Filaments I used (had handy): Makerbot True Purple PLA Makerbot PLA Natural. Printer: Makerbot Replicator 2 Low Rez 25% infill. Hexagonal Pattern. Shells: 2 Rafts: No Supports: No Parts friction-fit together. If you keep pulling the parts apart and putting them back together, they will not fit as snugly... but you probably knew that! You may want to sand the inside of the air chamber so there is less resistance as the plunger fires.