Your electric guitar's finish can experience any number of problems as you play it over the years. Many of these problems have to do with the use and abuse of the instrument as well as the weather conditions that it is subjected to. I will explain a few different guitar finish problems in this article.
Warning: Before we go on to learn about finish repairs, I urge you to think twice before experimenting with your guitar's finish. Finish can be a tricky thing. In most cases, if you are not experienced, you will probably make the finish problem either worse or more noticeable. Also, if you have a vintage guitar, I would suggest that you not tamper with the finish at all. A vintage guitar's value will decrease drastically once it has been refinished.
Lacquer cracks are generally caused by drastic changes in temperature or humidity. The lacquer is attached to the outside of the wood. While the wood can expand and contract with differing amounts of humidity in the air, the lacquer, for all practical purposes, cannot. This is the major reason behind lacquer cracks--the wood moves while the lacquer remains still. Most lacquer cracks start out small and internal, often called crazing. These cracks look like hairline cracks, but cannot be felt when you run your finger across the top of the finish. The reason why the cracks feel smooth on the outside of the guitar is because the lacquer is cracking from the inside out. It's cracking where it joins the wood. Some of these cracks will never materialize into an external crack, where as, others will. It just depends on how well you take care of your guitar.
Many vintage instruments have this sort of cracking, due to their age. If your vintage guitar has finish problems, think twice before you have it refinished. Refinishing a vintage guitar will decrease its value.
Please read my maintenance article on how to prevent these types of cracks from happening to your guitar.
It is impossible to prevent your guitar from getting scratched up, so why even try. I'm just kidding. Although there is no real way to prevent getting scratches on your guitar, there are some ways of removing them. Shallow scratches can be removed or buffed out of the finish in your guitar if you know how to do it. Deep scratches on the other hand, cannot be removed and will cause a bigger problem if you they to buff them out.
Shallow scratches can be wet sanded, buffed, and polished again. These scratches look like small hairline scratches on the finish of your guitar. You can wet down a piece of 1000 grit sand paper with water and soap suds and lightly sand down the area with the scratch. Keep in mind, you only want to sand down a little of the topcoat of lacquer--nothing more. Then take a buffing wheel or rag and work in some buffing compound. After the area has been buffed, you can polish it to a high shine. After you have it polished, you should not be able to see any hairline scratches.
Deep scratches are scratches that you can feel with your fingertips or fingernail. These kinds of scratches are near impossible to sand out. They are too deep in the finish. If you go after a deep scratch with sand paper, you will probably sand through the topcoat and into the color coats or raw wood. In this case, the guitar may need to be refinished to hide your sand through. Deep scratches are better left alone or brought to a professional. Do not try to fill these scratches with extra lacquer or other filler. Trust me. It will probably look worse than if you would have just left it alone.
This is not a very common event, but it does happen. Since the lacquer is sprayed on top of a clear coat or sealer coat, the lacquer is not actually attached to the wood of the guitar--the sealer coat is. This finish problem is most likely caused by an improper finish. The topcoat is not properly sticking to the sealer coat. To fix this problem, you will need to strip the finish off the guitar and refinish it again. If you just spray more lacquer on top of the de-laminated finish, you will end up having the same problem later on.