I had hard time soldering DIP pin legs to conductive fabric. It becomes always crumbly and does not stick to the fabric good. (Also I am using lead free solder, that makes it look crumbly too)
Nadya Peek gave me a nice tip to use “more Flux”.. so I tried with Flux Pen and Flussmittel (bottled liquid).
The result is “ok”, not perfect but with practice it will get better. Here is some pictures.
conductive fabric used here are Flectron N from LessEMF, and strips are 1mm/1.5mm/2mm/3mm from top
detail of the wire/fabric connection. Flussmittel makes a brown stain, and it is not suitable for use on light color fabric. I have not tried to wash it to see if it comes out with washing.
Test on soldering DIP pin legs to conductive fabric. Right side is with Flux Pen. It is much easier to solder with flux than soldering without (left side)
Instead of soldering, you should try conductive epoxy or other conductive adhesives and even some conductive inks might work.