Resin is a good choice for outdoor projects. It’s waterproof, durable, and won’t degrade from exposure to sunlight or weather. There are two types of resin that are used as coatings: epoxy and polyurethane.
Epoxy is a two-part mixture that cures to a hard, durable finish. While most resins cure to a clear finish, epoxy can be tinted with color pigments or mica powders to create opaque coatings if desired.
Epoxy has better chemical resistance than polyurethane and has better scratch resistance than the best varnishes; however, it doesn’t offer the same level of UV protection as polyurethane.
Polyurethane resin is usually called “casting resin” or simply “resin,” although it’s technically not an epoxy but rather a thermoset polymer that cures to a hard, durable finish.
Polyurethane resin comes in one-part formulas and does not need to be mixed with any other material in order for the chemical reaction necessary for curing to occur.
Polyurethanes do not offer nearly as much durability as epoxies do but they do provide better UV protection than most clear epoxies while allowing you to achieve finer details in your castings and molds since they will cure at room temperature within 24 hours (or faster if heat-cured) instead of requiring several days for complete curing as most epoxies do
How long will epoxy last outdoors?
Epoxy coating is an excellent option for many outdoor applications because it’s durable, easy to apply, and cheap. It’s perfect for small projects like a birdbath, or large projects such as your patio table. How long will the epoxy coating last outdoors? That depends on several factors:
- The type of epoxy resin you use
- How you prepare the surface before applying the coating
- How well do you apply the coating
- Where you live (in terms of temperature and humidity)
Table of Contents
Can epoxy be used outdoors?
Can epoxy be used outdoors? Epoxy is a good choice for outdoor projects. It can be used for coating and as an adhesive. Epoxy has several advantages over other types of coatings, such as acrylics and polyurethanes.
Does resin hold up outside?
Resin is not UV stable, which means it will yellow in the sun. The best way to protect epoxy is to make it more UV stable by adding a stabilizer.
The two most common stabilizers available for use with epoxy are benzophenone and hindered amine light stabilizers (HALS). This allows you to store your artwork outdoors or in direct sunlight with little risk of discoloration.
If you already have resin that has started to yellow, there are two methods for clearing up your original work:
- Use a special UV additive (e.g., Benzoflex 9-88) that reverses the reaction that causes discoloration. Simply add it as usual when mixing your resin. You can also mix it into resin that’s already set in case you want to protect a finished piece from further yellowing. However, this may shift the tone of blues, purples and greens so test on an inconspicuous area first!
Can epoxy be exposed to sun?
Although epoxy is UV resistant, it will eventually yellow in sunlight. In fact, most epoxies will yellow with exposure to ultraviolet light over time, regardless of whether or not the epoxy is clear.
This can be a problem for some people who are using the product outdoors, but if epoxy is used in a shaded area such as under a table or boat decking then it should be fine.
Will epoxy crack in cold weather?
Epoxy is a substance that will create a protective layer over the concrete you are using it on. It can withstand difficult conditions, so it is useful in places where there would be heavy foot traffic or high levels of moisture.
Epoxy creates a strong bond with concrete and typically doesn’t crack or peel when applied correctly.
It is possible for epoxy to crack if you do not follow specific steps before application. Many people worry about the temperature affecting the epoxy, as this can cause many other substances to crack. But with proper preparation, you don’t have to worry about your epoxy cracking due to cold weather. Here’s how:
- Allow extra time for curing
- Prepare concrete surface
Does epoxy yellow in the sun?
You are correct, epoxy yellows over time because of the UV rays. This is called photodegradation and it causes a lot of problems for things that need to be stored outdoors for long periods of time.
The way you prevent this from happening is by adding a UV stabilizer to the mix. There are specific, formulated uv stabilizers that epoxy manufacturers add but you can also use an additive called Cab-O-Sil M5 to get the same effect if you want to do it yourself. It’s cheap, easy, and works great!
If you can’t find any kind of UV stabilizer then make sure your epoxy project is stored under some sort of covering or shaded area. This will help with keeping your project intact longer and give it more life without yellowing.
How do you protect the sun from epoxy?
The sun can be a relentless enemy for any paint product, even epoxy. Because epoxy is typically clear and shiny, the ultraviolet rays from the sun are not filtered by the epoxy’s coating like in traditional paint.
The sheer power of these UV rays can cause epoxy to lose its shine or even turn a yellowish color over time.
There are several ways to protect your epoxy:
- Cover it with a UV resistant clear coat
- Use a resin that is UV resistant/has UV inhibitors
- Paint over the epoxy (you will still need to use a UV-resistant paint)
- Use an Epoxy that has built-in UV protection
- Use a sealer with U/V inhibitors
- Should you choose to topcoat your finished project, consider using one of the many coatings available which have built-in U/V inhibitor protection.
Which coating is the most tolerant to outdoor exposure?
While the term “epoxy” is used pretty generically in the marketing of many products, there are several different types of coatings that can be labeled as epoxies. Most epoxies are two-component systems made up of a base resin and a curing agent.
They can be cured with heat or by catalyzing with another chemical, but for outdoor protection, you will want to use a UV curable coating. You might see this referred to as:
UV cured epoxy
UV cured resins
UV cured coatings
UV curable coatings
UV curable resin
UV curable epoxy
UV resistant epoxy
Conclusion
So, as you can see, epoxy can be used outdoors. But, you need to make sure that it’s protected from the sun and cold weather.
The best coating is one with UV protection. Make sure that you let the area thoroughly cure before exposing the finished product to the elements. Do your research and follow the coating manufacturer’s instructions for best results.
