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..
That's a variant of Kerrs Satin cast. Jewelry guys have been using it for almost 100years. Interesting thing here and news to this guy... Kerrs is now DEFUNCT. I just talked to Rio and they now are selling Ransom & Randolph Bandus Ultra-vest. 50lbs runs about 48bucks. Anyone that has ever used this stuff can tell you it does not go far. It's the best for jewelry work that's for sure. Speaking of jewelry, check this new video from Paul here in texas. This was done on a cnc printer. I wonder if he can do me some fancy stuff for an AR-15?