The easiest to obtain is T6. This is architectural sheeting that cuts just like wet butter.WD40 is the best coolant for aluminum. It in fact seem like that is all it does well in. given that it is expensive, it’s good that you make your own 75 percent paraffin only using the UK stuff . Also, make 25% of any hydraulic oil, or ATF- the red automatic transmission fluid. You just require a little of this. The small kitchen type spray bottles will work best, but your presence is important. You will hardly wait for ten minutes and the alloy will have build up on the cutter and as you are about to stop your machine you get hit by a huge snot of muddy water. A fine mist is all you need, with of course a decent ventilation.