Here is the invisible zip that we used in the sunvisors. This is actually a dress zip purchased from Lincraft. Laurel figured it only had to be done up once, so it was better to use an invisible zip rather than a heavy upholstery zip which would have been highly visible.
After cutting out the fabric for the sunvisors, we installed the zip along the pivot edge (closer to the windscreen) and down the side. This meant that the remainder of the sunvisor fabric could be sewn and then the zipper opening was used to insert the visor.
Laurel used double sided basting tape to temporarily hold the zipper to the fabric and to hold the seams together before sewing. (More on this at the end of this post.)
After inserting the zip the two pieces of fabric were sewn together along their remaining sides leaving an opening for the post to be inserted.
To get the cover to sit flat around the edges, it's important to clip all the convex curves by cutting a number of small 'V's from the seam and the one concave curve just needs to be snipped in a few places. That way the fabric doesn't bunch up on the curves when it's turned inside-out and the concave curve is smooth.
The finished and installed sunvisors. It was quite traumatic cutting the holes in the headlining for the spring part of the sunvisor post to poke through.
...and folded down.
A note on what was important when sewing this upholstery:
All the upholstery was sewn on my domestic Bernina Aurora 430. When I bought it, everyone told me that a "walking foot" was essential for the job. I had never used one and didn't think it was necessary, but they were right. A walking foot effectively lifts the foot off the fabric between stitches so the top fabric does not move in relation to the bottom fabric while you sew.
The other thing which I only discovered recently (in time for sewing the sunvisors) is double-sided basting tape. This would have made the rest of the upholstery in the car soooo much easier.
silver pieces on each seat), they still tended to move when you sew. With the basting tape (1/8 th inch wide), you just run a narrow strip down the seam allowance and peel off the paper backing.
Then stick the other piece of fabric to it. Hey presto, they don't move a bit. When you're finished, you just pull the seam allowances apart and pull off the tape. It's truly the most fantastic sewing notion I've ever found. It costs $1.95 for 200 inches and is available in Australia from "Punch With Judy".