Superglue is most suitable for what kinds of surfaces?

Superglue is most suitable for non-porous surfaces due to its chemical properties and bonding capabilities. Non-porous surfaces, such as glass, metal, and plastic, have smooth finishes that allow the cyanoacrylate in superglue to form strong, durable bonds. These surfaces do not absorb the adhesive, enabling it to cure effectively and create a robust connection.

When considering porous surfaces, superglue may be less effective because the adhesive can penetrate into the material, reducing its bonding strength and effectiveness. Rough surfaces introduce challenges as well, as the irregularities can hinder the adhesive's ability to contact sufficient surface area for a strong bond. Variable surfaces can further complicate the bonding process due to inconsistencies in texture and absorption, which may not provide a reliable foundation for the superglue to perform effectively.

Hence, non-porous surfaces align perfectly with the intended use of superglue, making it the most suitable choice among the options provided.