I want to bend some exhaust pipe to make a manifold. I can't afford a mandrel bender, buying pre-bent sections is very expensive and I don't want to weld countless bits of tube together. I've researched this topic and the best results I've seen on YouTube not using a mandrel bender was with heat. There's several vids from Japan of people making manifolds for bikes and the results are impressive. I think the pipe is filled with sand and then heated with a blowtorch. I have sand. I have exhaust pipe. What blowtorch can I use? I can't afford an oxy-acetylene set up. Will a large propane blowtorch produce enough heat? I'll be experimenting with mild steel pipe before trying stainless steel. Not sure if this method can produce tight bends though. Advice please.