Mix your polyester resin inside your large bowl, following your resin’s packaging instructions.
Pour your resin mixture into the cookie sheet, filling it to the top of the cookie sheet’s edges or to at least 1 inch of thickness. Spray your filled cookie sheet with your resin setting spray and then allow it to sit for up to three days or however long your resin’s instructions direct.
Paint your dowels and newel stair posts during this waiting period; you’ll want to paint your dowels since they’ll be visible through your clear tabletop. Allow your painted items to completely dry.
Turn over your resin-filled cookie sheet and pop out the hardened resin. If it doesn’t fall out easily, try peeling back the cookie sheet by the edges.
Fit your stair posts to the edges of your resin tabletop, matching the edges neatly. Draw around the stair posts with your dry erase marker. Mark the center of the squares you just drew.
Drill into the center marks you made, going all the way through the table top. Wipe away all your marks.
Drill into the center of your newel posts, going an inch into the posts. Insert your dowels into the holes you just drilled. Lightly hammer your dowels into the posts to firmly embed them.
Insert the emerging ends of the dowels into the holes you drilled into your poly resin tabletop. Firmly embed them into the tabletop to complete your poly resin table project.