Sandpaper is an abrasive industrial paper coated with grit, used to smooth, roughen, or prepare surfaces for finishing treatments such as paint, varnish, or gilding. In framing and woodworking, sandpaper plays an essential role in refining surfaces of wood, metal, or gesso before coatings are applied, ensuring both adhesion and a professional finish.

Characteristics

Abrasive Surface: Coated with materials such as aluminum oxide, garnet, silicon carbide, or emery.
Varied Grit Sizes: Ranges from coarse grits (40-80) for heavy material removal to fine grits (400+) for polishing.
Flexible Backing: Typically uses paper or cloth backing, with some designed for wet/dry use.
Disposable Tool: Designed to be replaced once the abrasive particles wear down.

Applications in Framing

Surface Preparation: Smooths wooden mouldings before applying stain, paint, or gilding.
Gesso Work: Levels gesso-coated frames for a polished, uniform surface prior to finishing.
Metal Frames: Can be used lightly to remove oxidation or prepare metal for refinishing.
Restoration: Helps repair or refinish old frames by removing previous coatings.

Advantages

Creates smooth, even surfaces for better adhesion of finishes.
Available in a wide range of grits and materials for different applications.
Cost-effective and easy to use in both professional and DIY framing projects.
Essential for preparing raw materials for conservation or decorative treatments.

Limitations

Over-sanding can damage delicate surfaces or remove too much material.
Produces fine dust that requires proper ventilation and protective equipment.
Not reusable once grit becomes dull or clogged.

Best Practices

Choose the correct grit size for the task-start coarse and move to finer grits for a smooth finish.
Sand with the grain of wood to avoid visible scratches.
Use dust masks and adequate ventilation when sanding.
For conservation-sensitive work, avoid aggressive sanding that could compromise original materials.

Sandpaper