I was working on a table runner that I had to sew (9) 40" strips together, with 4 different combinations of fabric. When I ironed them they got distorted, they weren't straight lines anymore. This cause them to be off when I tried to cut them into 9 1/2" squares. What am I doing to make then wavy?

If you "ironed" them, that was the problem. You need to "press" them. No steam, pick the iron up, set it back down. No sideways movement.

That would definitely be a problem for me then. ::sigh:: My blocks are all messed up now.

Spritz with water and press them back in shape ;)

Yeah, there are other things you can do like pinning them until they dry and they will go back into shape. Takes time though.

In this video it explains about sewing strips one way and then sewing the next strip back the other way. Since watching this video I've been doing the different direction sewing and it has really helped keep the strips straighter.

http://www.youtube.com/watch?v=K0LzA..._order&list=UL

When I have to do long WOF strips I sew each strip on in the opposite direction of the previous one - helps to keep them from getting wonky-

Starch can be your friend too. It helps keep the strips from distorting.
Also, lay your strips out straight on your ironing surface. Move your iron straight across them, if you move the iron diagonally as you press the seams to the side, the strip can distort too :D:D:D

press not iron .

and possibly had a curve at the fold when you cut your strips. that means the middle of your strips would have been off.