I just learned that reusable cloth menstrual pads are classified as "medical devices", and that their manufacturers are required to pay a fee of several thousand dollars a year to register with the FDA. Mostly these are made by women who run small sewing businesses out of their homes; few can afford to pay the fee and remain in business.
But it is easy to make your own washable cloth menstrual pads. Cloth pads are softer, more comfortable, and very much cheaper than disposable pads. They also don't contain the chemicals that increase crampiness for some women. I used to have trouble finding a store that carried the right brand and size of super-mega-maxi-huge pad; now I have exactly what I need.
There are a lot of ways that you can sew your own. Here I am giving a simple yet customizable procedure for making cloth pads. These can be sewn by machine, or by hand.
1. Make template. Draw your preferred pad size and shape on a piece of paperboard or cardboard, and cut it out. If you prefer pads with wings, make one template for the padded part, and one for the pad as a whole (add seam allowances if you want a more finished look). Personally, I find that wings tend to facilitate wrap-around leaks, so I prefer pads without wings. Wearing them inside snug-fitting underwear is sufficient to keep them in place.
2. Gather fabric. Cotton flannel makes soft outer layers, and absorbent inner layers. Good sources of flannel for recycling are old flannel shirts, sheets, and receiving blankets. The inside layers of the pad can also be made of terry cloth from old towels and washcloths; a layer of terry is worth about two layers of flannel. Some women prefer other natural fibers such as bamboo or hemp. The fewer dyes that are in contact with your crotch, the better, especially if you are using newer fabrics. Brand-new fabrics should be washed and dried to pre-shrink them before cutting. The number of layers needed varies, from 2 layers of flannel for a panty liner, to 6 layers (or two layers of flannel and two of terry) for a thick pad.
If you want a waterproof layer, add a layer of PUL (polyurethane laminate fabric) just inside the outermost layer. I prefer not to, so that I can stack two pads for increased absorbency. PUL also shouldn't be dried in the dryer, as the heat will cause it to de-laminate rather quickly.
3. First cut. Cut the pieces for the layers. At this point, I recommend cutting them about 1/4 inch larger than the template on all sides, and trimming to size after the second sewing. That is easier than trying to keep several precisely cut shapes stacked precisely while sewing.
4. First sewing. This is the stitching that holds the layers together. Stack all the layers of the pad or the central pad if you are making wings, and use the template to mark the shape of the pad. (For marking, I usually just use a ballpoint pen.) Don't sew on this line yet; sew 1/4 inch inside it with straight stitch.
5. Second sewing. This stitching edges the pad. Since I sew with cantankerous old sewing machines, I recommend doing this before trimming the edges. Sew a line of zigzag stitch just inside the line from the template. Then trim the edges just outside this stitching.
6. Add wings and closure (optional). Center the pad on the "wrong" side of one of the outer winged pieces, and sew it in place. There is more than one way to do the rest of it. You can repeat Steps 4 and 5 for the outer winged layer, or you can sew it so that the raw edges are hidden (assuming you included seam allowances in Step 1): Put the other outside piece onto it, with right sides together, and sew most of the way around, but leave a gap large enough to turn the pad right-side-out through. Clip and notch into seam allowances at curves almost to stitching line, if needed to make it lie flat. Turn the pad right side out, then sew the gap closed. Optional: stitch around through all layers. Sew on snaps for a closure; velcro and snaps that are set with a snap setter tool are other options.
7. Use, storage, and laundering. To use, put one into snug-fitting underwear. Fasten wings, if any. Used pads can be soaked in water in a covered container (change water daily), or folded and stored dry. To launder, wash in cold water with detergent, and then in hot water with detergent. Dry in the dryer on Hot (unless PUL was used), or hang to dry. Lingering odors can be removed with a vinegar rinse.