Today, we are going “back to basics”! We will be talking about how to piece long strips together using a diagonal seam. Most often, we piece strips together for binding- because you need a looooooong continuous strip of fabric to go around all the edges of your quilt. However, you can also use this method for piecing together strips for quilt borders. If the side of your quilt is more than about 41″ long, you have 2 options: you can piece together strips which have been cut across the width of the fabric (from selvedge to selvedge, which is about 40-42″ for most quilting cottons) OR you can purchase enough fabric to cut one long continuous border along the length of the fabric (parallel to the selvedge.) While cutting the border parallel to the fabric selvedge means that there is no piecing involved, it results in a lot of leftover fabric! So, I always piece my borders.
For binding, using a diagonal seam has the bonus of distributing the bulk of the seam allowances, so you don’t end up with a big lump in your binding where you pieced your strips together.
A diagonal seam is less noticeable than a straight seam. The only time I don’t use diagonal seam is for striped fabric- the seam is much less noticeable if you just do a straight seam. You could do a diagonal seam and try to get your stripes aligned- but why bother? LOL. Notice in the photo below, that the strip with the straight seam (on the left) looks much better and less noticeable than the one with the diagonal seam (on the right)- even though the stripe repeat isn’t exactly lined up in the photo on the left.
So here is how I piece fabric strips with diagonal seams:
Cut the strips from the width of the fabric (selvedge to selvedge), adding 1/2″ to the desired border width. So, for example, if you want your borders to be 4″ wide in your finished quilt, cut them 4 1/2″ wide. (You can leave the selvedges on for now, we will trim them later.)
Your cutting mat, with measurement grid, is your best friend for this process! Place a fabric strip on the mat RIGHT SIDE UP, with the edge of fabric lined up on one of the horizontal cutting lines.
Now place another strip, WRONG SIDE UP, on top of the first strip (so the 2 strips are now Right Sides Together), and line it up along one of the vertical cutting lines. Let those selvedges hang over the edges a bit.
To keep the strips from falling off the table or slipping out of place, I sometimes place something heavy on them to hold them down. (I put the weights on the ends of the strips, out of the way.)
Use a straight edge to draw a line from corner to corner where the strips overlap- you will be drawing a line with a 45 degree angle.
Carefully pin the strips together, making sure that the fabrics are still lined up on the cutting mat lines. I like to set my pins back away from the line, so they don’t get in the way while I’m sewing. Make sure that you pin well- due to the weight of those long strips, it’s very easy for them to wiggle out of place! It is crucial that the strips are perfectly perpendicular to each other (90 degree angle).
Sew on the line.
Open up the strip to make sure that it is straight and that the edges of the two strips are well aligned at the seam.
Trim away the excess fabric, including the selvedges and little “dog ears.” Be sure to leave a 1/4″ seam allowance for borders, and about 3/8″ for binding.
For borders, press the seam allowance to one side. For binding, press the seam open (this will result in less bulk at the area of your seam in the binding.)
Piece together as many strips as you need until you get the required length. For borders, cut to the correct length after you’ve pieced them together.
That’s it! Easy peasy, right?