Should You Sand Between Coats of Semi-Gloss Paint?

While applying glossy paints, you’ll need to sand between coats of the paint for proper adhesion between coats. But, do you have to sand between coats of semi-gloss paint?

You need to sand between coats of semi-gloss paints. This is to allow proper adhesion between the coats of the semi-gloss paint.

When semi-gloss paint gets dry, the top layer of the paint forms a hard and moisture-resistant film that doesn’t accept paint.

If you want to put another coat of semi-gloss paint on an existing coat, you’ll have to sand the existing coat to remove the moisture-resistant film. That will help the second coat of semi-gloss paint to stick to the first coat.

How Long Should Semi-Gloss Paint Dry Before Sanding?

How Long Should Semi-Gloss Paint Dry Before Sanding?

You should let the semi-gloss paint dry completely before sanding. On average, you should wait at least 2 hours after applying the semi-gloss paint before sanding. This gives the semi-gloss coating enough time to dry and harden.

If you don’t leave enough dry time between coats of semi-gloss paint before sanding, you’ll ruin the paint. This is because the semi-gloss paint will not be hard enough to handle the grit of the sandpaper.

If you sand semi-gloss paint before it’s dry enough, the sandpaper will remove the semi-gloss coating. Asides from that, the sandpaper will quickly gunk up with semi-gloss film.

The time to wait before sanding semi-gloss paint or the dry time of the semi-gloss paint depends on the environmental conditions, the type, and thickness of the semi-gloss paint.

For instance, if the first coat of semi-gloss paint is thick, it will take longer to dry enough for sanding. Also, if you applied the semi-gloss paint in a moist environment, then the semi-gloss paint will take longer to dry enough for sanding.

Oil-based semi-gloss paints take longer to dry than water-based semi-gloss paint. The best way to find out how long to wait before sanding semi-gloss paint is to check the manufacturer’s instructions.

Should You Sand Between Coats of Semi-Gloss Paint?

Should You Sand Between Coats of Semi-Gloss Paint?

You should sand between coats of semi-gloss paint to allow proper adhesion between the coats of the paint. Without sanding, there will be weak adhesion between each coat of semi-gloss paint.

Sanding also helps to remove dust nibs and grain on the existing coat of semi-gloss paint so the finish can dry smoothly and without pimples or bumps.

To further understand why you should sand between coats of semi-gloss paint, you need to know the features of semi-gloss paint. For semi-gloss paint to stick and adhere to a surface, the surface has to be textured and this is where the problem lies.

Why Should You Sand Between Semi-Gloss Coats?

When semi-gloss paint dries, the paint does not become textured. Instead, the paint dries to form a thick and moisture-resistant film. This thick film doesn’t accept or absorb any type of paint. Also, this film is usually glossy and slick which is the opposite of what the semi-gloss paint needs to stick. This creates a problem in terms of paint adhesion.

The problem is semi-gloss paint needs a textured surface to stick well but a coat of semi-gloss paint when dry forms a glossy and slick surface. So, if you want to put another coat of semi-gloss paint over existing paint, you’ll encounter poor adhesion.

That’s because the existing coat doesn’t have the textured requirements for the second coat of semi-gloss paint to stick. The solution to this problem is to sand the existing coat of semi-gloss paint.

When you sand, the sandpaper will remove the glossy layer on the semi-gloss paint. With the glossy layer out of the way, the existing semi-gloss coat becomes textured which means that a new coat of semi-gloss paint will now stick properly.

Do You Have To Sand The Last Coat Of Semi-Gloss Paint?

You don’t have to sand the final coat of semi-gloss paint because the final coat is meant to reveal the glossy sheen of the semi-gloss paint. You should only sand the final coat of semi-gloss paint if you want to apply another top coat or sealant over the final coat.

Also, the final coat of semi-gloss paint is the protective layer of the finish. In this case, the glossy and moisture-resistant top layer is not a problem since you wouldn’t be applying another coat on the final coat of semi-gloss paint.

The final coat here will be beneficial because it will protect the entire finish from moisture, dents, scratches, and early chipping. Sanding the final coat is only necessary if you want to apply a top coat of sealant over it. Asides from that, you shouldn’t sand the final coat.

