What causes this?
 

I'm on a mission to solve my quilting problems. So I think this may be a problem as well. I'm using a 503, the pressure foot is set as low as I can set it without going to darn.

On the green one, I just took it out of the scrap bag and sewed it.

On the blue one, I pressed it flat before I sewed it.

Now, if I press them, they will be flat. However my quilt has wavy edges and I don't think I eased the seam, as there was nothing to match there.

I'd really like to improve my quilts, so I'm looking at everything.

(As an aside, the bobbin tension needs to be adjusted. I just watched a video by archaic arcane, so will do that tomorrow morning.)

bkay

[ATTACH=CONFIG]580245[/ATTACH]

[ATTACH=CONFIG]580246[/ATTACH]

I always get a better result after ironing the fabric, on almost anything, and it is a must sometimes. I even irion edges, seams, hems, bumps, binding, etc, and it makes a difference. I don't know if there is any way about it. It makes layers flatter and more even against each other. For the long strips, there is a trick to lift them up after the needle is lowered, slightly stretching the pieces and aligning the layers as you go along. This is when a walking foot can improve results too.

it's hard to judge w/o watching you sew. but, from personal experience when i first started quilting, using strips, i found that i tended to pull slightly on the strips as i sewed resulting in wavy sewn strips as in your picture. while teaching my grand daughter to sew on machine i've had her concentrate on going moderate even speed with fingers guiding, not holding, the fabric strips with very light pressure.

your border looks like it was too long and then pressed which made it wavy. i measure my quilts across the middle vertically & horizontally ..pin border strip at corners, center, then center again and again til pinned. i also know that many quilters are not the pinners that i am. but i learned to sew via clothing & household items like draperies etc ..pinning is fitting and i continue the method with my quilt assembling.

looking at the green, My first guess is your tension is too tight. ..... It may be balanced, but tight. Try loosening the bobbin tension, then resetting the upper tension to balance with the new looser bobbin tension. Stitch another strip and see if the waving has relaxed.

roguequilter's point on pullling is a good one. Done that myself.

As far as tension goes there are two great sites I found helpful if you have time
https://www.youtube.com/watch?v=ikIn...EB93&index=115

Quilty Youtube videos were really helpful though I had made quite a few quilts before watching.
Superior threads has a lot of great info too. Sure hope these links work as I've never done it on this site before. :)

http://www.superiorthreads.com/education/thread-tug-of-war/