I'm putting a flat fondant cross on top of a cake. I ended up putting it on in three sections. How can a smooth out the separation lines?
I've been able to minimize lines by using water, crisco, a little spare fondant, and patience. Use a drop, just a single drop of water on your finger and very gently rub/smooth it over. When it gets tacky, or you feel it's necessary, use a little crisco and do the same thing. If you do it a little too wrong and put a dent in it, that's when the tiny bit of extra fondant might help for filling in. I'm so new to it, so I don't know exactly the right way to do it, but this is what I've done to fix holes. When it dried it looked perfect. HTH
Sharon Z. uses crisco on her Boxes & Bows DVD for the seams where she is piecing the boxes together. She just rubs it into the gap and that is usually enough. The shortening is absorbed into the fondant after a little while. You would probably want to rub it into the whole cross so that you wouldn't end up with a little different appearance from shortening/no shortening.
I haven't tried it, but it certainly works for Sharon.
mbt4955 just made me think about something...is your fondant colored? The way I was repairing was with blue fondant that I colored. I've heard you can use shortening or buttercream for fixing things if it's just white.
Sharon used it on a black lid on her DVD and it wasn't just a seam where the two pieces met. There was actually a little bit of a gap. You could still see the line, but you really didn't see the gap anymore.
BTW ... Boxes & Bows is great! I was dog sitting over the weekend and didn't feel like dragging my whole life with me, so I had nothing to do but sit there and watch my DVD's. Sharon, Michele, Jennifer, Nicholas and I had a wonderful time!