From:: I have an old galvanized water tank in a loft how and what can I cut it up with. It is to big to use hacksaw. : There is fire risk with nearby insulation and woodworkI think the only way you will do this is with an angle grinder. You will need to take all the necessary precautions to ensure the sparks dont start a fire. You could also try using a sabre saw or a jigsaw with a metal cutting blade. Take something with you to spray some water onto the timber & insulation.