I'm just about finished with a jeans rag quilt. I'm not sure what to do about the outside edge. I used 6 1/2" squares and have a flannel backing. I have double stitched all the seams. I don't want the weight to pull them apart. Will just double stitching and ragging the outside edge hold over time? I think anything else like using the flannel for binding would be too heavy and thick to sew. Maybe make the edge too stiff too. What do you do?

Maybe use a narrow and short length zig zag stitch?

Did you sew an X or anything thru the blocks? That might add a little more strength to them. But I'm thinking the double seams and the weight of the denim will probably be enough.

Yes, I did "X" in the center with a decorative stitch.
I just don't know what to do about the outside.

If you doubled stitched with a small stitch length that should be good.

I also think you are good to go!

I simply sewed 1" around mine and then cut and ragged them
I did see a youtube video where the ladies did binding, but I refuse to put binding on a rag quilt.

Mine are fine didn't do anything different been to dirt track races, back seat for dogs --no problem washed dozen of times it's a rag quilt :)

I sew 1in from the outside edge of my jean quilts, all the way around, with a multi step zigzag or scallop. Then, I clip the the edges so they will fray.

I also sew a 1" seam line around the quilt twice. Then I clip the edges and wash it so it rags beautiful. Everyone in my family has several in their houses. They all land in the TV room and everyone can snuggle on the couch while dad watches football. The little ones always fall asleep with a ragged edge in their hands. it seems to soothe them some how.