Can you stain over polyurethane? You must be wondering! Here’s what you need to know…
Whether you can apply stain over polyurethane is a question that a lot of woodworkers have so you are not alone.
I’d like to let you know that though it’s not a common practice; you can apply stain on polyurethane; the stain must be gel stain.
The gel stain does not penetrate like a stain; hence you won’t get the same grain patterns.
The gel stain is more like opaque paint. So, if you want to change the color without stripping, then gel stain is what you need.
Polyurethane is an excellent finish for that wood fence, table, or piece of furniture you have been working on.
Most people prefer to use it as a coat after applying stain as it protects your wood from scratches or water penetration that may damage your wood.
Staining over polyurethane is possible but with some conditions. Read on as this article gives you more information on how best to stain on top of a polyurethane finish.
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Types of Wood Stain
Staining your wood is an exciting activity you can do after finishing the construction of your structure.
While staining is not mandatory, you may need to do it if you want to protect your wood projects from unnecessary damage.
Besides, staining your woodwork will also give you an attractive appearance, not to mention the aesthetic angle you will also achieve.
Also, note that wood stains often contain chemicals that may be dangerous to your health; always remember to take the necessary precautions while applying it.
But what exactly is this wood stain? A wood stain is a liquid, powder, or gel applied to protect your wood surface. It comes in various types, which are discussed below:
- Oil-based wood stain. Oil-based wood stain is the most common stain woodworkers use. It is preferred because of its deep wood penetration and durability.
Linseed oil with varnish is a common component in an oil-based stain. Linseed oil is a non-toxic and natural oil that works best to maintain your wood finish or your pain.
You can easily distinguish your oil-based stain from others because of its thinning by mineral spirits.
You will most likely find mineral spirits in your wood stain description, listed as ‘petroleum distillates.’ The mineral spirits are a solvent used in manufacturing an oil stain.
Depending on the manufacturing company, synthetic pigments are also common in some oil stains. Iron oxide and dyes, also referred to as wiping stains, are common synthetic pigments in oil stains.
Oil stains for commercial purposes contain a ‘binder’ as a third ingredient. The binder, any kind of resin, helps bind the pigments to a wood surface.
Linseed oil is the most used binder. It is treated with several special acids, which prevent it from penetrating your wood surface deeply.
Although it goes unsaid, many manufacturers add a thickening agent to oil stains. The agent, just like the acid, is used to control an oil stain penetration.
Be sure to confirm the ingredients when selecting an all-natural oil-based stain. Doing so informs you of the stain’s compatibility with your wood.
It takes 2-3 hours for your oil stain to dry up, after which you can add another coat. Wait for 9-10 hours, then apply your wood finish. A
Also, remember to dry your stain under room temperature for the best results.
- Water-Based Stain. Rather than organic thinners, a water-based wood stain often uses water. Water stains are present in the stain, adding color to your wood. The stain is often formed from powdered chemical dyes from coal and tar.
The water-based stains stain high-quality pigments which enhance the grain of your wood.
Water-based stains are so eco-friendly that they contain less polluted particles. Water stains do not emit any volatile organic compounds.
Applying water-based stain is simple; clean your wooden surface, smoothen it with sandpaper, and you will be ready to apply the first coat.
A water-based stain dries up more quickly compared to an oil stain. It also gives you excellent wood protection as they don’t penetrate deeply into the wood.
The water-based stain’s con is that it will consume most of your time.
Use a water-based stain when working on hard to work on wood surfaces like birch, pine, or oak.
- Lacquer Stain- Lacquer stain is mainly used by professional woodchoppers. It is commonly used because of its quick-drying properties.
Lacquer stains are formed with xylene and ketones, making them dry faster than other stains. The two elements are mixed, forming a pigmented lacquer.
Despite the quick-drying ability, the xylene and ketones elements produce a strong odor. Therefore, when working with this stain, always wear a protective mask to avoid inhaling it. The xylene and ketones elements penetrate the woods; thus, you will only need a maximum of two coats.
The disadvantage of the lacquer stain is that staining may cause bubbles on your wood surface, which won’t look very attractive.
However, you can minimize the bubbles by drying the stain at a wood temperature or using a thinner.
Choose a lacquer stain if you need your staining quickly done and if you are a professional. It also works best on wooden floors.
- Gel Stain- Gel stains are either oil-based or varnish-based. They have a high viscosity and thick pigments. Despite being messy, gel stains will create a splotch-free coat, making it a time-consuming option. Gel stains have been in the market since the 20th century.
The high viscosity nature of a gel stain limits its penetrating ability. On the positive, this feature makes it possible for application on permeable and non-permeable timber.
Work on a well-ventilated space when using a gel stain. Also, wear protective gear to avoid damage or injury to your body.
Test the stain on a small wood surface for sampling.
