Buying guide for best epoxy resin coatings
Epoxy resin coating is perhaps best known as an alternative to traditional varnish. It seals and protects all kinds of materials, including wood, stone, ceramics, concrete, and more. It’s more forgiving and more durable than varnish once it’s dry (cure), too.
Epoxy resin can also be used for casting anything from jewelry to entire worktops. It can encapsulate small items, it can be stained, and it can even be used to create unique decorative effects. There’s a creative element as well as protective when it comes to epoxy resin coatings.
There are lots of different products to choose from, and many of them sound very similar, so it can be tricky to choose the right one for a particular job. We’ve been investigating the properties of each and have recommended several that showcase the variety of solutions available. We’ve also put together the following buying guide, which looks at the important aspects in more detail.
Key considerations
How an epoxy resin coating works
An epoxy resin coating is a two-part product: a resin and a hardener. In this case, the resin is basically a clear synthetic polymer (a kind of plastic). It remains liquid until it’s mixed with the hardener, and then it cures at air temperature until solid.
The curing time varies. A few types take as little as 24 hours, but many require several days. The result is a deep, lustrous, often crystal-clear finish that can be very hard. Depending on the product, it might also offer good resistance to heat, scratching, and even cutting.
If you’re applying a protective finish, you may only need a single application, though more artistic and thicker pieces might require numerous thin coats of the epoxy resin.
Choosing the right epoxy resin coating
It can be difficult to decide which product is right for your project. The individual characteristics can be very similar. They are all very hard when cured. They all claim to offer a glass-like finish. Almost all of them claim to be self-leveling (to avoid brush or other tool marks). Many are degassing, which means they expel any air bubbles that might leave blemishes on the surface. How true this is varies from one product to the next, and you should expect to do at least some work. Almost all of them include ultraviolet inhibitors to prevent yellowing.
As you shop, look for things that distinguish one product from another.
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Quality: This is a major factor, but it can be difficult to judge unless you’ve been given a recommendation. If there are a lot of customer reviews — dozens or hundreds rather than just a few —that can be useful.
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Preparation: This is usually fairly straightforward as long as you measure the quantities carefully, though application varies. Beginners might want to look for those products that have a reputation for being easier to use.
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Coverage: This is important, so you know how much epoxy resin coating you need. Manufacturers usually tell you the number of square feet a container will cover at a given thickness. Just know that you might have to do some math!
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Work time: This might be an issue. If you have a large surface to cover, you need time to smooth it out and remove any air bubbles before it starts to harden. You usually get about 30 minutes, but it can be up to an hour for some products.
- Safety: Look for a product with zero volatile organic compounds (VOC), which are dangerous to the respiratory and nervous systems, kidney, and liver.
Epoxy resin coating features
Color
It’s worth checking to see whether the epoxy resin coating is actually clear to begin with. Some have a yellow tint.
If you want to dye your epoxy resin, whether giving it a translucent or solid color, you need to know the pigments available and how effective they are with a particular product. Staying with the same brand should guarantee compatibility.
Quantity
Pack size can be slightly misleading. A gallon kit doesn’t give you a gallon of resin and a gallon of hardener. It provides a total of a gallon of ready-to-use coating. While most mixes are one to one, some are three to one.
Type
There’s a difference between casting resins, those intended for craft projects in which you build up considerable thickness, and what are often called “tabletop” epoxy resins, those intended as a protective finish. There are some hybrid products that can be used for both, though casting depth will often be limited. Good manufacturers make it clear what their product should be used for, but it’s important to read and understand the description before buying.
Note: Don’t confuse polyester resin coating with epoxy. The former offers neither the protection nor the durability.
Accessories
Although some people use a heat gun (or even a hair dryer), professionals tell us the most efficient way to get rid of bubbles in epoxy resin coating is with a butane torch. It also burns off any surface dust, further improving the finish (and it’s pretty good for creme brulée, too!)
Ordinary brushes can leave marks and drop hairs into the resin that will ruin your work. A foam brush is a cheap alternative that doesn’t cause these problems. This set of 1-, 2-, and 3-inch brushes suits all kinds of projects.
Accurate mixing is vital for a high-quality epoxy resin finish. These 8-ounce plastic cups are dishwasher safe and handy for a variety of household tasks. You get 20 for a low price, too.
Epoxy resin coating prices
Inexpensive: Although it’s generally cheaper to buy larger quantities, you can find 16- and 32-ounce containers for between $20 and $60.
Mid-range: There are a few 2-gallon kits at just over $100, which represents a great value (around $50 per gallon), though your outlay is obviously greater.
Expensive: Most epoxy resins from leading manufacturers cost around $80 to $100 per gallon and pro rata if you buy more.
Caution
Don’t put uncured resin or hardener in the trash. Pour it onto paper, let it cure, then dispose of it normally. Do not burn waste epoxy resin; it can release hazardous chemicals.
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Tips for applying epoxy resin coatings
It’s imperative that you follow the manufacturer’s instructions. Some also have useful videos to help you. Here are a few general suggestions.
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Prepare well. Dust and dirt are the enemies of a glass-like finish, so make sure the environment you’re working in is as clean as possible. Don’t use resin immediately after sanding. Vacuum and then leave the shop overnight so any airborne particles can settle.
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Protect other surfaces. Wax paper is excellent for protecting any areas you’re not working on.
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Monitor the temperature. Check the manufacturer’s suggested temperature range. Working outside this range will affect flow and curing times.
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Apply resin up to the maximum thickness. Don’t be tempted to exceed the stated maximum thickness.
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Glue down small items. If you’re encasing small items, make sure they’re properly glued down. If not, they could start to float in the liquid.
- Don’t use a spray gun. Unless you’re an experienced professional, don’t use a spray gun to apply resin. The epoxy resin is very difficult to clean out and could ruin the mechanism.
FAQ
Q. Are epoxy resin coatings toxic?
A. It depends on the manufacturer. Craft products designed for home use may not be. You’ll generally see a comment like “certified nontoxic when used as directed.” Many commercial products in liquid form are considered “irritants” and can cause mild to severe breathing problems (and potentially asthma) depending on exposure. We recommend that you always wear a breathing mask, gloves to avoid skin contact, and protective glasses to avoid splashes. Many of these resins in liquid form are toxic to aquatic life. However, once cured, they are classified as nonhazardous.
Q. What do I use to clean the mixing jugs afterward?
A. Always use plastic/polyethylene containers, because the two components don’t stick easily. Wear latex or rubber gloves. Wipe out as much as possible with kitchen towels, then use acetone or rubbing alcohol. If you let the product dry, soaking it in either of these solvents should eventually break it down. Dispose of cleaning products responsibly.
Q. What is the shelf life of an epoxy resin coating?
A. It varies from product to product, but you can expect at least 18 months for some types, a couple years or more for others (the resin often outlasts the hardener). If you’re concerned about whether old epoxy is still viable, just mix up a small batch in a plastic cup and see if it cures. The thing most likely to cause a problem is cross contamination, which means tops or plungers can get stuck. Sometimes running them under warm water can help free things up.
