Here is the setup, Purox ty 202 torch with older Victor gauges. I just had everything rebuilt this summer, probabally don't have more than 4-5 hours of use on them. Haven't even burned through a tank of gas yet. I was trying to cut some 1/2" plate today for some brackets. I started out with a #3 tip at 5psi Ace. and 40 psi Oxy. I spent several minutes heating and trying to cut and could never get a through cut. I thought the tip may be to small so I checked my chart and Purox says to use a #4 tip at 5/40 psi. Well I didn't have one so I switched to my number 5 tip with the same pressure. It looked to be promising, metal heated up quick started to make my cut and the it happened...... I heard a pop/crack and backed the tip away from the plate, the torch sounded like a pack of firecrackers going off......then the handle and plunger lost all feeling and opened up completely leaving the torch whistling. This all happened in a split second and I shut everything off. The handle was limp and the plunger was not returning. When I removed it the spring and the ball valve on the end of the plunger were completely melted..... Can any of you tell me what the heck happened??? Or what I did wrong???