Following a chat with Stephen Geddes and his suggestion of doing a trial with different kinds of waters, here’s 4 cones I poured today, all with slightly different mixtures. All a very basic mixture, Plaster of Paris, sand, different waters, no added salt, just a splash of the Kitchen Sink homeopathic mix. 2 are the same except I carelessly left out half the sand in one, so had to do another with the right quantity of sand. Those two had half seawater/half rainwater. Another was seawater/crystal water. The 4th was ‘neat’ seawater. I used a percentage of hot water into the mixture, which caused them to set REALLY quickly – one set so fast I hardly had time to get the mixture into the mould. They all became very hot and remained so for at least an hour: Unfortunately they are not identical in weight, but pretty close. Now hoping for comments from Stephen. Do you want me to identify which cone is which before you comment Stephen; or do a ‘blind’ trial? Anyhow for now they are unidentified 🙂 In order, they are cones A, B, C and D.