Making jeans

Not too long ago, I read post on someone else's blog about jeans. It once again reminded me that I could use another pair myself. The post also contained a bit of a surprise for me: There was a picture of the insides of the finished jeans and none of the seam allowances had been finished in any way. There was topstitching along some seams but all the edges were raw. 
Not a treatment I would ever recommend for denim. This, rather experienced, seamstress told me she had never had any trouble with the particular kind of high quality denim she uses. 

And now, I am making jeans again. Another pair of my close-fitting jeans, using stretch denim. I'm making them using my normal method. I've done this for quite a while and generally don't give it a lot thought. However, based on that recent discussion I thought it might be worth showing after all.

I like to use flat-felled seams on my jeans. I use them on all those seams which you will usually see flat-felled or topstitched in RTW. Yoke seam, center back seam, inner leg seam. 
Years ago, before I had a serger, I would sometimes try an flat-fell the outer leg seam as well as the inner leg seam but I would recommend that. It's really fiddly. 

This is what I do now:

For my flat-felled seams, I use topstitching thread in sewing machine's needle and regular thread in the bobbin (topstitching thread is thick and likely to get stuck in the bobbin). This works really well but it does mean that you had to plan ahead where you want the contrast stitching to show.

The first step is to sew the seam with the wrong sides of the fabric facing each other and stitching on the side you want to be on top in the flat-felled seam.

This is what the other side looks like.

Then, I press the seam allowances open,

trim the seam allowance on the side that has the stitching in the regular thread

and fold and press the other seam allowance around and over the trimmed one. 

You could pin it down at this stage but I usually don't. Denim can pressed really well and tends to stay in place just fine. In fact, I think having to remove pins might make your stitching more wobbly. Just stitch close to the folded edge, keeping an even distance to the first line of topstitching. 

Maybe a bit tricky if you try this for the first time but not difficult. And you get nice, strong seams and a clean, smooth inside of the garment. 

Years ago, I used a different method: I would first stitch the seam in the usual way, with the right sides facing and using regular thread. Then, I would press, trim and fold the seam allowances on the inside and then stitch along the folded edge. However, when using topstitching thread, I would have to stitch from the outside of the trouser leg, with those folded seam allowances on the inside. I made it work but that was really tricky and it involved much more re-threading of my sewing machine.
There is one area where I might try it again though: The center back seam.

Mine looks like this. I'm actually not that bothered by mismatched point but I know some people like to sew their jeans which real points.

And on the inside, that is just what I have. If I were to use my old method for flat-felled seams on the center back seam (and the regular method on the yoke seams) or even to make a fake flat-felled seam by serging and topstitching, I could have this perfect point on the outside. 
I won't try and change it on this pair of jeans though. 

Oh, and just in case you are wondering about the blue lines and the stamp on the wrong side of the fabric: This was the beginning of the bolt. I originally bought just enough for two pairs of jeans and this will be the second one. I had to be really careful with my pattern lay-out to squeeze it out of the remaining fabric so I was obviously not going to avoid those lines on the back.