T-40 spun polyester is a strong thread for industrial straight stitch machines. I use it to sew all of my slipcovers no matter the fabric. I keep basic colors on hand: white, antique cream, khaki, dark grey, black and dark navy.
T-27 spun polyester thread is the one I use on my 2-needle, 4-thread industrial serger. This is a strong, quality thread that works great for overlocking seams on all types of slipcover fabrics.
This is a wholesale resource for medium-firm welt cord. It has a poly tissue-like core and wrapped with a poly braided cover. It’s firm enough to keep its shape yet soft enough to bend around curves smoothly.
Doesn’t shrink or pucker when slipcover is washed under normal conditions. The 5/32 size is standard for slipcovers. A smaller size 4/32 is also available.
Below is a retail resource for DIY slipcover makers. Same cord as described above. Buy exactly the amount you need for your project.
Wholesale resource for size 4.5 nylon coil zipper tape in 215 yard rolls and matching slides. This is what I use for sofa and armchair cushion covers. Strong and flexible. I keep 4 colors on hand: White, Tan, Black and Grey.
Retail source for nylon coil,closed-end zippers. I keep 2 lengths of size #3 on hand in colors white, natural, tan, black and grey: 30” long for side entry on the slipcover body and 24” long for throw pillows. I cut them shorter when needed.