I am making wedding sheet cakes. On the chocolate cake pieces I want to make 3D chocolate (lacey) designs to decorate the top of each slice. Should anything be added to melted chocolate before piping design to help it stay firm when placed upright (3D) on cake slices...don't want it bending/melting before being served.
Actually wilton has a inexpensive candy mold that has several swirls etc for chocolate pieces such as what you are wanting..I made them for my black forest cake....here is the link to look at the picture...
Don't add anything to the candy melt chocolate..just melt and pipe in molds.