I am going to attempt to SID a wall hanging. I've never done machine quilting before. Besides spray basting, do I also have to pin the quilt before I sew? TIA

I have never found spray basting strong enough for holding a crib size sandwich let alone anything larger. I hope you have better luck than me. What size are you doing?

I don't.
Once upon a time, all my quilt sandwiches were pinned, but now I've discovered spray basting and said good-bye to the pins.
My quilts are stitched on a home machine, so there's lots of rolling and stuffing going on, and they haven't come apart yet.

I do a little of both...I spray, then I pin in spots where it is very important that I have no shifting. Then I do some strategic "stitch in the ditch" if I'm using that...then I remove all the pins and just rely on the spray. I haven't had any problems..but I use the 505..I think it holds better.

I must be using the wrong stuff , what brand of spray do you use?

I did my first machine quilted project this week using the spray baste (hate to pin and baste)...it was ok - but I did have a few wrinkles that got caught in the sewing near the borders and outside corners. I think the edges just got handled more and didn't stay as secure. The middle was good tho.... Another reason maybe is that I was a little hesitant to over-spray the baster and just kind of closed my eyes and did a pass-by over the batting, LOL. I think next time I will spray better, but i will use a few pins on the edge - at least until I am more experienced...

When the Chinese Coin wall hanging is done, it will be 42x50. I will use 505. Do I start SID in the center or at the top of the quilt?

I love the 505 spray! It held my last project together perfectly with only 1 large pin in each corner...

I trained hubby on how to spray it and using a respirator while doing it...because I cannot spray right now due to pregnancy.

I started in the middle and did small bursts across from right to left working my way down to the bottom of the quilt, flipped it around and did the same again until I reached the edge.

I spray baste and throw some pins around the edges only.

I try starting the SID in the center and work out whenever possible. :D:D:D

Thanks, I appreciate the feedback.