Here's a jeans repair process that help soooo many people!
It's not always glamour projects and new wardrobe in the costume studio! Favorite jeans and thunder thighs eventually lead to maintenance and repair situations. We perform quite a few of these procedures here!
I'm using my own jeans here to show you (this is Jen). And my jeans here are women's 515 Levis. The butt area fabric is worn pretty dang thin and there are already some holes in the inner thigh areas.
These repairs always remind me of making riding breeches and jodpurs with extra fabric on purpose in the seat and inner thigh, in advance of someone needing it.
First, turn the jeans inside out. Stick a tailor's ham underneath the crotch/butt area so it's elevated and you're staring straight down at it. Flatten out each area at a time, then drape and trace some muslin pattern pieces for areas that need coverage and reinforcement. You can create your pattern piece's mirror-image by folding the muslin in half, then cut.
Keep your new patch pieces as flat as you can, as well as the jeans' crotch area.
Be thrifty. Make your patches from legs of other recycled jeans that are a good color/texture match.
Below, I've already cut my first patch piece from recycled black denim and have glued it in place. I used barge cement because it was on the table and handy. Almost any fabric glue will work. If you glue your pieces, it's easier to stitch them on than if you've pinned them. Put some weights on them and let them set and dry before sew.
To reinforce this butt area I'm making two of these pieces and I'm avoiding the jeans' existing flat-felled seam areas here so the layers won't be too bulky for my sewing machine.
You can feel the seams underneath the areas you're tracing. You get better results with multiple pattern pieces. They'll lay flatter and you'll achieve a better overall result. A pants crotch/butt is a curvy area and there's no way to do this with just one pattern piece!
Below: All my patch pieces are cut out and glued down. You can see my chalk lines defining the shape and borders. I'm attempting perfect butt symmetry here.
Now get your free-arm sewing machine threaded up in a matching color and stitch your patches on. Keep all your fabrics flat and pucker-free. It's why you are applying two or more patches rather than one big patch.
I straight-stitched them on, then went around a few times with a zig zag stitch. I want the patch edges to not curl up or fray. If your machine has a low gear like this great old Viking does, use your low gear in the bulkiest areas for more control, power and less chance of needle breakage.
Enjoy your repaired, reinforced jeans! This process is good for those old favorites where you (or your client) don't mind a bit of frankenstein-ing.
I've had these jeans for years and they've already been through some previous alterations. I lowered the back pockets (which were too high on the booty) plus shortened and tapered the legs (which were too long and too wide).
When I removed my jeans' back pockets to reattach them, I did this when they were new, so it's almost impossible to see the previous stitching marks.
When it comes to jeans, women seem to be pretty picky about what works for us and what doesn't. I think it's a universal refusal to unquestioningly accept whatever manufacturers put out there!
Maybe sometime in the future I'll re-dye these jeans with some nice, intense intense fiber-reactive dye. That'll get them nice and black again like when they were new!