Instant Nails make a great patch. Works great for natural nails or Instant Nails. Cut a piece wide enough to cover the crack or weak area, plus a bit more to allow for tapering and adhesion to the sides. You can cut it longer and use the excess length as a handle. Then just glue the Instant Nail patch to your nail bed. Don't worry about how neat it looks at this point, just get it to stay on, as you're going to be filing, tapering and smoothing the patch into your natural nail. Make sure the shape matches the contour of the area you're repairing. Once the patch is glued to your nail, add more glue all around the edges. Let dry, or spray some mild nail glue dryer. Then file and taper the patch into your nail bed. Electric rotary nail files are really a necessity for this because of their accuracy, especially at tapering around the edges. Use a fine grit file and/or 1500 grit sandpaper to finish. Makes a really strong repair. You can also use this technique if you lose the "corner" of a thumbnail, or if you need a partial nail.

                                                     Click here to see how to apply a patch

Maintenance:  Maintaining Instant Nails is different than maintaining natural nails. Here's a few simple things you can do to help you maintain your Instant Nails.

You should always have some 1500 grit sandpaper with you to file the tip and surrounding areas of the nail if it should get roughed up. In case an Instant Nail should start to lift up a bit, you should always have some super glue around to instantly glue it down. Sometimes it's better to file off or "thin" the part of the nail that's lifting, then add a bit of super glue to the area. A rotary nail file is very much recommended for maintaining any type of artificial nail or wraps. If you get a weak area or a crack , the precision of a rotary nail file makes quick work of repairing, patching, and tapering the nail. Usually any maintenance that is needed will take only a minute or two with the proper knowledge and tools.

Super Glue Tips: When replacing the cap on the super glue, you don't need to put it on too tight, just loosely apply it and store upright in a cool dark place. (This, of course, applies only if you are not traveling with it). To test if your super glue is old, simply dispense a drop from some height, and watch it to see if it's at all "stringy". If so, it's old. Get some new glue. ( This test is for thin glues). If you're going to be using any nail glue dryer (accelerator), make sure that the original bottle of super glue is capped, and put away, far from where you're using the nail glue dryer.

        Super glue is not bad for your nails if used correctly. It's what "Fingernail Glue" is. It's been used for this purpose for many years. It's not perfect, but currently it's the best glue for fingernails. Super glue is non toxic. As a matter of fact, they used to use it for medical stitches in the exact same form that you can buy right off the shelf. It actually has antibiotic properties. Nowadays they use a slightly different form of  cyanoacrylate for medical stitches.      
        Heat and moisture will decrease the shelf life of super glues. Unopened bottles can be stored in a freezer or refrigerator, but allow them to reach room temperature before using. Don't refrigerate open bottles. Keep your open bottles in a cool place that won’t be exposed to direct sunlight and store away from bottles of accelerators.

Electric Rotary Nail files: Electric rotary fingernail files if operated properly are very easy and safe to use. They're great for any type of artificial nails, nail wraps, or repairs. Guitarists who use any type of artificial  nails should consider owning one. Use very little pressure, let the bit do the work. Always use a very light touch, especially if you're not familiar with the bit and drill that you're using.

When filing under the nail, avoid causing pressure on the surrounding skin. Use a light touch when working under the nail. Just remember too much pressure can build up heat, so go slow and let the bit do the work. If you have a variable speed drill, use a slower rpm for under the nail.

Don't let the bit stay in one place or in contact with the nail all of the time. Move the bit around and lift it off the nail to cool if needed. When working with artificial nails, always file from the middle out. Don't start at the corners, as that can cause the artificial nail to to lift and pull off. When tapering the corners of artificial nails, start from the middle and work outward.

Once you get used to rotary files, you'll wonder how you ever got along without them. They do a very quick, precise job, and are a great asset to guitarists who use any type of artificial nails or wraps.

Emory board Files:  If you're using an emery board type file that has a sharp edge along the side, you can take another rough grit file and file down the sharp edge of the file you'll be using on your nails. Sometimes when filing a fingernail, the underside of the file can inadvertently cut into the pad of your finger underneath the nail. This can be pretty painful and keep you from playing for a day or two. Just a tip on how to avoid this.