I needed some quick and cheap fluid filters for a prototype piece of field research equipment. Here's a quick way to make coarse and relatively fine fluid filters of almost any diameter and contour shape (round, square, irregular etc...) using a simple trick where you create a solid object like a shallow cylinder then STOP the print just after the raft is set down and BEFORE the object starts printing. You are using the RAFT as the fluid filter not the object that defines the contour. You have a useable fluid filter in less than 3 minutes that has a "pore" size down to about 50-100 microns (yes I checked on an optical micrometer). The pore size can be 1mm if you only let the first layer of the raft print. It goes down to 50-100 microns if you let the overlying raft layers print also. You can also eliminate the outer rim if you want by changing the settings for the print. One nice feature is the automatic support bars that are laid down under the raft. I printed this on an UP!3D printer at normal resolution.