Continuous Bias Binding and How to Calculate Needed Yardage. (or, Lessons from a beginning quilter – Part Deux)

Hi all, this is Kellye.  As y'all know, I’m a relatively new quilter, having only started this addiction in the summer of 2013.  I’ve done my bindings both on the bias, and straight cut…but I do prefer bias cut bindings, as I think they are stronger and will wear better.  (It that true? I don’t know…but it’s probably discussed in a book someplace.)           
           When I started this escapade, I didn’t really know how to figure out how much binding fabric I would need, or how to cut the bias binding other than cutting the middle out of a much bigger piece of fabric.  Not only did I end up buying much more fabric than I needed, but I’d have to sew all those bias strips together, end on end, AND I’d have a bunch of weird shaped leftover pieces of fabric.  Always good to have leftover pieces of fabric, but I never like the weirdly shaped pieces.  Is it just me?
           I mentioned in an earlier blog that I am a sucker for quilt books, but I tend to only look at the pictures, not read all the directions.  No surprise there, I guess, for a visual person who believes in learn by doing.  But I bought one book specifically for the text – Quilter’s Complete Guide by Marianne Fons and Liz Porter.  I bought it, honestly, because of name recognition - even I, as a neophyte quilter, recognize the names Fons and Porter! I didn’t know what ALL I would find in their book, (and I still don’t, as of course I haven’t read EVERYTHING in there) but their directions alone for calculating how much yardage is needed and making a continuous-strip bias is, for me, easily worth the purchase price of the book.  (see pages 94-95 in the book)

The basics, from Fons and Porter:
- Measure the perimeter of the quilt
- Add 15” for mitered corners and finished ends

Once you know how much bias strip you need, use this 2 step formula to figure out how much fabric you need for your binding:
Length of Strip x Width of Bias strip = area of strip
Take the Square root of the area of the strip and that will be the size of the square needed.

As an example, I am working on a King Size quilt, with dimension of 106” x 98”.  So my total perimeter is 408” to which I add the 15” extra for corners and finishing. So I need at least 423” of bias strip.
I have been using a width of 2.25” for my bindings, so 423 x 2.25 means a total area of roughly 952.   Since I don’t have a square root function on the handy "little" calculator, I just take my best guess as to inches….30?  no, 30x30 is only 900.  31” squared is 961, but that’s a little too close for me, so I’d go with a square that is 32” square, which should give me roughly 455” of 2.25 inch wide bias cut striping. (32*32 is 1024. 1024/2.25 = 455)

(Alternatively, if you have a piece of fabric, and want to know if you have enough to bind something, use this formula.  I don’t use this, as I think it’s easier to figure out what size I need for what I’m binding, and then just check that against the fabric I have.
Width of square x length of square = area of square
Area of square/width of binding strip = length of bias strip.)

The heads on the side safety pins are pointing in, while heads
 on the top and bottom are pointing out.
How to make the continuous bias strip form the fabric square.
1) Open the square of fabric flat, and mark or pin each side of the square with an indicator.  Opposite sides of the fabric should have the same marking, so you can later identify they are opposing sides.  (ie -put an X on each side, and an O on the top and the bottom.  Or put pins in the top and bottom head out, and pins in the sides head in.)

Step 3...overlapping triangles
2) Mark corner to corner diagonally, and cut the piece into 2 triangles.
3) Right sides together and with the same symbol sides matching up, pin and sew the 2 triangles together with a ¼ inch seam allowance.  You will have to overlapping triangles, hypotenuse of each running diagonally in opposite directions across the middle, one short side of each overlapping each other at the top, and a short side for each extending down in each side.
4) Open up and press seam open.  Then take a long ruler and on the wrong side of fabric, mark parallel rows of lines, spaced at the width of your binding, and in parallel to the longest (bias) edge of the piece of fabric.  Mark lines at proper spacing all the way across the fabric.  You may find the last strip you mark isn’t as wide as needed for the binding…but just keep that in mind, that the last bit of strip will NOT be able to be used for binding.
Step 4..mark the binding width. note the top of my fabric
I have a leftover strip that will not work for binding.
5) Pin together the other edges (the non-bias “ends”), right sides together. These 2 ends should have matching symbols on them or pins facing the same direction.  When pinning these ends together, offset them by 1 width of the bias strip. To get them placed properly, put a pin through the top side, ¼” down from the edge and on the line. The pin should come out on or almost on the line on the back piece of fabric.  Sew together along pinned edge and press seam open.
lining up the side edges, to make the
"tube" with binding width marked.
6) You should have a circular tube of fabric, which has on end “offset” by the width of the binding.  Start cutting there and cut up the entire piece, following the line. It should just fall off as a continuous strip as you continue to cut around the circle.
I ended up with 458” of 2.25” bias binding, out of my 32” square of fabric. 

 I loved finding this formula…no more guessing on how much I needed and no more cutting big bias sections out of the middle of the piece of fabric.  The continuous binding methodology eliminated the need to sew a bunch of shorter bias strips together, end on end, to get the full length needed.  Could be I’m the only one to whom this was new, but I’m sharing it in case there are others who also are prone to looking at pictures, not reading the text!

Now, if someone has a tip on the easiest way to join the 2 ends of the binding, after the majority of the binding is attached to the quilt.  I need tips on the best way to get the bias seam sewn in there AND getting the seam placed at the appropriate spot, so my binding is the perfect length. I’d love to get it right the first time, and not have to use my “trial and error” approach….

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