I think if you're at least a little careful using steam it shouldn't distort, it's probably mostly when someting is cut on the bias . And I have to disagree with the one who said the weight of the iron doesn't matter. I used to not have a dryer and had to hang outside on a line. I had to iron everything and I know it takes more passes with a lightweight iron to get the wrinkles out. heat, steam and weight, When I'm pressing my seams after I have it where I want it I like to give it a shot of steam, seems to make it stay better. I used to starch my blocks when I pressed(they're like cardboard by the time I finish!) but with that much moisture it was easy to stretch out of shape so I don't do it anymore.