How to Sew an Insulated Lunch Box

If you take the time to pack a lunch, you don’t want it to spoil before you get a chance to eat it. Making your own insulated lunch bag ensures that your food will stay cool or warm since there’s a layer of insulated fleece between the fabric layers. You can customize the fabric so your lunch bag reflects your personal style. Since you do have to sew through several layers, you’ll need a sewing machine and intermediate sewing skills to complete this fun project.

1. Cut 2 13 in × 16 in (33 cm × 41 cm) pieces of cotton fabric for the outside of the bag. Buy ¹⁄₂ yard (0.46 m) of cotton quilting fabric for the outer layer of your bag. Choose fabric that matches your style if you’ll be using the bag yourself or let your child pick out the fabric if they’ll be taking it to school. Then, cut 2 pieces that are each 13 by 16 inches (33 cm × 41 cm)
2. Cut 2 13 in × 16 in (33 cm × 41 cm) pieces of insulation fleece and lay them flat. Get ¹⁄₂ yard (0.46 m) of insulation fleece and cut out 2 pieces that each measure 13 by 16 inches (33 cm × 41 cm). Then, lay the pieces shiny side down on your work surface. These insulation pieces will go in between the lining and outer fabric to keep your food cool or warm.
3. Spray the wrong side of each cotton piece. Flip each of the decorative rectangles so the pattern side faces down. Then, take a can of fabric spray adhesive and spray it over the wrong sides of the cotton fabric.
4. Press the adhesive-coated cotton onto the insulation piece. Lay the insulation fleece pieces on your workspace so the shiny side faces down. Then, put the coated side of the cotton piece an insulation piece and line up the edges. Smooth the wrinkles of the fabric with your hand and repeat this for the other piece.
5. Sew a diagonal line of straight stitches across a corner. Position your needle a few inches away from a corner of the fabric piece. Sew a diagonal line to the side that’s perpendicular to your starting point.
6. Make parallel diagonal lines across the entire fabric piece. Put your needle about 2 inches (5.1 cm) from where you originally started sewing. Sew another straight diagonal line that’s parallel to the first line you made. Then, keep moving your needle over by 2 inches (5.1 cm) and sew parallel lines until you’ve quilted across the whole surface.
7. Turn the fabric 90-degrees and sew diagonal lines to make a diamond pattern. To finish quilting the piece, turn the fabric 90-degrees and put your needle a few inches from the corner. Again, sew straight stitches in a straight line from 1 side to the next side. As you sew parallel lines across the surface, you’ll see the lines form diamond shapes.
8. Trim each quilted piece to a 15 ¹⁄₂ in × 12 ¹⁄₂ in (39 cm × 32 cm) rectangle. Lay 1 of your quilted pieces on a cutting mat and use a rotary cutter to trim ¹⁄₂ inch (1.3 cm) off of each side. This removes bits of insulation fleece that might be sticking out from the edges. Repeat this for the other quilted piece.
9. Mark 2 inches (5.1 cm) from the top corners with a fabric pen. Lay your quilted pieces flat and place a ruler along the top edge. Measure 2 inches (5.1 cm) down from the top and 2 inches (5.1 cm) from the side. Make a mark with a fabric marker so you know where to position the Velcro. Repeat this for the other side and for the other quilted fabric piece.
10. Stick 2 pieces of Velcro near the top corners of each quilted piece. Unpeel 2 1 inch (2.5 cm) pieces of sticky back Velcro and place the hook sides on 1 piece of fabric. Position them vertically on the marks. Place the loop sides on the other piece of fabric so they line up.
11. Sew the Velcro to the quilted pieces and set them aside. Use your sewing machine to make small stitches through the Velcro. Sew around the sides of each Velcro piece so they’re securely attached to the quilted pieces. Then, put the pieces aside while you work on the inner lining pieces.
12. Stack the outer pieces so the right sides touch and sew along 3 sides. Take a quilted outer piece and lay it so the pattern faces up and the Velcro is near the top. Lay the other quilted piece on it so the pattern sides touch and the Velcro pieces stick together. Then, use a straight stitch to sew down each of the long sides and across the bottom, which doesn’t have the Velcro.
13. Fold the bag in half and draw a straight line across each corner. Take the inner liner of the bag and fold it in half so the seam runs across the middle. Place a ruler 2 ¹⁄₂ inches (6.4 cm) from the corner point and draw a straight line so it’s perpendicular to the corner. Repeat this for the other side of the bag.
14. Straight stitch across the corner lines and trim off the excess fabric. To square off the bottom of your lunch bag, take your fabric to the sewing machine and sew a straight line across the line you marked. Repeat this for the other corner of the bag. Then, use your rotary cutter to cut off the excess fabric from each corner.
15. Cut 2 inner lining pieces that are each 15 ¹⁄₂ in × 12 ¹⁄₂ in (39 cm × 32 cm). Buy ¹⁄₂ yard (0.46 m) of cotton fabric to be the inside of your lunch bag. Spread the fabric flat and cut 2 rectangular pieces that are 15 ¹⁄₂ by 12 ¹⁄₂ inches (39 cm × 32 cm)
16. Cut a 1 in (2.5 cm) piece of Velcro and sew it near the top of the liner pieces. Lay the liner pieces flat and make a mark in the center of each 2 inches (5.1 cm) from the top. Peel apart a 1 inch (2.5 cm) piece of sticky back Velcro and stick the hook side on 1 of your marks. Place the loop side on the other mark. Then, use small stitches to sew the Velcro in place with your sewing machine
17. Stack, sew, and trim the inner liner pieces just like you did for the bag. Repeat the assembly steps with the 2 inner liner pieces that you sewed Velcro to. Leave the top side open and leave a gap along 1 long side so you can flip the bag inside out once you’ve sewn all of the pieces together.
18. Turn the liner right side out and put it into the bag so the seams line up. Flip the liner you just sewed so the pattern faces out. Push it into the bag so the patterned sides touch. Use your fingers to push the corners of the liner into the corners of the bag so the seams all line up.
19. Sew around the top side of the bag to secure the liner. Make straight stitches across the top of the bag and leave a ¹⁄₂ inch (1.3 cm) seam allowance as you work. Sew straight across until you’ve sewn around the entire top edge of the bag.
20. Flip the project right side out and sew the gap in the liner closed. Reach into the liner and find the gap that you left. Pull the liner out while you flip the bag right side out so the pattern is visible on the outside. Then, sew straight stitches right on the edge of the gap in the lining to close it. Push the liner down and enjoy using your new lunch bag!

Phew, your DIY Activity is ready.