Sanding sealer is often a shellac or lacquer formula that is applied over porous and uneven wood before applying a top coat. But can you put sanding sealer over wood stain?
You can use sanding sealer over existing stain only if you want to put a top coat or clear coat on the sanding sealer. Since sanding sealer seals the wood pores, putting regular stain or penetrating wood oil over the sealer will not work.
You should also know that you can’t use sanding sealer as the final coat. It’s also generally recommended to sand down the sanding sealer before applying top coat. This is to remove blemishes and imperfections in the sanding sealer coat.
So do you use sanding sealer before or after stain? Let’s take a closer look.
Do You Use a Sanding Sealer Before or After Stain?
Generally, sanding sealers are designed to be used before applying stains. The sealer coating is made to help stains stick and adhere better to poor wood.
But sanding sealer can also be used after stain and this should only be done if a top coat would be applied over the sealer coating. Painters also use sanding sealers after stain when they want to apply multiple coats of a topical stain like gel stain.
Sanding sealers are usually lacquer or shellac-based coatings that help stains to adhere properly to rough, porous, and uneven wood. Sanding sealer also helps to seal porous wood to prevent the wood from sucking stain excessively.
The sealer should be applied on bare wood that doesn’t accept stains properly. If the wood is riddled with patches or it doesn’t stain evenly, painters apply two coats of sanding sealer on such wood. The sealer is a pre-stain conditioner meaning that it makes the wood smoother and ready to accept stain.
However, sanding sealers can also be used after stain if you would put a top coat over the sealer coating. For instance, if you want to clear coat over an existing stain, you can apply sanding sealer over the existing stain to prep it for the clear coat. You should know that sanding sealers should be sanded with 320-grit sandpaper before applying the top coat. This is to make the top coat stick better.
You shouldn’t put sanding sealer after stain if you want to apply a penetrating oil stain on the sealer coating. This is because the sanding sealer will prevent the oil stain from penetrating the wood as it’s supposed to. Oil-based stains should be applied to bare wood. The best type of stain to use over sanding sealer is a topical or non-penetrating finish.
Does Sanding Sealer Stick To Stain?
Sanding sealer sticks well to stains because the sealer coating has a formula that allows it to stick to virtually any type of surface.
Since sanding sealers are designed to be used on poor surfaces, the sealer coating has already been designed to adhere well regardless of the type of surface. Also, wood stains usually don’t have any ingredient that will repel the sanding sealer.
However, you should know that sanding sealers might not stick well to oil-based stains as these stains form a glossy sheen when dry that prevents anything from sticking.
This is because the texture of the glossy sheen will be slick and difficult to stick to. To put sanding sealer over an existing oil-based stain, you’ll have to remove the gloss first.
How Long Should Stain Dry Before Sanding Sealer?
On average, you should let stain dry for 4 hours before putting a sanding sealer over it. This gives the stain enough time to dry and harden enough to support the sanding sealer coat.
You should let the stain dry enough for a re-coat before putting sanding sealer over it. The time it takes for the stain to dry enough for sanding sealer depends on the type of stain and drying conditions.
You should know that it’s not advised to put sanding sealer over fresh regular stain. Regular stains like oil and water-based wood stains should not be applied if the goal is to put sanding sealer over them.
You are only allowed to put sanding sealer over regular stain if the stain is already on the wood and you want to apply a new stain over it. In this case, the sanding sealer will help the new stain adhere properly and the existing stain being old will be more than dry enough to accept the sanding sealer.
For top coats and clear coats, however, you can apply sanding sealer over a fresh coat as long as the coat is dry enough. On average, this takes about 4 hours. Thick top coats like gel might take up to 6 hours to dry enough for sanding sealer.
Next, let’s find out how to apply sanding sealer over stain easily.
How To Apply Sanding Sealer Over Stain?
