Yes, it is possible to apply sealant without a sealant gun, although using a gun often ensures a more precise and controlled application. For smaller projects or touch-ups, applying sealant directly from the tube can be effective, especially if the sealant has a nozzle designed for direct application. However, for larger projects or when a more even application is required, using a sealant gun is recommended. A sealant gun helps to apply the sealant evenly and smoothly, reducing the risk of air bubbles and ensuring a professional finish.