Suitable sacrificial materials include polymers such as wax and {HEAD ~ epoxies}, metals such as aluminum, and {TAIL ~ glass} 
Suitable sacrificial materials include polymers such as wax and { HEAD ~ epoxies } , metals such as aluminum , and { TAIL ~ glass }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL