How to mend a cracked nail
If you have cracked a nail, my sympathies. It is a huge frustration and can severely hamper your playing. If the nail is still attached you can usually salvage it with the following technique.
1. Get some nail glue and a tissue. Usually a tissue will have several layers so separate them until you have a single sheet of tissue paper.
2. Place a small amount of glue over the crack and let it dry
3. Place the tissue over the crack and wet the area with nail glue letting it dry. Don’t go overboard with the glue as nail glue and super glue deteriorate the nail over time so use it sparingly.
4. Repeat #3 so that there are three layers of glued tissue paper over the crack. Let the glue dry completely each time.
Take care! Nail glue and super glue will bond with skin very, very quickly. If this happens soak the skin in warm soapy water or better yet, use nail polish remover to dissolve the glue. Do not try to pull the skin apart, you will get hurt!
This process forms a very durable shell around the cracked nail and if you are careful with the nail it can last until the crack grows out. If need to take off the glue and tissue paper use nail polish remover. Put the nail polish remover on a cotton pad and place it over the glued area. The remover will dissolve the glue and with a little patience and gentle rubbing the area will be clean enough to start over.
Nails that wear down
A very simple but effective trick to stop nails wearing down from practicing is to put tape on them. You may have to experiment with different tape varieties as some work better than others depending on their glue and elasticity. I personally use brown packing tape.
Cut a small rectangle of tape and place the sticky side up underneath your nail. Then, fold it over the top of the nail and press it down. The tape may crease on the top of the nail but as long as it has a smooth surface along the playing edge of the nail you will be fine. You should still be able to get a good tone from your nails and they will last a lot longer!