Pressing is an important part of the piecing process. Pressing can make the difference between a flat block with perfect intersections or one where all the seams look slightly off.
One of the most important things to remember when pressing for quilt making is that you should never just put the iron down and slide it around at random. When pressing uncut pieces of fabric, iron with the grain, either from selvage to selvage or from one cut edge to the other. Never iron in a circular motion. You will be distorting the threads in the fabric and will make it harder to cut your pieces on the grain.
At Quilt University, we strongly recommend that you prewash all your fabric. There are several important reasons for doing this:
Formaldehyde can cause severe respiratory illness, especially if you are exposed over a long period of time. A large stash of unwashed fabric will be emitting formaldehyde fumes in your house. Once your lungs are damaged by this chemical, they cannot be repaired.
Fabric should be washed with a small amount of bleach-free detergent on the gentle cycle. Use the temperature you plan to use when washing the quilt. Dry on permanent press and do not over dry. Take the fabric out of the dryer while still warm and smooth with hands to fold. No ironing is needed if you are planning to store the fabric for future use.
Washing removes the sizing used by the manufacturer. In some cases, the fabric is then revealed to be of poor quality and you should consider discarding it. In most cases, this will just mean that light colored fabrics are soft and stretch easily. We recommend that for all white or light colored fabrics, you press the fabric with spray sizing or starch before you begin cutting. You should NOT do this when simply storing washed fabrics. Do it right before you plan to use it. Remember to press with the grain of the fabric.
Sizing is an artificial starch. Starch can attract bugs in warm humid climates. Both products are usually available in the laundry aisle of the supermarket.
Using steam all the time can distort the shape of your cut shapes and pieced units. An iron set on cotton should be hot enough for most seams. If you need a boost of power for a thick seam allowance or a stubborn wrinkle, use a spray bottle and apply a quick squirt of water to the needed area. Wait about 30 seconds for the water to penetrate the fibers and then set the iron down. The problem area will be taken care of but you will avoid the dangers of dampening the entire piece and steaming it.
Using the spray bottle is especially useful when you want to press seams open. Start by opening the seams with your fingers and finger pressing gently. Spray the open seam with a little bit of water and wait for the fabric to absorb the moisture. You can now use the point of your iron along the seam line to open it fully and press it flat. When the seams are pressed, turn the block over and set the iron down briefly to complete the pressing. This is one of the few times where you will press from the back.
For most seams, you should press from the front, lift the fabric on the seam farthest from you as you press. This makes the seam go to the side you are lifting and eliminates any possibility of creating a pleat at the seam line. It is easy to get those little pleats if you press from the wrong side.
Many quilt patterns start with strips. If you have two strips cut the full width of your fabric and are sewing them together, you do not need to pin. Just be sure to keep the cut edges lined up as you sew. Never pull on either end of the strips. Fabrics will be slightly different widths, making the strips different lengths.
Correct tension while sewing is essential. If the tension is too tight, you will get a slight pulling in the stitches and the sewn strips will bow. Bowing can also be caused by incorrect pressing.
Take your sewn strip set to the ironing board. Lay it down with the dark strip on top and set the iron down on the sewn stitches with the strips still right sides together. This sets the stitches into the fabric. Regardless of what two shapes you are sewing together, you should take a second to set the stitches.
Press stitches in place before opening the strip set
Use tip of iron to press open from the center of the strip set
To open the strip set, lift the top piece with your hand. Start in the center with the tip of your iron and press to one end. Then start in the center again and press to the other end. Since you have your dark strip on top, the seam allowance will be pressed to the dark side. Sewing from the middle to each end prevents the strip from bowing out or curving. If you need to press to the light side, start with that strip on top.
If you are making a Rail Fence or other block which requires more strips, you can
For this sample, I am going to work with a single strip set and cut it apart to make 4-patch units. My strips were each 1 1/2" wide. That gives me a 2 1/2" strip set. To make a 4-patch, I will cut segments that are the same size as my original single strip - 1 1/2". When two of these segments are sewn together, the unit will be 2 1/2" square. When cutting segments, be sure that your ruler remains perpendicular to the top of the strip set. Check for accuracy frequently.