Applying sanding sealer isn’t hard and 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
- Always ensure the stain is dry enough for recoat before applying 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 a 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)
Here is a 5-step guide on how to apply sanding sealer over stain:
1. Check If The Existing Stain Is Dry
The first step before applying sanding sealer over stain is to check if the stain is dry enough to recoat. If the stain isn’t, applying sanding sealer will turn into a disaster as the sealer coat will not dry. The pigments in the damp stain will also stain the sanding sealer.
To know if the existing stain is dry enough for recoat, run 320-grit sandpaper over the stain. If the sandpaper doesn’t move freely, then the stain is not ready for a recoat.
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 after applying the stain for it to dry enough for sanding sealer.
2. Sand The Existing Stain
The next step is to sand the stain. You should do this with a fine-grit sandpaper. The purpose of sanding is to remove bumps in the stain.
Sanding also helps to create ridges in the stain that the sanding sealer can bite into for proper adhesion. You shouldn’t sand aggressively as doing that can remove the stain completely.
After sanding, there will be dust nibs on the surface. You should remove the dust with a clean rag to make sure the surface is smooth.
3. Apply The Sanding Sealer
The next step is to apply the sanding sealer. Usually, one coat of sanding sealer is enough since you are applying it over a stain but you can apply two coats if you want to switch 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.
However, ensure to only apply thin coats. You should also ensure to cover the surface evenly so the new stain can also be absorbed evenly.
4. Scuff The Sanding Sealer
When the sanding sealer is dry, it needs to be scuffed or sanded before staining. This is to remove blemishes and tiny imperfections on the sanding sealer. These imperfections can prevent the new stain from sticking well to the sanding sealer.
Also, if you would be putting a transparent or clear coat over the sanding sealer, these blemishes will show through the clear coat if you don’t sand.
You should use sandpaper of at least 200 grit over the sanding sealer. Coarse and medium-grit sandpaper will remove the sanding sealer. After sanding, you can remove dust and apply the stain.
Can You Apply Stain Over Sanding Sealer?
You can only apply a topical stain over sanding sealer. You should never apply regular wood stain over sanding sealer because the paint will not stick properly regardless of whichever trick you try out. Here is why.
Stains are generally penetrating finishes. This means that wood stains when applied need to penetrate the wood pores to stick well and change the color of the wood.
On the other hand, a sanding sealer, as the name connotes, is a sealing coat. What this means is that sanding sealer when applied will seal the top layer of the wood making it impossible for moisture to penetrate.
Since stains need to penetrate to stick well, applying stain over sanding sealer that allows no penetration will lead to a disaster.
If you do this, the stain will not stick well and will turn sticky and smell foul for days. This is why only topical stains can go over sanding sealer.
Topical stains like gel stains don’t need to penetrate the wood to stick like regular stains. As such, these stains will go over sanding sealer perfectly. Some water-based stains and clear coats can also go over sanding sealer because water-based stains don’t penetrate wood as deeply as oil-based stains. But you’ll need to sand.
Can You Mix Sanding Sealer With Stain?
It’s not a good idea to mix sanding sealer with stain. This is because both products have different formulas and ingredients that are not compatible.
Also, both products shouldn’t be mixed because they have very different functions. Stains are designed to penetrate wood and change the color of the wood grain. Sanding sealers are designed to prevent penetration so mixing both products mean that they will get in each other’s way.
If the sealing property of the sanding sealer is what you require for your wood stain, you can apply a sealant over the stain when it dries. Sealants like polyurethane, varnish, and lacquer can be applied over wood stain and they all offer impressive sealing qualities that are even better than sanding sealer.
In summary, you can use sanding sealer over stain but you have to apply a top coat over the sanding sealer as sanding sealers can’t be used as the final coat.
You should also remember that penetrating finishes and regular wood stains don’t perform well over sanding sealers since the sanding sealer prevents penetration. So only a topical stain like gel stain should be used. Lastly, ensure to sand the sanding sealer with fine-grit sandpaper before applying stain.