Pennyhal

I can't lower the pressure on my machine either. It has "automatic" pressure supposedly. I prefer being able to set the pressure myself.

Kwiltr

You do need to be careful with how 'taut' you spread your backing out. If you put too much tension on it so that you are actually stretching it, when you remove the tape or clamps that you have used to do this, the fabric will recoil back to relax and your top will have been spread over an area too small for it suddenly, if you get my drift.. Also, when you use spray basting, like 505, Ann Peterson recommends ironing the quilt after it's spray basted to set the adhesive. So that's how I do it and haven't had any problems. I'm working on a 100 x 116" quilt and the only small puckers I had in the top were where my piecing was less than optimum and the quilt is a heavily pieced In HST's and 4 patches. I ditched it on my Janome 6600 with a walking foot.

Bree123

If you are using a FMQ (darning) foot rather than a walking foot, you can adjust the pressure by wrapping an elastic band around the top of the post -- push down on the spring a bit first. I have found I can actually get better straight line results with a darning foot than with a walking foot on my machine -- a 1975 Singer Genie.

The other thing I have found that helps if I do use a walking foot is to alternate between sewing horizontal & vertical lines. That way the bunches are pushed out to the corners rather than popping up at the intersections. Also, I know it's a big "no-no" in the quilting world, but sometimes I will pull behind & in front of the walking foot. Apparently, on some machines that will cause slipped or loose stitches, but I don't have that issue & it helps to compensate for some of the QC issues I have using a modern generic walking foot with my "vintage" machine.

illinois

I haven't used the spray basting so don't know if my "method" works with that but, when I'm approaching a previously stitched line, I pull the quilt just a bit and that seems to ease everything better. It lets me avoid the puckers that I think you describe.

EmiliasNana

When I spray baste I use painters tape to tape the backing to our ping pong table. I don't stretch it but make sure it is taut enough so that when I run my hand across it, it doesn't bubble. Then I smooth my batting on top without spraying anything. Using a board that is slightly wider than my quilt, I start at the narrowest edge, and roll up the batting half way, flipping the board and wrapping the batting around it as I go. Then I spray.........either the batting as I unroll, or the backing fabric. Unroll the batting and repeat on the other side. I never get any wrinkles or bubbles. Next, position the top on the batting in the position desired. Repeat, only this time roll the top onto the board and spray the batting. Everything stays straight and wrinkle free. Works for me. Once I am done, I release the painters tape and using straight pins, pin all around the edge of the top, through all three layers. When I get back to my sewing machine I baste around the entire edge with my walking foot to hold the three layers together while I FMQ. Sometimes I press all three layers together, sometimes not, before I begin. Good luck and hope this helps.