Thursday, August 22, 2013

Triangle tips and inspiration

So, this triangle quilt came about because when I was at the Ann Arbor Modern Quilt Guild retreat this summer, finishing up my scrappy trip along, basting my drunkard's daisy quilt, and beginning to piece the Lotta Jansdotter quilt, Emily was piecing this beauty.

In the meantime, I have noticed many amazing equilateral triangle quilts appear on blogs and on instagram (Emily made another, too, and it's only been, what? 6 weeks since the retreat?)

In case it's becoming a thing, I am going to present my thoughts on it here.


The triangles shrink left to right when you sew them together, but only lose 1/4" height top to bottom. And when you join rows (losing 3/4" total).

Mine are 7.5" high (which makes the sides 8 2/3" each - based on geometry), and I went with 18/row and 13 rows - which is a little over 6 feet wide, and 7.3 feet tall.

How many should you cut? Well, what kind of quilt do you want? How about an equation? 

quilt length = row # x (triangle height - 0.75)

-Or, if you prefer not to do the algebra- triangle height = quilt length/row # + 0.75

(The 0.75 is your seam allowances - 0.25" lost in row piecing + 0.5" lost in row joining.)

So, if you wanted a baby quilt, which to me is 3' x 4', and thought 8 rows would be cute, you would write down:

triangle height = 48"/8 + 0.75 = 6.75"

Half an equilateral triangle 6.75" high is a right triangle, and you can solve for the long side using geometry:  

side length = 2*height /  3 

in our example:  side length = 2 * 6.75" / 1.732 = 7.8"

So, to find out how many triangle in a row, you actually have to figure out how many pairs, because the upper half of a triangle is tiny, while its base is huge, but they average out if you pair them:

number of triangle pairs = quilt width / (triangle side length - 0.5)

(The 0.5 is your seam allowances, again.)

number of triangle pairs = 36" / (7.8"-.5") .... roughly 5 pairs, so about 10 triangles/ row, or 80 triangles for this 8 row quilt.

*alternately, if you want to solve for the number of triangles, you can use:

number of triangles = 2 * quilt width/ (triangle side length - 0.5)

I decided to use patterns from some of my Spoonflower fabrics for the demos.
Cut your height first! And then use the 60 degree guide on your ruler to cut the triangles (if you need more details, Faith from Fresh Lemons has a great tutorial on this). In a 22" wide cut, you can get 3-4 7.5" high triangles - 18", only three, and 7 in 44" one. (At least that was my experience.)

You want to have your triangle height running along the grain of the fabric, either the crosswise or the lengthwise grain is fine - depending either on convenience or on the pattern of the fabric. But the bottom side should be aligned on the grain, because, well, it is a triangle, and triangle edges are notoriously stretchy except where they run along the grain.

You'll notice that I didn't start my triangle cuts right at the edge, but left a margin. That is so I can save those pieces for row ends. However, you need not do this for every fabric you cut - with 60 fabrics, I could have up to 120 of these end caps, but with only 13 rows, I only need 26.  (Although, one must note that unless you are using only solids, they are chiral; not every end cap will fit on every triangle.  And it becomes even worse if the fabric is directional.)


step 1: make sure the grain is going in the right direction!
The first blocks are easy, just line up the points and sew. Press the seams, then pick up another triangle.

You may be thinking that this is a good time to chain piece- well, don't. Your best chance to line up triangles (unless you have clipped all of them) is to leave a corner free. On that note, I found it helpful not to clip dog ears, too.

Line up your new triangle with free corner and the folded under dog ear.
Although I did chain piece them in a fashion - I started all the rows at once! I sewed 13 triangles to 13 rows, then pressed them open, then started over.

And when the row is finished, I still don't trim the dog ears, but use them for a guide to line the row up with its neighbor:
These seams do get very bulky, though.
This is a fairly quick and dirty way of powering through triangle piecing. If you want a more elegant approach, I would suggest this tutorial from Adrianne at On the Windy Side.

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