Those getting into refurbishing might leap to action before really researching the distinct types of stains and their differences. When re-finishing a product, it is important to discern whether the original finish was water or oil-based, as water and oil products do not adhere well to each other.
How can you tell if a stain is water- or oil-based? We’ve created a simple guide to help you understand the main differences between water- and oil-based stains, the products they are best suited for, and how to test products to see if they are water or oil-based finishes.
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Once you learn about the differences in application, color, and appearance of water and oil-based stains, you may be able to tell by looking at a stain which it is. However, if you can’t, we’ve provided some easy-to-perform tests that will quickly reveal the nature of the stain in question.
How to Test Whether a Product Was Made with Water Based or Oil Stains
When starting to restore a product made of wood, you’ll need to test for whether the wood was stained with a water-based varnish or oil-based varnish. This is necessary because each kind of stain requires a different style of removal and re-application. Also, water-based stains do not combine well with oil-based solvents.
If you mistakenly apply the wrong stain on top of an opposite finish, you won’t be happy with the result. It may not ruin the wood, but it will certainly not render the desired effect you’re going for. Not to mention the potential waste of time and money you might incur.
Below are some simple tests to help one determine if a stain is a water- or oil-based. These are tests that can easily be tried at home, due to the likelihood you already own some of these materials, and if not, they are easy to source at your local grocery mart or hardware store.
Test 1 – Sprinkle Water
Since oil-based stains are relatively water-resistant, an easy test to determine the kind of stain on any given product is to sprinkle little droplets of water onto the stain area. Wait and see if the water beads up. If the water does bead up, then the stain in question is oil-based.
Test 2 – Apply Goo-Gone or Other Such Solvent
Goo-Gone and similar cleaners are amazingly effective at cleaning water-based surfaces without pulling away any color or damaging the stain. However, Goo-Gone will lift color from oil-based stains. If the stain is oil-based, when you apply Goo-Gone (via a towel) and rub on a wood stain for a bit, you will notice the rag has become dirty and likely that the wood you’d been rubbing down is lighter. This is because the stain formerly applied was oil-based, and the Goo-Gone is lifting the stain off.
Test 3 – Alcohol Application
Using a cotton ball or soft tissue, apply alcohol, and wipe the alcohol-soaked cotton ball or tissue along the wood product. Notice what happens on the places where the alcohol was applied. If the alcohol dried and in its place the wood is slightly lighter in color, it indicates that the stain was water-based. Conversely, if the alcohol doesn’t react at all, no color is removed, then you can bet the stain is oil-based.
Test 4 – Touch it!
By far, the simplest method, though its results won’t wow like pulling color off a varnish the way Goo-Gone will. However, it is none-the-less effective. Simply feel the stained area with your bare hand. Oil-based stains feel exceptionally smooth to the touch than do water-based stains. This is because oil-based stains sit atop the wood more so than do water-based finishes. Water-based stains like acrylic and polyurethane seep deeper into the wood rather than sitting on top of it.
Why is it Important to Test for the Type of Stain?
As previously mentioned, you cannot put a water-based stain on top of an oil-based stain and vice versa. They do not adhere well together. You won’t like the look, and you’ll have to spend more time and money having to re-do the stains.
Once you’ve established what kinds of stains you are working with, then you can shop for a stain of that kind (whether water or oil-based) that will match up with the stain style you’re going for.
If you are going to strip a piece of furniture down raw and start completely over, then you have the option of picking any kind of stain. For those embarking on this kind of varnishing adventure, we’ve provided you with a list of key features for water- and oil-based stains to aid you in your decision making.
The Differences Between Water-Based and Oil-Based Stains
Now that we know how to test for water-based or oil-based stains, it’s important that you understand the differences between the two, how they are applied, what the consistency is, how they look, and how chemically resistant they are.
For an in-depth explanation of the differences and similarities between water-based and oil stains, watch this video.
It can be somewhat difficult to tell the difference between water-based products like acrylic and polyurethane. However, there are some important chemical differences, and they do appear only slightly different from one another. It is in their chemical make-up that determines what these two different water-based stains ought to be used for.
- Consistency: Acrylic stains are thicker than water-based polyurethane, and less thick than oil-based stains.
- Liquid Appearance: While many acrylic varnishes appear white, they do dry clear.
- Application: Acrylic stains are quite easy to apply. Water-based acrylic stains are quick to dry, typically within two hours.
- Finish: Acrylic varnishes appear glossy, with a very natural look. They bring out the natural depth of timber without changing its overall hue or appearance.
- Uses: Acrylic stains are an excellent choice for those projects that need to be finished very quickly, due to the ease of application, speed of touch-dry, as well as the shorter cure time (as compared to oil-based products.)
- Odor: Very minimal amounts of odor
- Cure Time: Acrylic stains take 5-7 days to cure.
- Chemical Resistance: water-based acrylic stains are relatively chemical resistant and can withstand most food and alcohol stains. However, they are not as chemically resistant as a heavy-duty polyurethane.
- Clean Up: brushes can easily be cleaned with water
Polyurethane (Heavy Duty) Varnishes
- Consistency and Appearance: Heavy-duty water-based products like polyurethane stains tend to be a watery, clear liquid which also dries clear.
- Application: Polyurethane stains are also easy to apply. Heavy-duty water-based products made of polyurethane dry faster than acrylic. The typical dry time is around one hour.
- Finish: Polyurethane varnishes dry with a crystal-clear finish and provide a totally natural timber finish. It dries ultra-hard, which is why it is labeled as ‘heavy duty.’
- Uses: Polyurethane heavy-duty stains are ideal for both commercial and domestic products. They are especially ideal for areas that are high use, such as wood floors, worktops or desks, bars, and dining tables.
- Odor: Very minimal amounts of odor
- Cure Time: Polyurethane heavy-duty stains take around 16 hours to set and cure.
- Chemical Resistance: Heavy-duty products have much higher chemical resistance. For this reason, they are extremely good for areas where they’ll be exposed to products like food stains, juices, alcohol, etc.
- Clean Up: brushes can easily be cleaned with water
- Consistency: They are thick like sap, but dry clear
- Liquid Appearance: Oil-based varnishes have a golden brown/yellow appearance
- Application: Unlike water-based stains, oil-based varnishes take much longer to apply due to their thicker consistency.
- Finish: Oil-based stains provide a brighter finish. They deepen whatever timber they are applied to, creating more depth and vibrancy. Oil-based stains provide a deeper brown, slight yellow hue. The downside to using oil-based stains is that, unfortunately, oil-based varnished do grow yellower and yellower over time.
- Uses: Due to the long application process, longer drying time, and long cure time, oil-based products are ideal for projects that have zero-time constraint and are more ‘appearance’ important than durability/speed. Many people who use oil-based use it because it wets the timber better than do water-based stains, which is what gives an oil-based finish that attractive deep shine.
- Odor: Has more of an odor, it would be wise to wear a mask while painting with an oil-based stain.
- Cure Time: Much longer cure time than water-based products. Oil-based stains take 14 days to cure fully.
- Chemical Resistance: still relatively chemical resistant, however, not as resistant as a heavy duty polyurethane would be.
- Clean Up: Brushes that have been used to apply oil-based stains should be immediately washed to prevent the brush from being ruined. Oil-based products require more than just water to be thoroughly cleaned. People often turn to turpentine to clean oil-based stains.
The Key Take Away?
Water-based and oil-based stains are fundamentally different. It is essential you know which stain was used on a piece of furniture before you attempt to refurbish it. Conducting a few simple tests will reveal what type of finish was used, so you can use the correct varnish moving forward.