Originally Posted by BellaBoo

I use a Clapper (Tailor's press) on all my seams. It does make a big difference. An old flat iron will work great and a heavy bacon press will do the same job. You want something heavy that will absorb the heat from the fabric fast after you press the seam flat. The hammer flattening will eventually unflat if not pressed and sealed in place by removing the heat fast. The tailor's press wasn't used for the fun of it. It works.