A wool water bottle insulator is easy to make with scraps of wool, a snap, a needle and thread.
Wool is an excellent insulator and will help keep water cooler when ambient temperatures are warmer. Many countries supplied their troops with wool insulators for their canteens. It is still possible to find canteens and their wool insulators in military surplus stores.
This tutorial will show how to hand sew a wool water bottle insulator that can be custom fit for any size water bottle.
Step 1: Layout
There are three components to the wool water bottle insulator, hereafter referred to as "the insulator": the body, the bottom and the collar. The body is a tube which covers all of the water bottle with the exception of the water bottle neck and cap. The bottom fastens to the bottom of the body. The collar is attached to the top of the body and fastens around the neck of the water bottle thus securing the insulator to the water bottle. The collar closes with a snap.
Lay the water bottle down on a piece of graph paper and mark the length of the bottle from the rim to the bottom, as seen in Photo 1, then add .5 inches (13 mm) for the seam and mark on the paper.
Roll the bottle and fabric together and, with a pin, note where fabric meets fabric. Unroll the fabric onto the graph paper and add 1 inch (25 mm) for seam allowance and mark the paper as seen in Photo 2.
Complete the pattern using a ruler to draw a rectangle on the paper based on the two marks made earlier and cut it out (Photos 3 & 4).
Use a ruler to measure the length of the bottle neck (Photo 5). As the collar is made from a double layer of fabric, double this measurement and add 1 inch (25 mm) to this length for seam allowance and mark this length on a piece of graph paper.
Wrap a tape measure around the neck of the bottle and overlap the end by an inch (25 mm). Add an inch (25 mm) to this measurement for seam allowance and mark this length on the graph paper as well. Use the ruler to draw a rectangle on the graph paper.
Place the bottom of the bottle on the graph paper and trace the outline onto the paper. Trace the outline several times as the angle of the pencil varies as you trace the bottom of the bottle so that the outlines varies. Use your eye and the pencil to average the lines and darken in a final pattern. Add .5 (13 mm) inch to this outline for seam allowance and make a second, larger concentric circle which will be the cut line for the pattern. Photo 6 shows the patterns for the collar and the bottom.
Lay the patterns on the fabric (Photo 7) and cut out the fabric. Cut a little outside of the edge of the pattern as that gives a bit more fabric to work if needed. You can always trim the fabric if there is excess. The cut pieces are seen in Photo 8. Use an iron to press out any creases and prepare to sew everything together!
Step 2: Sewing the Body
As seen in Photo 1, wrap the wool fabric cut out for the body around the water bottle. Ensure that the fabric fits snugly around the water bottle. Overlap the edges and pin together.
Slide the fabric off and turn the edge of the fabric under to hide the raw edge of the fabric and to protect it from fraying (Photo 2). Readjust the pins as you tuck the fabric edge under.
Starting at the bottom, hand sew a back stitch approximately 1/8 inch (4 mm) from the edge.
Once you reach the top, tie a knot on the inside of the fabric.
Return to the bottom and sew a second seam, again using the back stitch, about .5 inch (13 mm) to the right of the first seam.
Photo 2 shows the two finished seams.
Step 3: Sewing the Bottom
Turn the fabric tube inside out and insert the water bottle. Pin the bottom to the fabric tube as seen in Photo 1.
As seen in Photo 2, hand sew a back stitch about .25 inches (6 mm) from the edge all the way around, being careful to constantly align the edges of the fabric tub and bottom. When finished, make a knot, remove the water bottle and invert the wool bag.
Photo 3 shows the finished bottom.
Step 4: Sewing the Collar
Cut the four corners slightly on the collar fabric rectangle. This will allow all four edges to be turned under to hide the raw edge and protect from fraying, as seen in Photo 1.
Starting with the shorter edge, use a separate needle and thread to sew a running stitch to keep the edge temporarily folded down as seen in Photo 2.
Fold the rectangle lengthwise and tuck all edges under and pin. Use the back stitch to sew the short edge first then move to the bottom long edge. As seen in Photo 3, insert a small folded piece of duct tape to add strength to the ends of the collar where the snaps will be attached.
Once you are almost to the halfway point on the bottom long edge set the collar aside and return to the fabric bag and insert the water bottle inside.
Fold the upper portion of the bag even with the rim of the water bottle as seen in Photo 4.
Pin the collar to the bag right where the vertical seam is located as seen in Photo 5.
Now continue sewing the bottom of the collar and simultaneously sew into the bag over the vertical bag seam. Only sew to the bag for about 1 inch (25.4 mm) and then continue sewing the bottom edge of the collar.
Continue sewing the other short side remembering to insert the small piece of duct tape.
Finally sew a stitch along the top edge, even though is is the folded edge. Once you come to the vertical seam on the bag, sew into the bag just like you did on the bottom edge.
To reinforce the area where the collar attaches to the bag, we will sew a few reinforcing stitches. As you are sewing the top edge and arrive at the vertical seam at the point marked 1 on Photo 6, change direction and sew a diagonal stitch from 1 to 2. Then sew a vertical stitch from 2 to 3. Sew a diagonal stitch from 3 to 4. Then sew a vertical stitch from 4 to 1. Now that you are back at point 1, continue sewing the horizontal stitch along the top edge, sewing from 1 to 3.
Once you arrive at 3, do not continue sewing the collar onto the bag but simply continue to sew the top edge of the collar only until you reach the edge where you initially started.
Once the collar is finished, determine the finished height of the bag by folding the wool fabric at the correct height and then tuck the raw edge under to create a double fold and pin (Photo 7). Use the back stitch to sew through the double fold to hem the upper portion of the bag.
As seen in Photo 8, the collar is attached to the bag in the center leaving the arms of the collar free to wrap around the bag opening to secure the bag to the neck of the water bottle.
Step 5: Attaching the Snap to the Collar
Place the water bottle in the bag and wrap the collar around the neck and determine where to place the snap.
Attach the snap as seen in Photo 1. A strip of velcro could be used instead of a snap. Simply sew the velcro in place.
The collar is designed to cinch the open insulator closed around the neck of the water bottle.
Step 6: Final Thoughts
The wool water bottle insulator is a simple project that anyone can make. I used salvaged wool from a garment destined for the landfill. The wool insulator is a predecessor to today's "can cooler" and is a time-tested way to keep water cool on a hot summer day. The wool can be moistened with water to increase the cooling effect. The wool insulator can also keep warm beverages warm, but a vacuum flask (thermos) is better suited for keeping hot beverages hot.
The wool water bottle insulator could be made with a sewing machine in a fraction of the time it took to hand sew this project but I find hand sewing to be enjoyable and relaxing, so decided to break out the needle and thread.