You can buy bags that have buckwheat hulls in them at the kiosks at the mall, and I understand bags like this that contain cherry pits can also be found (and apparently smell wonderful when hot) and I am sure there are many other iterations I have never heard of. However, rice works very well, is readily available and inexpensive. A simple bag can be made in an hour or less with a minimum of fabric and a couple of cups of rice. You can make a cute pieced version with small scraps or a simpler iteration using a single fabric. I will cover how to make a little scrappy heart and a couple small hand warmers out of a single fabric.
You will need for the heart:
two 2x3" pieces of fabric to make your heart
about a 5x7" piece of background plus a few scraps to finish it out to the final size
a 5x5" piece for the back
two 5x5 pieces of ALL COTTON batting (synthetic will melt)
You will need for the solid fabric hand warmers:
Two 4x8" pieces of fabric (cute novelty prints and seasonal prints are fun)
Two 4x8" pieces of ALL COTTON batting
Note that you can make these without the batting, as I did for years. However the batting helps to insulate the heat from the rice, making it more difficult to burn yourself with an accidentally overheated bag and it also causes the bag to hold the heat a bit longer.
The heart in this project will be, as we say, "wonky" and unplanned. First take the two 2x3" pieces and lop off both top corners of each as well as a long slanted cut off the bottom left corner on one and the bottom right corner on the other. If they seem to need further amendment to sort of look like a heart take off a vertical sliver on the outside of the offending piece on the same side that the long slanted cut came from. Then take the background fabric and begin cutting generous triangles off to fill in the spaces around the heart shape.
Begin sewing the triangles to the heart fabric in this order; inside upper heart corners, outside upper heart corners, vertical cuts, long slanting cuts. Now, don't do this half heartedly.... hahahaha! I kill myself! Really, you should end up with two half hearts. Trim the inner edges straight and lay them rights sides together and sew the middle seam. I often press this one open to avoid bulk. What a nice crumby heart you have! Now trim the outside edges straight and take your scraps and begin adding them in order to make a piece about 6" square.
Once you have a large enough piece you can trim the best 5" out of the middle. This allows you to do a final placement of the heart for the best possible effect.
|ready for trimming
Now the rest of the instructions apply to any fabric you want to use. Layer each fabric piece with the corresponding batting piece. At this point you may decide to add some detail with quilting. Pieces this size don't need to be quilted, but I find that these little projects give me a chance to practice rusty free motion skills so I quilt mine. So, quilt as desired, or not.
|layered and quilted
|note the unsewn sections on the bottom edges
Place the 5x5" front piece and back piece together, sew a 1/4 - 5/8" seam all the way around EXCEPT for about 2" in the middle of one side. Be sure to back-stitch at the free ends. This opening will allow you to turn it right side out. Use the eraser end of a pencil to poke out the corners.
Now comes the rice. A bag this size will take a little more than a half a cup of rice. Experiment a little for yourself... You want it pleasantly full, but not so full that it is hard to hand stitch closed. Pin the opening closed (so you don't spill rice all over the floor) and slip or whip stitch the opening closed.
|whip stitch the opening
Leave a long tail after you knot off the end and take a long stitch through the body of the bag. Cut the thread off at the surface. The long tails, just like in quilting, prevent the knot from working its way loose. now you have a cute little "warm heart" to give to a teacher or friend to keep her hands toasty on cold days working the carpool line or walking to the bus.
|bury your end after the knot, just like with quilting
A word about warming these in the microwave. Please use caution and common sense. It is possible to heat them to the point that they will burn you (they also tend to take on a scorched smell if over heated). For bags containing more rice, more time is necessary to achieve the desired temperature. Hand warmer sized bags take no more than about 1 minute if you do them together. Larger bags with 3-4 cups can take 2 to 2:30 minutes. If I am giving them as a gift I always include a set of written instructions. I experiment with the finished bag to find the time that works best for my comfort and always give a shorter amount of time in the instructions.
That being said, they make great gifts for teachers and bus drivers, they are a great comfort to sick children with the chills or a tummy ache, they are awesome on sore muscles and stiff necks. My large channeled version (seen below on the left) is used in the winter nightly to warm up my otherwise frozen feet. The train bag and the skull bag belong to my boys and the patchwork bag was made by one of them and was the first one we tried batting in. I have also used the hand warmer size bags (minus the cotton batting) as mini cold packs by storing them in the freezer. They do not hold cold as long as they hold heat, but they are a small comfort to minor bumps on a head or shins when frozen peas are a little overkill. My sister heats up half a dozen medium sized bags and puts them in a cooler to take to late fall soccer games to keep the 'benchwarmers' and fans warm on the sometimes frigid fall mornings. After a while of hard use they get sort of grungy looking and the rice begins to smell, well, used. At that point, if you like the bag enough you can open it up at the hand sewn seam, dump the rice, wash the shell and fill it with new rice.
|my family's stash of rice bags, minus the ones kept in the freezer
I hope you enjoy this project. Forgive me if it was not clear (and make a comment and I will try to make it understandable) as it is my first written tutorial attempt.