Glad your first time is working out for you Alice. It's a wonderfully
useful technique.
I have tried joining with paper on, and off. Here is what I have found:

the paper stabilises everything beautifully, so if you have triangles,
with -therefore- bias edges, I would leave the paper on.
It is very difficult to match seams etc with the paper on, because the
feed dogs can't grip on the paper.
So, what I have now decided to do, when I want to leave the paper on,
is: to draw my patterns *without* the outside seam allowance included.
You can still trim accurately, because you line up your ruler's quarter
inch mark with the edge of the paper. But, you have a fabric seam
allowance which can be pinned (keeping the pinned piece tiny, within the
seam allowance - I 'click' the paper edge with my pin point underneath
and then bring it up through the fabric. One set of feed dogs is under
fabric, so that helps.

On the other hand, if my edges are not bias, I will usually press
carefully, trim and then remove the papers.

A quarter inch binding will be fine for 12" x 12".
..
In message , Alice
writes
I'm trying a paper piecing project for the first time. I won a "Tin Box
Sampler Series" of gorgeous crackle charm fabrics as a door prize. There are
very minimal directions with it to make nine Courthouse Steps blocks. I
figured out the cutting, and construction, but now I have a couple
questions. On the paper foundation pieces there are TRIM lines and SEAM
lines. It seems that I would trim the blocks with the paper still attached
so I can follow the lines. Do I also stitch the blocks together with the
paper still on? Do I trim and then remove the paper? Also, since this
project ends up being 12" X 12" what size binding do I use....narrower than
for a standard sized quilt? Thanks for any help.

Alice in PA



--
Best Regards
pat on the hill