I have finished my dresden that I did on point but the problem--I used the exact measurements for the triangles (18.25) on the size for my block size (12.5) and now I have a rippled edge where the triangles are.

How can I fix this mess?? I need it to lie flat.

I'm assuming you mean that your block size was 12 inches finished? If so, 18.25 is the correct size to cut your squares for the setting triangles. Is it possible that you stretched the bias edges when sewing the triangles? If so the best solution is probably to take them off, starch the fabric heavily, press it carefully to the right shape, measure and trim if necessary, then re-attach. Maybe there's an easier way - a picture might help.

Did you make sure the edge of the triangles that are on the outside of the block are on the straight of the grain? That could be the cause -- if the outside edges are not on the straight of grain.

To fix it, you may be able to flatten it by spraying it really good with starch and then holding the iron (steam on) and steam it dry -- it can shrink thing up a bit and the starch will stabilize it.

According to the trusty chart that I have, for a finished block of 12 inches (12.5 unfinished) 18.25 is the right size for setting triangles. All I can think of is (1) did you cut the triangles squarely and (2) is the rest of the quilt square. If it's a question of the whole of the quilt being out of square I have no solution but to "fudge" it so that the triangles fit. they may not be 45 degree triangles when you are done, but a man on a galloping horse..........

Okay, I amgoing to be working on trying to fix it and I will let you know. Thanks so much