I've seen lots of wedding cakes lately with very thin buttercream horizontal stripes. Any idea of how to do it? Do you actually pipe them or use a comb? Thank you!
Determine the circumference and height of your cake and use wax paper strips to cover the cake, leaving openings for whatever height you want your stripes to be. Ice the openings, smooth and remove the wax paper. It should leave you with clearly defined and smooth stripes.
For example, a 6 x 4 inch cake with one 1/2 inch stripe. The circumference is 18.84 (6x3.14), so you'd need 2 pieces of wax paper about 20 inches long (overhang is good!), and 1.75 inches high. Place one strip around the bottom and one around the top, leaving 1/2 opening between the two for the stripe and ice the gap.
You could also pipe it, but it would require am incredibly steady hand.