Metalized Dye Stain. When using bare woods, metalized dye stains are the best. They are formed by blending glycol with ethanol and methanol. This stain will give you a good color depth.
Metalized dye stain is ready for the used type of stain and is found in concentration form. It is easy to thin the metalized dye stain by using water, alcohol, or lacquer thinners.
Use a sprayer to apply the metalized dye stain.
A damp cloth is also effective when evening out this type of stain.
- Varnish Stain- This is an oil-based stain but forms a finishing layer like a polyurethane varnish. The stain will give your furniture a consistent texture and color.
With a varnish stain, you can also use petroleum distillate as a thinner.
Unlike other types of stain, you only need a varnish coat, and your furniture is fit. The single layer is enough to protect your interior wood from damage.
The oil stain uses varnish as a binder or a polyurethane varnish, a synthetic resin. Polyurethane is heat resistant and thus has properties to resist chemical and acid spills.
The varnish stains will dry out on your wood surface, thus increasing your furniture’s durability.
The biggest drawback of using a varnish stain is that it can still look splotchy and will require more coats to even it out.
Varnish stains are recommended when working on small projects or your wood surface is already stained.
Use a roller or a brush to apply the varnish stain. Apply it in the direction of the wood grain.
- Water-soluble dye stain. This stain is unique as it is only found in powder form. The powder is mixed with water and then used to stain interior wood, wooden furniture, and floor. Use one quart of water to mix with one ounce of powder.
Use more powder for a deeper color. Also, use distilled water. Regular water may leave a residue that will alter the color of your stain.
The water-soluble dye stain does not conceal your wood, regardless of the amount used.
Also, note that the stain is flexible as it doesn’t have a binder. You can easily make it dark or light after staining your wood surface.
Unfortunately, the water-soluble dye stain has a short life span. It will fade with time.
For best performance, use your water-soluble dye stain with hot water.
How to Stain Over Polyurethane Wood (Using Gel Stain)
Staining your wood allows you to enhance its natural color and grain. However, you may feel that your polyurethane strain is worn out or not as attractive as you want.
Luckily, you can apply gel stain on your polyurethane by following the following process:
- Disassemble all fittings and accessories on the wood piece you want to stain. Dismantling your project enables you to reach the tricky area easily. It also helps prevent staining on areas you don’t want to stain.
Drop cloth or old newspaper to protect your floors from spills in a well-ventilated area. Measure your working surface with masking tape to ensure the stain will not spill out of place.
- Clean your surface by removing any grease, grime, or dirt. Use a degreaser or warm soapy water for the cleaning. Ensure that you rinse off any soap residue on your polyurethane. Cleaning is vital as the grease, grime, or dirt will impair the adhesion of the gel stain to the polyurethane.
Dip a scourer into your warm soapy water to scrub the area you wish to stain. Rinse the area with clean water and allow it to dry for at least two hours.
- Create a rough surface through sanding. Sanding provides a surface profile on the polyurethane, which will enhance the gel adhesion. Use sandpaper with fine grit on a sanding block to sand the polyurethane surface.
Use sandpaper without a block in more complex areas.
All you need is light sanding; therefore, avoid heavy grit sandpapers. Using heavy grit sandpaper may scratch the polyurethane surface.
Use a tack cloth to remove dust particles and also any grit. You can also use a damp, lint-free cloth instead of a tack cloth. Wait for your surface to dry up, then proceed to the next step.
- Before applying your gel, test it on the part of your wood that is not easily visible. Testing it helps you to determine whether the gel color is what you wanted or not.
Wear gloves before applying to protect your hands from staining.
Apply the gel to your piece of wood, one area at a time. Use a cloth or an applicator pad to wipe your work surface.
Generously spread and smoothen your gel until you achieve your desired look.
Start the application with a thin layer. If the stain doesn’t give you a desired dark color, apply a second coat after the first layer dries up.
Depending on your manufacturer’s instructions, allow your gel stain to dry up for approximately 24 hours.
How to Stain Over Polyurethane With a Gel Stain:
Mistakes to Avoid When Using Gel Stain
The steps discussed above are essential in your gel stain application. However, beginners in the woodwork are likely to run into common mistakes which are time-consuming and costly.
This section discusses some of the most common mistakes when using gel stains.
Sanding is a vital step in preparing the wood surface you want to stain. The process removes any imperfections in your work area by opening up pores.
Failing to sand will prevent the penetration of your gel stain, resulting in a messy finish.
Not Testing Your Gel Stain Before the Actual Application
Test staining is crucial as it allows you to decide whether the gel shade is what you want or not. Sample colors provided on your gel manual may not be accurate.
Fully staining without a sampled test may leave you greatly disappointed. Ensure you carry a piece of wood to your purchase store, which allows you to test the stain before buying.
Poor Disposal of a Cloth or Applicator Pad Used In Applying the Gel Stain
Failing to dispose of the cloth used in painting properly is dangerous. You are generally recommended to use the gel stain a room temperature because of its ability to generate heat.
