Collection: Primaloc Epoxy Blog

An image of an orange question mark with a green background and two text overlays, one that says "Primaloc Answers" and another that says "Epoxy Curing Phase FAQs"

Primaloc Answers: Epoxy Curing Phase FAQs

From beginning to end, an epoxy project involves several primary phases. Each phase can be divided up into smaller steps, which in turn have their own set of instructions to complete. This is all to achieve a perfect finish with the epoxy resin.

Depending on the type of epoxy project, the phases involved will vary. Not all projects go through every conceivable step—only those that are needed.

For instance, the three primary phases of a countertop epoxy project are:

  • The Seal Coat Phase. This phase involves a thinly brushed-on layer of epoxy resin to "seal" the surface and forcibly release air from pores, cracks, and microscopic grooves.
  • The Flood Coat Phase. This phase includes the main application of epoxy. A larger batch is prepared and poured onto the substrate surface.
  • The Curing Phase. This is the least interactive phase, primarily involving waiting. But there's more to it than may be immediately apparent.

In this article, we'll be addressing frequently asked questions about the curing phase of epoxy resin. This phase is perhaps the least understood; when not handled properly, a variety of different issues can come up.

Thankfully, the curing phase is easy to understand once you have the right information.

Epoxy Curing Phase FAQs

The curing phase of the epoxy process occurs at the end; it is the final phase of a project. Though it is mostly hands-off, there are still various things you can do to ensure it turns out as clear and strong as possible.

Here's a list of the questions we answer this time:

  1. How Long Does Epoxy Take to Cure?
  2. How Can You Make Epoxy Cure Faster?
  3. Can You Dry Epoxy With a Hair Dryer?
  4. How Long Does It Take Epoxy to Cure on Wood?
  5. Will Epoxy Bond with Cured Epoxy?
  6. How Long Does Epoxy Take to Dry on a Cup/Tumbler?
  7. Can Epoxy Cure in Hot Weather?
  8. How Do You Cure Epoxy in Cold Weather?
  9. How Do You Fix an Epoxy Finish That Did Not Cure?
  10. Is Epoxy Food Safe?

We'll cover these questions one-by-one, starting at the top of the list.

A set of wooden epoxy kitchen countertops.

Question #1: How Long Does Epoxy Take to Cure?

On average, epoxy will take about 72 hours for a strong cure.

Here's a rough timeline:

  • After 4 Hours: You can apply an additional coating.
  • After 10 Hours: You'll need to lightly sand before applying an additional coating.
  • After 24 Hours: The epoxy is gently usable. This means you can perform further project modifications as needed, but don't use it like you would if it were fully cured.
  • After 72 Hours: It will be 99% cured, given the right environmental conditions were maintained.

Keep in mind that epoxy types vary, with some curing faster than others. We recommend you consult your epoxy's instructions for the most precise information.

Epoxy has a peculiar trait through which it actually continues to harden well past the 72 hours mark. Think about 72 hours as being the 99% cured point. For the next few weeks or even months, the epoxy will slowly finish curing to 100%.

In most cases, that extra percent is negligible, but it does mean that your epoxy finish will be even stronger months after you've completed it.

Question #2: How Can You Make Epoxy Cure Faster?

There aren't any reliable shortcuts to making epoxy cure faster.

Attempting to forcibly speed up the curing process can cause many issues. Though it can be frustrating to have to wait it out, the curing process is best left to itself, undisturbed as it continues to completion.

That being said, you can ensure that the cure finished on time by providing the ideal conditions for curing:

Keep the Relative Humidity to 60% or below.

The moisture from high humidity can affect the epoxy's ability to cure promptly. Though cured epoxy is waterproof, uncured epoxy isn't, and the humidity can condense and cause problems to the curing process.

Maintain a temperature of about 75°F.

Epoxy cures best at around 75°F. This temperature facilitates the curing process. Some epoxy resins can handle a wider range of temperatures (e.g., 60°F to 80°F), but all of them cure well at 75°F.

Remove Air Bubbles After Pouring Your Epoxy.

Removing air bubbles can help the epoxy settle quickly to cure. This step is performed just after pouring, and is easily accomplished with a heat gun or torch.

These three tips will not only ensure optimal curing rates, but they're also essential for achieving that crystal-clear, rock-solid finish.

A set of dark wooden epoxy countertops.

Question #3: Can You Dry Epoxy With a Hair Dryer?

You should never use a hair dryer to speed up the epoxy curing process. It is better to let the epoxy cure naturally and evenly throughout.

