Sanding sealer is often a shellac or lacquer formula applied over uneven wood before a top coat. But, can you put sanding sealer over wood stain?
You can apply sanding sealer over stain, but you can’t use sanding sealer as the final coat. You must apply a clear coat or top coat over the sanding sealer.
It’s recommended to sand the sanding sealer before applying a top coat. This removes blemishes and imperfections in the sanding sealer coat.
Does Sanding Sealer Stick To Stain?
Sanding sealer sticks to wood stains. That’s because the sealer coating has a formula that allows it to stick to every type of surface.
Since sanding sealers are designed to be used on poor surfaces, the sealer is formulated to adhere well regardless of surface type. Plus, wood stains don’t have any ingredients that will repel the sanding sealer.
However, sanding sealer might not stick well to oil-based stains. That’s because oil-based stains, when dry, form a glossy sheen that prevents anything from sticking, including sanding sealer. The texture of the glossy sheen is slick and difficult to stick to.
To put sanding sealer over an existing oil-based stain, you’ll have to remove the glossy layer first.
Apply Sanding Sealer Before or After Stain?
Sanding sealers are designed to be used before applying stains. The sealer helps the wood stain to stick better by removing imperfections from the wood.
The sanding sealer purpose is to help wood stain (or other paints) stick to rough, porous, and uneven wood. It seals porous woods and prevents wood from sucking stain excessively.
The sanding sealer should be used on bare wood (before applying stain). For instance, if the wood has patches or doesn’t stain evenly, apply two coats of sanding sealer, and the sealer will make the wood smoother and ready to accept stain.
However, you can apply sanding sealer after stain, but you must apply a top coat over the sanding sealer too. Sanding sealer shouldn’t be the final layer. You can apply sanding sealer between coats if you want to apply multiple coats of topical stains, such as gel stains.
For instance, if you want to apply a clear coat over the stain, you can apply one coat of sanding sealer to prep the stain for the clear coat. But, you must sand the sanding sealer medium-grit sandpaper (320-grit) before applying a top coat. Sanding helps the top coat stick better.
However, you shouldn’t use sanding sealer before applying penetrating stain, such as oil-based stain. That’s because the sanding sealer prevents the oil-based stain from penetrating wood. If the oil-based stain can’t penetrate the wood, it won’t stick and will peel off after a while. The oil-based stain should be applied over bare wood.
The best type of stain to use over sanding sealer is topical stain or non-penetrating stain.
How To Apply Sanding Sealer Over Stain?
Applying sanding sealer isn’t hard; this guide will show you how to do that in just 4 simple steps. However, there are certain rules and conditions you should remember before embarking on this task:
- Never use sanding sealer as the final coat.
- The stain should be dry enough for recoat before applying the sanding sealer.
- Don’t apply sanding sealer over oil-based stain unless you remove the glossy sheen first.
- Never use sanding sealer if you would be putting penetrating wood oil over it.
Now, let’s get to work. To apply sanding sealer over a stain, you’ll need the following tools and supplies:
- Fine-grit sandpaper
- Clean rags
- A pair of work gloves
- A petroleum-based solvent like mineral spirit (for oil-based stains)
1. Check If The Existing Stain Is Dry
The stain must be dry before you apply sanding sealer over it. If the stain isn’t dry, the sanding sealer won’t stick, and the finish will turn sticky. Also, the paint pigments on the stain will stain the sanding sealer.
To know if the stain is dry enough, swipe 320-grit sandpaper over the stain. If the sandpaper doesn’t move freely, the stain isn’t dry enough. If the stain is ready for a recoat, 320-grit sandpaper will glide freely.
If you don’t have sandpaper, wait at least 4 hours before applying a sanding sealer over the stain.
2. Sand The Existing Stain
If the stain is dry enough, sand it. To sand stain, use fine-grit sandpaper. The sanding will remove bumps and imperfections from the stain coating. It also created ridges in the stain coating that the sanding sealer can bite into to stick better. However, you shouldn’t sand too hard because you can remove the stain completely.
After sanding, remove the dust that is produced by sanding. To remove dust, use a clean rag.
3. Apply The Sanding Sealer
Once the stain is sanded and clean, apply the sanding sealer. To apply sanding sealer, use a paintbrush and apply thin coats. You must cover the surface evenly so the new stain can be absorbed evenly.
Apply one coat of sanding sealer if you don’t want to switch the color of the stain. Apply two coats of sanding sealer if you want to switch the stain color or sheen.
For instance, if you want to move from a dark topical stain to a light topical stain, you can apply two coats of sanding sealer on the dark stain to prevent the dark shade from affecting the light new stain.
4. Scuff The Sanding Sealer
Sanding sealer takes one hour to dry. Once the sealer is dry, scuff or sand it. Sanding removes blemishes and tiny imperfections from the sanding sealer. These imperfections can prevent the new stain from sticking well to the sanding sealer.
If you don’t sand sanding sealer, the imperfections will prevent the new stain from sticking well. And, these blemishes will show through if you use a clear coat.
To sand sanding sealer, use 200-grit sandpaper. You shouldn’t use coarse or medium-grit sandpaper as it can remove the sanding sealer.
After sanding, remove dust and apply the stain.
Stain Dry Time Before Sanding Sealer
Stain should dry for 4 hours before putting sanding sealer over it. After the stain dries, it will be hardened enough to support a sanding sealer coat. However, the time it takes stain to dry before applying the sanding sealer depends on the type of stain and drying conditions. But, 4 hours is more than enough for most stains.
If you apply sanding sealer before the stain dries, the stain won’t dry and will turn sticky. To dry, the solvent of the stain needs to evaporate, but if you apply a coat of sanding sealer, you will block the evaporation process. This leads to a sticky and blotchy stain.
However, you don’t have to apply a fresh wood stain just to put sanding sealer over it. If the wood is already stained, you can apply sanding sealer without having to apply a new coat of stain. This is because the old stain on the wood is strong enough to support the sanding sealer coat.
Can You Stain Over Sanding Sealer?
You can only apply topical stains over the sanding sealer. You shouldn’t apply penetrating wood stain over the sanding sealer as the stain won’t stick.
Regular wood stains are penetrating finishes and won’t stick to sanding sealer. Penetrating stains need to penetrate the wood pores to stick, but since the sanding sealer will seal wood pores, the stain won’t be able to penetrate the already-filled wood pores. Therefore, if you apply penetrating stains over a sanding sealer, the stain will smell foul, turn sticky, and won’t stick.
However, water-based stains and clear coats can stick over sanding sealer because water-based stains don’t need to penetrate wood as deeply. But, you must sand.
On the other hand, topical stains, such as gel stains, don’t need to penetrate the wood pores to stick. As such, topical stain can stick over sanding sealer.
Mixing Sanding Sealer With Stain
You shouldn’t mix sanding sealer with stain. That’s because stain and sealer have different formulas and ingredients that aren’t compatible.
Also, both products have different functions. Stains are designed to penetrate the wood and change the color of the wood grain. Sanding sealers are designed to prevent penetration, so mixing both products means that they will get in each other’s way.
To get the best of both worlds, apply a sealer over the wood stain. Sealers such as polyurethane, varnish, or lacquer can be applied over the wood stain and protect it from moisture.
You can use sanding sealer over stain, but you also must apply a top coat of sanding sealer. That’s because sanding sealers can’t be used as a final coat.
Penetrating and regular wood stains don’t perform well over sanding sealers since the sanding sealer prevents penetration. So, only use topical stain (like gel stain) over sanding sealer.
You also must sand the sanding sealer with fine-grit sandpaper before applying stain.