If the stain on the drag dries due to heat exposure, it may result in a fire hazard. Always place your cloth or applicator pad in a metal container with a lid or a plastic bucket partially filled with water.
Not Apply Wood Conditioner Before the Gel Stain
Failing to apply a wood conditioner before your gel stain application may result in streaks and blotches. To avoid this and achieve a uniform color after staining, use a wood conditioner.
Ignoring the Excess Stains or Spills On Your Wood
Since gel stain is oil-based with a high viscosity, the stain dries off slowly.
Failure to wipe off the excess stain will make the stain tack and blotchy in appearance. You will need mineral spirits as they are the most recommended solvents.
Working with a badly damaged wood
Gel stain will not fix the deep scratches, missing veneer pieces, or old water stain. Always fix your damages before applying gel stains in any of the mentioned cases.
Using a Lighter-Colored Stain
Rather than using a lighter-colored stain, use a darker one because the darker it is, the more perfectly it will conceal your imperfections. Use a gel stain darker than your original color when staining over poly.
Sanding Against the Wood Grain
Sanding against the wood will leave scratch marks on your wood which will show through your gel stain. While preparing the surface you want to work on, apply light sanding, working in the same direction with your wood grain.
Using Coarse Sandpaper or a Powder Sander
Coarse sandpapers will also leave scratch marks on your polyurethane finish. The sand powder may also sand down the top coat and the bare wood, leaving you with undesired results.
Applying Thick Coats of Gel Stain
Using thick coats of gel stain may take hours or days to dry up. The thicker the gel stain, the longer it takes to dry off.
Besides, the thick layers often appear uneven with patched coloring. You don’t want this on your finished work, do you?
Also, avoid applying a second layer of the gel stain before the first layer dries up. Ensure that you have wiped off the excess stain to achieve even coverage.
Can You Stain Over Water-Based Polyurethane?
Yes, it is possible to apply wood stain on top of water-based poly. You only need to be specific on the type of stain you use. Gel stain is the most recommended.
For perfect compatibility, ensure that the stain is water-based and not oil-based.
Before staining over the water-based polyurethane, scuff sand the surface with fine-grit sandpaper or a sanding pad.
Can You Use Oil-Based Stain Over Polyurethane?
No, we highly advise against using an oil stain over a polyurethane finish. The oil stain will only work by wiping off the polyurethane, erasing even its color.
An oil-based wood stain often seeps into the wood. However, the polyurethane coat won’t allow the oil-based stain to penetrate through it.
You could maneuver around the oil-based stain on your poly if you mixed the stain with poly. The mixture would allow the oil to stick to the existing coat.
Alternatively, use products such as the Minwax poly shades as the manufacturers professionally mix them before packaging.
Factors to Consider When Staining Over Polyurethane
There are essential factors to consider when staining over a polyurethane-finished surface. Find out below what you need to do for a perfect finish on your woodwork.
- Woodgrain. We have severally discussed the wood grain. Since the polyurethane is clear colored, it will show even the most minor stain marks over the coat. Following your wood grain direction when staining over a poly finish is always important.
Pay attention to the wood grain to follow and disguise any marks that remain after a staining process.
- The wood stain color. The dark color helps conceal any imperfection from your refreshed stain. Use a stain with a color darker than your existing finish.
If your stain is not dark enough, return it to your store for a darker shade. You won’t regret this.
- Wood stain adherence. A standard wood stain will not adhere to a coated surface since polyurethane often acts as a barrier. Wiping off the excess stain is a recommended practice in your staining procedure. However, if you have used a standard wood stain, you will wipe it all off. This will cost you your time and money. We don’t want such a loss!
Instead, use a gel stain by following the methods discussed above. Alternatively, use a combination of poly and stain (ready for use from the manufacturer). The two options will smoothly adhere to the existing finish.
Lastly, remember to scuff up the surface using fine-grit sandpaper to enhance adhesion. Polyurethane wood can be annoyingly glossy.
Are you sick and tired of that old piece of furniture and would like to give it a new lease of life? You can use different approaches to achieve that feat. One question however is…
Can You Stain Over Polyurethane?
Yes, you can stain over polyurethane without stripping the existing finish into your bare wood. You can add gel stain over the polyurethane finish and achieve the look you desire on your furniture.
This article gives you step-by-step guidance on how you can apply your gel stain over a polyurethane finish. We have also outlined the common mistakes woold workers commit when applying the gel stain.
Alongside the mistakes are solutions and preventive measures to avoid them. Also, consider the factors discussed in the article for the best results after staining on polyurethane.
I like to think that you can do just about anything with the gel stain! Including its application over a water-based polyurethane.
Hopefully, you will successfully apply your gel stain over the polyurethane after reading this article. Enjoy as you try it out.