When epoxy cures, it generates heat that is then dissipated into the space around it. Using a hair dryer interferes with this process, and because hair dryers naturally apply high force even at their lowest settings, they have a strong tendency to induce air bubbles into the epoxy resin.

You also should never use a hair dryer to remove air bubbles.

Question #4: How Long Does It Take Epoxy to Cure on Wood?

In appropriate conditions, epoxy on wood will be lightly usable after 24 hours, and it will take 72 hours to cure to a fully usable state.

Question #5: Will Epoxy Bond with Cured Epoxy?

Yes, epoxy resin can be applied to previous layers of epoxy, cured and partially cured.

For cured epoxy, you'll first need to sand the surface. We recommend something between 220 grit and 300 grit for this.

When a fresh layer of epoxy is properly applied this way, the finish should retain its clean, transparent appearance.

As for uncured epoxy, you can apply additional layers to a coating 4 hours after the previous one. If more than 10 hours have passed since the previous coating was applied, you'll need to do a light sanding for that before pouring the next layer.

Question #6: How Long Does Epoxy Need to Cure on a Cup/Tumbler?

24 hours is the usual amount of time we recommend people allow for epoxy cups and tumblers to fully cure.

Question #7: Can Epoxy Cure in Hot Weather?

Yes, epoxy can cure in hot weather. The ideal temperature, though, is 75°F.

However it is important to note that higher temperatures can cause the epoxy to cure too quickly and may lead to uneven curing with blemishes. If possible, avoid temperatures above 85°F when working with epoxy.

Question #8: How Do You Cure Epoxy in Cold Weather?

Though epoxy won't cure in cold weather, you can provide suitable curing conditions by constructing a temporary enclosure with controlled heating.

One way to make a temporary heating enclosure requires the following:

  • PVC. This will form the framework for your enclosure.
  • Painters Plastic. This will provide coverage for your enclosure.
  • Duct Tape. This will keep the enclosure sealed.
  • Space Heaters. One or two of these is enough to generate heat within the enclosure, allowing your epoxy to cure.

Get enough of each material to fully enclose your epoxy project, then construct it, place in the space heater(s) (in some cases you may also need a power extension cord to reach an outlet.

Once your enclosure is set up, just turn on the heat and try to maintain that optimal 75°F for an excellent cure.

A set of marble epoxy countertops.

Question #9: How Do You Fix an Epoxy Finish That Did Not Cure?

Sometimes epoxy doesn't cure right. This is most often due to inadequate mixing, but it can also be caused by incorrect proportions during measuring.

In cases like this, the epoxy will either be solid/sticky or soft/wet. Here's how to deal with each of these.

To Fix Solid and Sticky Epoxy

To restore a solid, sticky epoxy finish, you should just apply a new flood coat over it. Read the instructions for your brand and carefully follow them to achieve a clean result. Then give your epoxy adequate time to cure, and it should look as intended.

To Fix Soft and Wet Epoxy

Fixing soft, wet epoxy is more involved. You'll first need to remove the soft material, as much as is possible. A knife, paint scrape, etc. are all useful tools for doing this. If needed you can apply a bit of denatured alcohol or acetone to make things easier.

Aftery you've remove any soft epoxy, simply apply a new flood coat over the previous one, while carefully following the instructions for your chosen epoxy brand. If handled correctly, you'll end up with a clean, transparent finish.

Note: Sometimes, there may be multiple soft spots that are more significant. In this case you can mix up a small batch of epoxy after clearing them out a bit, fill them and give your finish 4 hours to partially cure. After that, you may apply a new flood coat to the entire project.

Question #10: Is Epoxy Food Safe?

Yes, once cured, epoxy is considered food safe.

Keep in mind that this doesn't mean epoxy is a good surface to prepare food on. Knives can cut it and excessive heat greater than 135°F can cause heat damage/softening.

But contact with food is not a problem for cured epoxy. The best thing you can do to ensure you have no issues it to choose a high-quality epoxy resin from a credible source.

Primaloc Epoxy: Premium Epoxy for Premium Results

When it comes to epoxy resin, Primaloc Epoxy gets the job done. Our epoxy resin is premium-grade, with high performance in every category.

Epoxy resin can be beautiful, strong, and long-lasting—which is why you shouldn't compromise on quality. With Primaloc Epoxy Resin, you get the ultimate finish in durability and visual appeal.

Protect your surfaces by giving them a rock-solid epoxy finish. Choose strong. Choose reliable. Choose Primaloc.


Previous Primaloc Highlights: Epoxy Resin Art
Next Primaloc Epoxy Basics: How to Clean Resin Cups and More