Although minor scratches to your car bodywork may be unsightly, they are unlikely to warrant a trip to the garage as it will be easier to repair them yourself with the use of car touch up paint. Understanding the qualities of both paint pens and aerosols will help you to determine which one will be the best for your purposes.
The preparation required to enable you to apply the car touch up paint is much the same whether you intend to use paint in the form of an aerosol or a pen. The surface will need to be cleaned before primer needs to be applied to prepare the surface. Both varieties of paint will require some preparation directly as well. While it is recommended that both are shaken thoroughly to mix the paint if it has settled, an aerosol will be able to be used immediately. A car touch up paint pen will need to have the nib worked on until the paint begins to flow.
It will be easier to apply the paint in a precise manner when you use a car touch up paint pen. It will take a little more work to hone your technique when making use of aerosols of car paint due to the distance that you will need to hold the can away from the surface. It will be easier to keep your hand steady when a pen nib is pressed to the surface.
The type of car paint touch up method that you choose will depend on the size of the area that you need to work on. A paint pen will be the best option for small scratches and defects as it is easy to apply the paint directly where it is required. When larger sections of the car require the application of paint, it will be easier to use an aerosol.
The amount of protection required by both the car and the person using the paint differ due to the methods of application. An aerosol spray will result in fine particles floating in the air which will require use of a face mask to prevent from inhaling them. It will also be beneficial to wear other protective items, such as overalls and gloves for easy clean up. A paint pen will not require you to wear this level of protection as the liquid is easier to apply directly. Maybe a facemask will be required to prevent the risk of inhaling any paint fumes.
When using car touch up paint in the form of a aerosol, it will be necessary to cover the sections of the car that do not require paint. This is due to the fact that the scope of the spray can be wide enough to incorporate sections where it is not required. This will not be such an issue when using a paint pen.
When painting a car, it is important to avoid any action that will lead to drips or a concentration of too much paint. This tends to be easier with a paint pen due to the close proximity to the surface you are working on. Leaving the spray in the same place for too long can result in drips.