A 4-patch can be made with the seams pressed to one side or with one or both of the seams pressed open. Think ahead about how you are going to be using your unit. As you put blocks and rows together, you want seams to face in opposite directions as they meet at intersections. Below left, you can see that the seams face in opposite directions. On the front, shown in the picture at right, the join is perfect. The second 4-patch started with the same segments, which already had the seam allowance pressed to one side. After sewing the two units together, the new seam was pressed open. An open seam can be helpful if several seams will be coming together at the same place.
The back of the two 4-patch units shows seams pressed two different ways. The fronts, shown at right, show that there is no difference on the surface.
The disadvantage of pressing open is that the fabric can pull apart at the seams, allowing batting to migrate out of the quilt. You should never stitch in the ditch if you have pressed your seams open.
Flying Geese are made of three triangles. That means that you will be sewing on at least one bias edge. It is a good idea to treat both light and dark fabrics with spray sizing before cutting them out for this unit. The extra stiffness will help prevent stretching and distortion.
In general, FG units are cut so that the small triangles (sky) have the bias on the long side that is sewn to the middle triangle while the big triangle (goose) has the bias on the long edge at the bottom. That means that you will NOT be sewing two bias edges together. This is an important consideration.
Place the first sky triangle against the goose with the bottom edges even. Stitch and press open with your fingers. Avoiding the iron at this point will minimize stretching.
Sew first triangle and finger press open
Sew second triangle and press open with iron
Place the second sky triangle against the goose, keeping the raw edges even on the long side AND on the bottom. Stitch, set the seam with the iron and press open.
The main consideration in an FG unit is the point at the center of the top. No matter where you trim the sides, the bottom will still form a point when you sew it to an adjacent unit. The top MUST have a 1/4" between the point and the raw edge or the point will be lost in the seam allowance.
Squaring up this unit is essential. Start with the top and left side. The picture shows the unit side to side but you would have the point on your right or dominant side. The point is the exact middle of the block and should be the midpoint on your ruler. The FG below is being squared to 6 1/2" so the midpoint is 3 1/4". You also want the edge of the ruler to be 1/4" away from the point. Trim off anything that sticks out beyond the ruler on the top and left side.
Lining up the ruler to square of a flying geese unit
Rotate the block, line up the ruler on the two previously cut edges and trim the bottom and right sides of the unit. The trimmed front and back are shown below.
Front and back of finished FG unit
For most traditional quilts, you want to sew and press small units together first. Half squares and Flying Geese units are examples of units that are completed before you assemble the block.
In the star block below, there is a small friendship star inside of a large variable star. The order of construction would be:
Friendship star completed (left) and laid out for sewing (r)
The picture at right above shows that units that are assembled before you lay out the rows. The plus signs indicate which pieces will be joined and the arrows in red show the direction the seams should be pressed. I always begin in the lower right hand corner and turn my pieces right over left. Doing it the same way every time means that I can always tell where I am. I can chain piece the first three pairs and then replace those on the layout and complete sewing the rows.
When the rows are completed and the seams pressed, the three rows are joined to complete the block.
If all your blocks are the same, as they are in the layout below, you can alternate the direction in which you press in the blocks the seams so they will butt correctly when you sew the rows together. If you do not like to spend a lot of time planning in advance, just be sure to pin the seams facing in opposing directions and sew them carefully. It is okay to have one end of a seam facing left while the other end faces right. There will be a place in the middle of the seam where there is a small twist. This will be buried in the batting and will not show from the front.
Back view of pressed seams
When assembling the rows, it often helps to pin paper arrows on your design wall. This will help you remember which rows will have seams pressed up and which have seams pressed down. It is also a good idea to pin the top block of each column so you can easily tell the top from the bottom.
Paper arrows on design wall help you remember which way to press each column