Love the look of denim but hate sewing with it? The best way to overcome problems is to address them before you begin. Read on for great tips and tricks to help overcome denim sewing problems.
Let’s Talk About Weight
Denim is a great fabric – durable, comfortable, and available in many weights, colors, and designs. The key to a great denim project is choosing the right fabric.
Make sure the weight of the fabric you select is a good match for the project you are making. Generally, a tote bag, purse, jeans, skirt, or jacket work much better with a heavyweight denim. The weight will help a garment hug the body and a bag hold its shape.
If you are making a dress or blouse, select a lightweight denim so the fabric will feel comfortable when moving and hang softly at the hemline.
Here’s the deal: You must NEVER begin sewing with denim before you preshrink the fabric.
You might be wondering: What is “preshrinking”? Basically, it’s washing and drying the fabric before cutting into it. Preshrinking removes the heavy chemicals and glues used in the milling process. Removing foreign material before sewing avoids frustration and broken needles.
Four keys to successfully preshrinking denim:
- If you own a serger, serge around the four sides of the fabric before putting it in the washing machine. If you don’t own a serger, no worries. You can accomplish the same thing by folding and ironing a 1/4” hem and sewing all the way around the length of fabric. This will secure your fabric so it doesn’t ravel and will hold its shape through machine washing and drying.
- Wash twice to ensure all chemicals are removed.
- Preshrink your fabric by itself or with other dark blue items so your whites don’t come out light blue.
- Soaking the fabric overnight in warm water and a cup of white vinegar will help remove excess dye. Follow up by washing and drying the next morning.
After preshrinking, denim will sew better and will no longer shrink or lose color.
Layout and Cutting
Stay On the Line
Heavy fabrics tend to twist after sewing if you do not cut on the grain of the fabric. Be sure the long line on each pattern piece labeled “grainline” is exactly parallel to the straight edge of the fabric. Do this by poking a straight pin through the pattern and fabric at one end of the grain line to hold the pattern in place.
Now, measure from the pin to the edge of the fabric. Place a second pin similarly through the other end of the grain line and, again, measure from the pin to the edge of the fabric. If the measurements are the same, you are aligned on the grain. If they do not, adjust the pattern at one of the pins until the measurements are equal.
To assure the pattern doesn’t move while you’re pinning, secure the two pins in place and remeasure. Finish by pinning the remaining pattern to the fabric.
The Sharper, The Better
I personally never use scissors to cut out a pattern. Instead, I use a self-healing mat and a rotary cutter. Rotary blades are much thinner and sharper than scissor blades, and you do not have to lift the fabric and risk moving it to get the scissors underneath.
I find rotary cutting not only faster but much more accurate. A 45 mm blade is best for thick fabrics, like denim, while a smaller 28 mm blade works well for fine materials.
Whatever tools you select to cut denim, make sure they are very sharp. Change the blade in your rotary cutter before proceeding or have your scissors sharpened.
It’s Not How You Start, But How You Finish That Counts
This might seem crazy, but it’s true: Fabrics can fray right out of the stitches. When they do, the seam comes apart. Choose one of the following fabric finishes to prevent this problem:
- Serge the Seams. If you own a serger, you may sew the seam and serge it closed at the same time. This leaves a double layer of fabric serged together.
- Serge the Fabric Edges and then Sew the Seams. Because raveling is so common with denim, it is recommended that you finish the edge as soon as you cut the pattern pieces out. With this technique, serge all the way around each pattern piece before you begin putting the pieces together.
- Welt Seams. A welt seam begins with a 1/2” serged seam (See #1 above). When you finish serging the seam, press the seam to one side. On the right side of the fabric, sew a 1/2” straight stitch parallel to the seam and along the outside edge of the serged seam on the underside of the fabric. (Hint: I “sew with my fingers,” meaning, I run my finger along the stitches to be sure I am catching the edge of the seam on the underside. You can feel the “drop-off” where the seam allowance ends on the underside.)
