This is the extruder die I made for making hollow glaze test tiles.  This extruder die is made specifically for the Frema extruder as that is what we have in the school.  It uses a metal Z shaped part to attach the 2 pieces I designed.   I will attach a video shortly of it in use.  
 
This is an updated version of the extruder die I made a couple of years ago for our glaze eutectics wall.  This one is a little narrower and I was able to make test tile shape work for a hand held extruder.  Depending on how many tiles are needed we can use the wall extruder or the hand held extruder and the tiles will be the exact same.  
 
Print settings aren't fussy.  I printed ours using PLA, .6 nozzle, layer thicknes .2, 40% fill