Pyropen butane gas soldering iron with gas cylinder The Weller Cordless Pyropen is a manually ignited butane gas-powered soldering iron with soldering, hot-air and soldering torch functions. It is ideal for soldering on the go and helps to complete soldering tasks anywhere, without the need for a mains connection or annoying cables. The butane gas soldering iron features a fast heat-up time and an operating time of about 3 hours with one filling. It offers continuous temperature adjustment from 200°C to 500°C when used as a soldering iron, up to 650°C when used as a heat gun and 1300°C when used as a soldering torch.