- Flat Felled Seams. This technique should be considered if you don’t own a serger. Sew a 5/8” seam. Cut one of the two seam allowances in half, leaving the second seam allowance 5/8”. Fold the 5/8” seam allowance in half over the edge of the seam allowance you just cut in half, forming a casing over the raw edge of the shorter side. Press the folded seam allowance to the side so the raw edges are enclosed between the inside of the fabric and the seam allowance. Sew parallel to the seam and right on the folded edge of the seam allowance.
Because denim seams are so thick, you can break a needle quite easily. Help prevent that by using needles made specifically for heavy fabrics. Schmetz, a leading maker of sewing needles, makes needles called Jeans needles. A Singer heavy-duty needle will also work for denim fabric. Finally, Tacony also makes a Jeans needle.
Another way to protect against broken needles is to use a walking foot. This bulky looking foot is designed for quilters who have to make intricate designs through two layers of fabric plus a thick batting. As the name implies, the “walking foot” has two feet that move forward one at a time. The twin feet raise the walking foot up off the fabric.
This foot can be especially helpful when you are crossing the intersection of two seams (like the crotch of a pair of pants). If you feel any binding, even using a walking foot, stop using the foot pedal and turn the flywheel by hand until you cross over the seam. You then control the needle as you press down through multiple layers of fabric.
There is also a tool called the Bulky Seam Aid you can place over the bulky double seam to help “walk” over it; beware, however – you may still need to slow way down and hand-turn the flywheel to prevent broken needles.
Check this out! Another needle-threatening situation comes as you start sewing a seam. The sewing foot is naturally forced up in the front and down in the back because of the thickness of the fabric. This slant may cause the needle to enter on a slant as well, ending with that dreaded “bang” as another needle bites the dust.
Dritz has created the Jean-a-ma-Jig for just this application. Place the Jean-a-ma-Jig behind and under the foot to raise the back of the sewing foot to the same level as the front.
Denim Sewing Tips
Heavy-duty thread should be used when sewing heavyweight denim. Like needles, you can find a thread specifically designed for sewing on denim in most sewing stores.
Stretch it Out
Stitch Length = 3.5 or longer
Normal stitch length is between 2.5 and 3.0; however, when using heavyweight fabrics, you should lengthen that stitch length to 3.5 or even 4.0. To determine the proper setting for your sewing machine, using two small scrap pieces of your fabric, sew a seam, press it open, and then look at the seam from the right side of the fabric. Lift the seam up toward a light and see if you can see gaps between the stitches. If you can, shorten the stitch length a little. If you see puckers and pulling between stitches, lengthen the stitch.
Don’t Forget the Tails!
Be sure to pull the thread tails to the back of the presser foot, and hold both of them as you begin sewing. It is not unusual for needles to come unthreaded because the thread tails are too short and pull out while you lower the presser foot.
Denim is often highlighted with single or double rows of topstitching. Sometimes they use a color that matches the fabric. But for fun, you might like to try using a brightly colored textured thread or one of many decorative threads that are available in today’s sewing stores.
While metallic threads are beautiful and shiny, they are difficult to sew with. If you choose metallic, be sure to change to a metallic needle. The problem you may run into is, I have been unable to find a heavy-duty metallic needle, and you may find metallic needles break easily. If you use a heavy needle that isn’t made for metallic threads, the thread may break frequently.
Two additional choices for decorative threads are poly and rayon threads. They come in every color in the rainbow and are very shiny. Another option is variegated thread, available in many color combinations as well.
A second benefit to topstitching is the second row of stitching provides additional strength to the seams.
Get a Clapper
As with all sewing, and even more important on denim, use a steam iron at a high temperature to press seams as you sew. A tailor’s clapper is a special tool designed to make sharp, crisp seams. This wooden tool is pressed down on a seam after steam pressing while the fabric is still hot and damp. Apply pressure until the seam cools.
The final touches to your project also need to match the weight of your fabric. If you used heavyweight denim, use heavyweight zippers and fasteners. If you use lightweight denim, regular weight zippers and fasteners will be fine.
That’s All Folks!