My second go at lost PLA casting, I am pleased with the results. As the pattern had a flat bottom it seemed a good idea to just use investment for the drag and and greensand for the drag, saving time and money on plaster. I was not sure how long the PLA should be burnt out for but after 2 1/2 hours I checked and it had all gone ant the oven temperature was around 700C. The plaster was intact so I figured the hot metal would not crack it. The original STL file had holes to mount other parts so I edited these out and also added some extra material for machining. Here are the results..