Polyurethane (PU) is a common type of finish used on guitars. It is durable and provides a high gloss finish.
However, it can be difficult to repair if it becomes damaged. By following these directions, you can easily repair Polyurethane guitar finishes.
What is polyurethane

Polyurethane is a polymer that is made up of repeating units of urethane. It can be made in various forms, including foam, elastomer, and resin.
Polyurethane is used in a variety of applications, including furniture, bedding, automotive seats, insulation, and musical instruments.
How to repair a polyurethane guitar finish
- Clean the area to be repaired with a damp cloth. This will remove any dirt or debris that could prevent the repair from bonding properly.
- Apply a thin layer of epoxy to the area to be repaired.
- Lay a piece of plastic wrap over the epoxy and smooth it out with your fingers. This will help create a smooth surface for the repair.
- Allow the epoxy to cure for at least 24 hours before proceeding to the next step.
- Once the epoxy has cured, sand the area around the repair with a fine-grit sandpaper. This will help blend the repair into the surrounding Polyurethane finish.
- Apply a thin layer of Polyurethane finish over the entire repair area.
- Allow the Polyurethane to dry completely before buffing it out with a soft cloth.
What to do if your polyurethane guitar finish is damaged – Polyurethane guitar finish repair

If your polyurethane guitar finish is damaged, you can try to sand it down and refinish it, or you can replace the finish altogether. If you have a lacquer finish, you may be able to buff out the damage and restore the shine.
How to prevent damage to your polyurethane guitar finish
To begin with, it is important to understand that polyurethane is a plastic. Therefore, it is vulnerable to scratches, dents, and other types of damage. In order to prevent your polyurethane guitar finish from being damaged, you need to take some precautions.
Firstly, always store your guitar in a case when not in use. This will protect the finish from being scratched or chipped if it accidentally falls over.
Secondly, avoid exposing your guitar to direct sunlight for extended periods of time. UV rays can cause the polyurethane to yellow and become brittle.
Thirdly, be careful when cleaning your guitar. Do not use harsh chemicals or abrasive cleaners as these can damage the finish. Instead, use a soft cloth and a mild cleaner specifically designed for guitars.
Finally, avoid placing your guitar near sources of heat such as radiators or fireplaces. The heat can cause the polyurethane to warp and crack.
By following these simple tips, you can help to prolong the life of your polyurethane guitar finish and keep it looking like new for longer.
How to avoid scratches to a polyurethane finish
To avoid scratches to a polyurethane finish, it is important to avoid using harsh cleaning chemicals or abrasive pads when cleaning the surface. Instead, use a soft cloth or microfiber towel to dust the surface and a mild soap and water solution for deeper cleaning. When scrubbing the surface, be sure to use gentle circular motions.
Different types of polyurethane finish are available for guitars.
The most common type is the glossy finish, which is what you typically see on new guitars. This type of finish is very shiny and makes the guitar look new. There is also a semi-gloss finish, which is not as shiny as the glossy finish but still has a bit of shine to it. Lastly, there is a matte finish, which is completely flat and does not have any shine to it whatsoever.
The benefits of a polyurethane guitar finish
One benefit is that it is very durable and can withstand a lot of wear and tear. This is ideal for those who play their guitar frequently or for those who gig regularly. Another benefit is that it is very easy to keep clean and free from dirt and grime. Finally, it gives the guitar a nice shine and makes it look new and fresh.
In relation to the overall tone of the instrument, these types of finishes can also enhance the tone of the guitar by increasing the sustain and resonance of the strings.