When to use oil or water based stain outside?

Staining: the basics

According to Aaron Barnett of BangingToolbox: Staining is the process of applying protective and decorative stains to a wooden surface. Wood stain is usually made out of three main ingredients – a binder, a carrier or solvent, and a pigment.

A wood stain helps enhance the look of timber’s wood grain [1], add color, and simply protect it from the elements, prolonging a wood’s life.

When choosing which stain to use, you’ll usually have to choose between water-based stain vs oil-based stain. There are a few differences, but both have the same general purpose. So which one to choose? Read on to find out!

Where to apply stain?

Before we go into the nitty-gritty of oil-based vs water-based stain, let’s first take a look at where stain should be applied.

There are a lot of benefits to staining that will ensure that your woodwork or outdoor wood has both a nice finish and enough protection.

Both stains are perfect if you don’t want to paint over wood and just bring out its beautiful and natural grain with a hint of color.

Some common applications of stains are:

• Wooden decks
• Wooden furniture
• Wooden cabinets
• Wooden trims
• Wooden ceiling beams

What is an oil-based stain?

So what’s oil-based vs water-based stain?

Oil-based wood stain is the original and most popular type of wood stain.

It’s well known for its high durability and high wood penetration depth that ensures that moisture is sealed out.

It is commonly made using linseed oil, a non-toxic oil and wood preservative that is then thinned by mineral spirits.

These spirits are petroleum-based solvents and have a strong and distinct smell.

Application of oil-based stains should only be done outdoors with good air circulation.

What is a water-based stain?

Water-based stain is a recent technological advancement in wood stain tech.

Water-based stain is easier to use, as it drys faster, and is more environment-friendly.

It uses water as a thinner instead of solvents which makes it have little to no smell in comparison.

While still protecting and coloring wood. Water-soluble aniline dyes are mixed in with the water-based stain. These are powdered dyes that bring out great color when dissolved in water.

An important thing to note when using water-based stain on the wood is to duly prepare the surface and make sure that it’s as clean as possible. Because it tends to dry quickly.

Advantages & disadvantages

Oil-based stain

When it comes to choosing between oil or water-based stains, it’s important to know the advantages and disadvantages of each type.

Water-based stain

When to use a water-based stain?

Use water-based stain if you want a colorful finish that still reveals the natural grain of the wood.

Wood, though can be durable, gets damaged over time and will eventually need repair.

When repaired, new-part replacements often cause mismatches in appearance and even coloration.

Water-based stains can help cover this up by effectively coating the surface in a uniformed color.

Water-based stains are better options for working indoors as they don’t smell and don’t require much help in drying, where less protection is needed.

When to use an oil-based stain?

Oil-based stains are perfect if you want high durability and low maintenance. They’re great for bringing out the natural appearance of wood as they are less opaque when used to color.

Oil-based stains penetrate deeply and lock out moisture from the wood which prevents it from rotting paired with wood tanalisation. If you want to stain structural wooden parts, go with oil-based stains to limit the need for regular maintenance as well as to avoid a more tedious pre-stain phase.

Comparing oil vs water-based stain

1. Finishing and appearance

Generally, oil-based stains are less impactful in terms of color but are better if you want to achieve a more natural brighter look.

In contrast, water-based stains are more vibrant and emphasized, but also make the wood look artificial.

The natural look of oil-based stains is a bonus if you’re using cedarwood because its finish mimics that of natural cedar oils.

2. Durability and performance

Oil-based stains are more durable than water-based stains because they penetrate deeper into the wood. This makes it highly resistant to light scratches and warping and nullifies most minor types of damage.

Water-based stains are prone to chipping and would need regular maintenance as it bonds to mainly just the surface of the wood.

So between oil-based vs water-based deck stain, you must now have an idea of what to choose.

3. On application and setting time

Water-based stains dry faster because they are thinner. However, to get a more even coat, it’s recommended to use a pre-stain wood conditioner so that the stain sets evenly on the surface.

Oil-based stains take longer to dry but adhere better.

Take care when applying oil-based stains when there are others as they are potentially toxic to pregnant women and children.

4. On maintenance

Since oil-based stains give a more natural look that ages with the wood, they are also easier to maintain and reapply.

Simply apply the stain on spots with chipping and discoloration, no stripping required.

In contrast, water-based stains are more tedious to maintain and reapply as you often have to fully strip the previous coat before applying a new one.

5. On longevity

Oil-based stains can last up to 3 years with minimal maintenance and retouching.

Water-based stains can last as equally long but are not as resistant to scratching and damage.

Knowing this is vital when you plan to stain wooden decks as such an application is sure to encounter frequent use and receives heavy wear and tear. 

Factors that affect the qualities of a stain

So what are the factors to consider when choosing water-based stain vs oil-based stain? Let’s find out.

Wood type

Choosing the kind of wood is important. Staining wood will show its grain, having an impact on its appearance which either complements or reduces aesthetics.

Cedarwood benefits greatly from oil-based stains as it mimics the finish of natural cedar oils. Avoid using wood with uneven or unsightly grain or ones that show any sign of rot.

Moisture

In the same way that water raises the fibers on untreated wood, high moisture levels [3] in wood that has been coated with an oil-based stain can suffer blotching and patching.

This is  because moisture may have a “balloon effect” just under the stained surface causing the stain to not penetrate as effectively. 

Previous treatment of wood

Before staining or re-staining wood, consider if it already went through treatment prior. Oil-based stains can easily be reapplied on pieces so long as they’re coated with the same wood stain type.

Water-based stains on the other hand require wood to 1st be fully stripped before applying again. Wood treated with urethane must also have the urethane layer stripped to allow the stain to better bond if at all. 

Weather

Weather is also an important factor when staining wood. Staining wood during a sunny day with low humidity ensures superior quality treatment.

Staining just after the rain or in relatively high humidity will affect the finish quality as it can possibly lock in moisture that not only leads to blotches.

But can also rot the wood from within, or cause timber movement.

So when it comes to patios or balconies, it is best to use oil vs water-based deck stain. 

How to prepare wood for staining?

Before staining, it is important to make sure that your target is smoothened. If you need to remove paint, here’s how.

Or consistent if you opt for a ruff sawn finish. Start with a belt sander armed with 100-grit sandpaper to even out the surface and remove milling marks.

After, do a second pass with a half-sheet vibrating sander and 140-grit sandpaper. At this point, the piece is ready for staining.

However, if you are planning to use water-based stains or want a smoother finish, do another pass with a quarter-sheet sander and 180-grit sandpaper.

Vacuum off the dust and make sure that the surface is clean and free from any particles that might get locked in.

And if you want to know if you can sand after staining, check this out.

Best time to apply an oil-based stain

It is best to apply oil-based stains on a dry and sunny day. This is to ensure that the moisture content of wood is low. And faster drying time to avoid a tacky finish. Refrain from staining wood in humid and wet weather.  Make sure that you stain in a well-ventilated area to avoid inhaling harmful fumes [4].

Best time to apply a water-based stain

Should you stain on wet wood?

As a general rule, wood should not have moisture content higher than 15% before staining. This is to make sure that the wood does not rot from the inside as staining will lock in moisture and whatever debris was left unremoved.

Oil-based stains, in particular, aren’t as good because of the fact that oil doesn’t really mix with water, thus leading to either a weak hold or a very uneven and discolored application.

But as a general rule set by the International Code Council or ICC, wood should have a moisture content of not more than 19% [5] before being coated with a wood stain.

It’s all a matter of choice.