If you sand the final coat of semi-gloss paint without putting a sealant over it, the finish will not last long as it will be easily affected by scratch marks, dust nibs, and moisture.

Do You Need To Sand Before Applying Semi-Gloss Paint?

It’s generally advised to sand before applying semi-gloss paint. This is to allow the semi-gloss paint to stick and adhere well to the surface. Also, sanding helps to get rid of dust and debris on the surface so they don’t cause pimples and bubbles in the semi-gloss paint.

If there is a sealant or an oil-based paint on the surface, you’ll also need to sand to remove the glossy top coat of the sealant or oil-based paint to allow the semi-gloss paint to stick properly.

Here are the top reason why you need to sand before applying semi-gloss paint:

  • For proper adhesion of the semi-gloss paint to the surface
  • To make the semi-gloss paint dry properly
  • To make the semi-gloss paint dry smoothly
  • To prevent the semi-gloss paint from turning sticky or gummy
  • To remove dirt and debris from the surface
  • To remove the top glossy layer of existing paint
  • To make the semi-gloss paint more durable

Sanding is important before applying semi-gloss paint but can you apply semi-gloss paint without sanding? Let’s find out.

Can You Apply Semi-Gloss Paint Without Sanding?

Can You Apply Semi-Gloss Paint Without Sanding?

It’s generally not advised to apply semi-gloss paint without sanding. This is because sanding helps to make the semi-gloss paint stick and adhere well to the surface.

However, there are a few cases where you can apply semi-gloss paint without sanding first. In the following scenarios, you can apply semi-gloss paint without sanding.

1. If The Surface Is Perfect

If the surface to be painted is clean, dry, and smooth, you don’t need to sand it before applying semi-gloss paint because semi-gloss paint will stick properly.

2. If There Is an Existing Flat Paint On The Surface

Semi-gloss paints stick well to flat paints because flat paints are water-based and have no natural sheen. In this case, all you need to do is to wipe and clean the flat paint to get rid of stains and dust on it. When the flat paint is clean, you can apply semi-gloss paint over it without sanding.

3. If You Need A Quick Fix or Touch Up

If you just need a quick fix over a spot or you want to touch up a small area on the surface, you can apply the semi-gloss paint without sanding.

What Happens If You Apply Semi-Gloss Paint Without Sanding?

If you apply semi-gloss paint without sanding the surface first, the semi-gloss paint will not stick or adhere to the surface properly. You should only apply semi-gloss paint without sanding if the surface is smooth, clean, and dry or if there is existing flat paint on the surface.

Asides from these scenarios, applying semi-gloss paint over a surface without sanding will lead to poor adhesion. You should know that poor adhesion is just the beginning of the problem. If you don’t sand before applying semi-gloss paint:

  • The paint will not stick well to the surface
  • The semi-gloss paint will turn sticky
  • The semi-gloss paint will come off with little force
  • The semi-gloss paint will smell
  • The semi-gloss paint will not be durable

You should know that in some cases, you’ll also need to sand and then prime the surface with primer paint before applying semi-gloss paint. So, what type of sandpaper should you use to sand semi-gloss paint? Let’s take a closer look at that.

What Grit of Sandpaper Should You Use To Sand Semi-Gloss Paint?

You should sand semi-gloss paint with fine-grit sandpaper. The right sandpaper for semi-gloss paint starts from 220-grit upwards. If you want to sand the surface before applying the semi-gloss paint, you should start sanding with medium-grit sandpaper. Then finish off with fine-grit sandpaper.

The medium-grit sandpaper will help to remove imperfections, pimples, bumps, and ridges on the surface. Medium-grit sandpaper also helps to remove pencil marks, glue, and nail holes in the wood that may have come from the carpenter’s workshop.

After sanding with the medium-grit sandpaper, the fine-grit sandpaper can be used to even the wood grain and smoothen the surface. This makes the semi-gloss paint dry smoothly.

Final Words

Overall, you need to sand between coats of semi-gloss paint. This is the only way to ensure proper adhesion between the coats of semi-gloss paint.

You should also prime the surface before applying the semi-gloss paint. Ensure to only sand semi-gloss paint with fine-grit sandpaper from 220-grit upwards.

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