to contain the pipe if it blows.
There is still scope for the pipe to blow fragments and the potential for injury is still very present but hopefully the hazard can be reduced with the use of protective devices and protective gear.
I would be very interested to hear a blow by blow recollection of events from Big K to assist in designing a cage to contain a blow out. Maybe a Ned Kelly suit?
Hydroforming using high pressure water - you tube it. Looks real good and the operator can stay at a respectful distance from the pipe.