Figure 1. Propane source and injector. A: Propane canisters in a variety of sizes and shapes are readily available as camping stove/barbecue fuel, and for use in copper pipe joinery. The brass torch adaptor screwed to the top was specifically for copper pipe use, and is available at most hardware stores. The diffuser was unscrewed from the tip of the torch to reveal the pinhole outlet. B: The inverted propane tank will eject liquid propane that remains liquid as it hits the dry ice–chilled PCR blocks.