LOCTITE STYCAST HD 3561 LOCTITE STYCAST HD 3561 is a filled epoxy system recommended for potting electronic applications where rigid or flexible wire leads protrude directly from the encapsulation – and where high-impact strength is a critical parameter. It is a 2-part product that requires mixing in the correct ratio with the main material before use. Once mixed, the system adheres exceptionally well to materials such as vinyl or neoprene, and effectively eliminates microscopic cracking on the flexing of leads.