I had these good quality white jeans that are now too big for me, and kind of the wrong cut in the legs. Inspired by this jean skirt I saw searching around a bit, I thought I would give it a try. (Link at the bottom) Even though the jeans were too big, I did not think that would be a problem for making a skirt, they would just sit a bit lower on my hips, and the extra width would be fine in a skirt.
Up-cycling here we come!

I like the frayed look, and hope that it will continue to fray as it is worn and washed.

It actually took more time than I thought it would, but partly because I don't sew all the time, so my skills were a bit rusty.

Materials you will need:
- an old pair of jeans
- matching (or contrasting thread)
- some tissue paper or newsprint to make a rough pattern.
- pen to mark up the tissue paper

Sewing tools
- sewing chalk to mark lines
- sewing scissors
- sewing machine
- ruler
- sewing pins
- Seam ripper (not essential, but makes the work go a lot faster, and is not an expensive tool)

Nothing you wouldn't already have on hand if you sew much at all.

Here's the link to the skirt on Etsy that inspired mine. https://www.etsy.com/ca/listing/60470465/blue-jea...

Step 1: Getting a Rough Pattern Made and Opening the Seams

I smoothed out the jeans along what I thought where the natural lines to create the outline for the skirt. Using a piece of tissue paper, I created an outline of what I thought the final shape of the skirt should be.

I decided a finished length of about 21 inches would be about right, but added a couple of inches to be on the safe side, thinking I would have plenty of fabric. Yes and no. When I was done, I was able to cut off a couple of inches of skirt. But there was not a lot of leftover fabric.

Once you have a rough pattern, you will need to use your seam ripper to open the inside leg seams.

Step 2: Fixing the Front

Once you have the seams ripped open, you will turn the jeans inside out, and match the legs for the front of the jeans.
You will need to open this seam too, but not all the way to the fly. Just enough to give you a starting point to make a nice flat front for the skirt.

I basted this with some red thread so I could try it on to see if I had it right.
I did not... I ended up sewing it to a different angle / flatter angle.
You end goal here is to make a straight line from the bottom of the fly, and sew a new front seam.

In the second picture, you will see I top-stitched this to make a nice finish to match the original finish. Not essential, but looks nice.
Try not to poke yourself with a pin, as I did, making bloody marks on the white jeans. (Chuckle.)

Step 3: Fixing the Back

I was kind of hoping I wouldn't need to do much here, because this seam was a flat felled seam (I.e. The kind you usually see on jeans.).
I tried the skirt on after fixing the front, and realized the back was going to need adjusted as well.

I knew it would be hard to replicate a flat felled seam, so I did not try. Instead, I just opened the seam to the point before it started curving, and overlapped the two pieces. Then top-stitched two seams along the curve. Voila, a flat piece of material.

Step 4: Making the Diagonal Cut

The jeans I was using had pockets, so I had to take that into consideration when deciding where to start the first diagonal.
Once you have a plan, draw a chalk line where you want the finished length of this piece to be (this will be where you sew.)
Then add a seam allowance of 1/2 or 5/8 inch. Draw a second line, then cut on this line, both front and back.

TIP
Jeans are cut to allow room for the bum.
When you are laying things out, allow for this by letting the back waist band to be non-aligned with the front waist band. If you line them up, you will find that your finished skirt will be too short in the back.
I actually pinned the waist band out of alignment to keep it that way during most of the construction.

Step 5: Now the Fun Begins! Piecing the Patchwork

Once you have the top all set to go, you get to start the fun part of piecing together the patchwork.
The biggest decision is how to finish the seams.

I decided to put the seams inside out -- this is what it looked like how the model skirt was made.
Instead of "right sides together", you are going to do "wrong sides together" -- the seam will be on the outside of the skirt.

Another option would be just to overlap the fabric, and sew through both layers that way.

You are going to use the leftover parts of the legs to patchwork together the bottom of the skirt.
This is where your tissue paper pattern will come in handy, helping you see how much fabric you need to make.
I pinned the pieces on, marked them with chalk, then cut. (Second picture)
Then would repin before sewing (third picture)

Apologies that I don't have more specific instructions here -- I pretty much made it up as I went along. I would lay out one piece, cut it, pin it and sew it on, then see how things looked.

TIP:
I built the front and the back of the skirt individually, and did side seams at the end.
I decided to sew the side seams the usual way, putting the seam allowance inside the skirt. It was a bit tricky, but requires only patience and careful pinning, no unusual sewing skills.

Step 6: Top-stitching the Raw Edges

This is optional -- you could leave things to just fray in any direction.
But I decided I would lay the seams flat, then top-stitch them in place, for a more finished look. I also thought this would help stabilize the diagonals from getting stretched out of shape, and strengthen the whole skirt.

Step 7: Finishing the Skirt Off

I highly recommend throwing the skirt into the wash after doing the piecing, because it will have pulled out of shape on some of the diagonals, and of course there is chalk all over the place.

Once out of the wash, you can decide how long you want it, and how to finish the edge.
The blue-jean skirt I was modeling this on appears to have an unfinished edge.

I had lots of room to make a finished edge, so I turned under about 1.5 inches and did two rows of a simple hem, not bothering to finish the raw edges. There's raw edges fraying all over the place on this skirt, so what's a few more, right?