Choosing the Right Grit for Sanding Drywall Joint Compound

When it comes to sanding drywall joint compound, the choice of grit can greatly impact the final finish. For a smooth and professional-looking result, selecting the appropriate grit is crucial. In this article, we will discuss the differences between P100 and P220 grit and provide a detailed guide to the sanding process.

The Importance of Grit in Sanding Joint Compound

When fixing drywall, the joint compound needs to be sanded to achieve a smooth and professional finish. The choice of grit, whether P100, P120, P150, or P220, can significantly affect the final texture of the wall. A coarser grit, such as P100 or P120, is typically used for the initial sanding layers to remove excess joint compound and smooth out the joints. The final sanding, however, requires a finer grit to achieve a smooth finish without scratching the surface.

Sanding Process Breakdown

Initial Sanding

For the first few layers of joint compound, using a coarser grit sandpaper such as P120 or P150 is recommended. This grit helps remove excess material and smooth out the joints. It's important to use a sanding block or a pole sander to maintain an even surface during this process. Always wear a dust mask to avoid inhaling dust particles.

Final Sanding

For the final sanding of the joint compound, a finer grit, such as P220, is appropriate. This grit helps achieve a smooth finish without scratching the surface. The P220 grit minimizes the risk of visible scratches when you paint the wall. Light and even pressure is key during this process to avoid over-sanding and damaging the drywall.

User Experience and Preference

While many professionals recommend using P220 for the final sanding, some users prefer coarser grits like P100 or P120. The amount of work required to remove excess joint compound can vary greatly based on the skill level of the finisher. Some finishers may be able to achieve a smooth finish with less sanding, while others may need to scrape and apply additional layers of joint compound.

One experienced finisher notes that using P220 is fine for the final layer, but some users find that a 100-grit or even 150-grit works well enough. The key is to balance the need for smoothness with the risk of clogging the sandpaper with drywall dust. Using a sanding screen or finer grit paper can clog quickly and become ineffective for further sanding.

Painting and Finishing

It's important to remember that even after sanding, the drywall will be primed and painted. The paint will swell and fill any small sanding marks, creating a smooth finish. This means that a slightly coarser grit may suffice, as the imperfections will be hidden by the paint.

User experience also indicates that using P100 or P120 can be sufficient, especially if the finisher is meticulous about their work. For an even smoother finish, lingering marks can be addressed with a damp sponge and water prior to applying PVA (Water-Based Paste Wood Filler) or another finishing product.

Overall, the choice of grit for sanding drywall joint compound depends on personal preference, skill level, and the specific needs of the job. Whether you opt for P100, P120, P150, or P220, the goal is to achieve a smooth, professional finish that will last.