Question: How do I make the mold for casting my coaster ?
Options:
Use an old laminate shelf, cut a  12" by 12" square from it and four 1" by 12" strips that will be glued to the sides of the square with super glue.
Use an old laminate shelf, cut a  12" by 12" square from it and three 1" by 12" strips that will be glued to the sides of the square with super glue.
Answer: Use an old laminate shelf, cut a  12" by 12" square from it and four 1" by 12" strips that will be glued to the sides of the square with super glue.