What To Do About Thick Epoxy

       I’m sure you’ve heard the old saying: “if some is good, more must be better.” Unfortunately, this couldn’t be further from the truth when it comes to pouring epoxy resin. 

       It may seem like simple math to mix the volume of epoxy needed for your project and just pour all at once. But if you pour more than directed, your work has only just begun.

The Short Answer

       Mixing and pouring too much epoxy can cause an accelerated chemical reaction that will produce too much heat, and with it, unwanted results – to say the least. The simplest and most effective way to avoid problems is by paying close attention to the instructions and following them precisely. In the event that you do encounter those pesky imperfections, our go-to advice is to sand away imperfections and repour in thin layers, only 1/8″ – 1/4″.

  • Mistakes happen! Read our related articles on several other epoxy resin mistakes to learn how to fix them AND avoid them the next time around!


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Tacky Epoxy

Uneven Epoxy

Cracked Epoxy

Fish-eyed Epoxy

The Long Answer

       It’s never a good idea to pour thicker than your instructions recommend. Remember how the process works: epoxy cures due to a sensitive exothermic reaction. Unfortunately, that means that if even a little too much heat is added, this reaction will be accelerated. This can easily cause the epoxy to form more bubbles, cracks, fish-eyes, turn yellow, or even start smoking!

       To minimize this room for drastic error, modern technology has allowed for the development of two different types of epoxy resins systems for the two main categories of epoxy resin projects.

       The first type is a system called Casting Resin. The other type of system is called Table Top Epoxy, or sometimes coating Epoxy.

  • Remember all epoxy resin kits come in a system of two parts: the liquid resin and the hardener!

       Because resin is a substance that generates heat upon itself, we recommend pouring in 1/8″ layers only. This lowers the volume of liquid epoxy per cubic inch, which prevents overheating.

Easy Example:

    • To explain this concept in simpler terms, think of penguins huddling in the antarctic winter in an effort to generate heat as a group – the heat generated depends on the number of penguins.

       The shallow pour of a layer also allows more bubbles to escape because they reach the surface quicker!


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Salvaging Flawed Epoxy After a Thick Pour

       Some flaws can’t be fixed, which is why it is so important to mix and pour correctly from the start. 

       However, flaws that occur near the accessible surface can be salvaged. Our recommendation is to sand down until the imperfection is gone, then pour again – properly.

Repairing Imperfections At Surface Level:

Excess heat will cause the epoxy to expand, which will shrink as it cools – and then crack!


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1. Thoroughly sand away the imperfection with a sandpaper grit within the 160-320 range. Sanding with too fine a grain will make the surface too smooth to bond with the next layer of epoxy.

Sand away the flaw – a low grit like 220 will do just fine

2. Use a clean, lint free cloth or an air compressor to remove the dust. Then, after ensuring to follow the instructions carefully, mix and pour a new layer of epoxy over the surface of the whole piece.

Repour over the project completely, not just the damaged spot. This leaves a seamless look, with no evidence of one formerly damaged area.

       If there are many flaws visible inside of the piece, you must first evaluate whether or not these imperfections impede the project’s structure or strength. It is then your choice to scrap the piece, keep as is, or make an attempt to salvage what you can from it. 

Repairing Imperfections Inside The Piece:

Some imperfections just might add a bit of character!


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1. Remove the flaw completely. This can be done by using a saw or a grinding tool, like a dremel. The saw would be used to cut along both sides of the imperfection and remove that section of the piece entirely. The dremel would simply be used to grind out the flaw, leaving a hollowed out crevice. 


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2. Sand where needed and remove the dust, either with a lint free cloth or an air compressor. Then, again after carefully following the instructions, mix and pour new layers. This will fill either the crevice, or the gap between the two halves which have been laid in a dam. For further details on this step, refer to our other article: How To Pour Epoxy Layers

3. Pour another layer to coat the entire piece and leave a seamless finish.

Understand The Difference –
Casting Resin vs Table Top Epoxy:

       Now that you’ve gotten your repair work done, let’s review the main difference between Casting Resin and Table Top Epoxy, or coating epoxy. Knowing what makes these two products different is vital when choosing epoxy for a project. Using either for just their specially designed purposes will help to avoid big complications and/or flaws in your work.

Casting Resin vs Table Top Epoxy:

       Table Top Epoxy, as the name suggests, is specially designed for coating projects. Typically poured in 1/8″ and 1/4″ layers, coating epoxy is perfect for covering things like countertops, bar tops, or even floors!


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     Casting Resin used for pouring into molds of varying thickness and shape, to make casts like decorations, jewelry, and paperweights.


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     To learn more details about the differences between Casting Resin and Table Top Epoxy, read our related article here: Epoxy vs Resin | Casting vs Coating!

Do It Right The Next Time:

       Here are a list of preventative measures worth taking to avoid flaws the next time around!

       –  Read your instructions. Then read them again. Intentional or not, deviating from instructions is the most common cause for imperfections.

       – Before pouring, always level your piece. This ensures reliable, even results.

       – Pour thinner layers. You’re sure to have learned by now that epoxy is a temperamental thing. While this means increasing the number of pours, it also means greatly reducing the risk of a thick layer overheating and forming imperfections. We say the extra effort is worth it.

       – Use a short and wide cylindrical container for preparing the resin and hardener, this makes thorough mixing easier and reduces the heat build up in epoxy. This is in substitute to a taller, narrower, cylindrical container.

       – Reduce the temperature of the working environment. Epoxy is meant to be poured at about room temperature, and we don’t recommend lowering it below 65 degrees. However, whatever the temperature, do your best to keep it stable and consistent. Fluctuation in temperature can cause more imperfections.

       – With the temperature control in mind, be sure to cover your piece. Find a way to prevent dust and debris from contaminating the epoxy surface during working and curing.

       – Use Deep Pour coating Epoxy. This will help avoid layers overheating when accidentally poured too thick.

Recommended Supplies:

       Time to take what you’ve learned and get to work. Our goal with this article is to have empowered with the information to go forward and get creative with your epoxy. To make choosing supplies a little easier, we compiled some of the top rated online options.

     Here are the popular picks for some of this article’s items:

  • [link – top rated casting resin beginner’s kit]
  • [link – top rated table top epoxy beginner’s kit]
  • [link – top rated deep pour epoxy]

… etc


       So now you know what happens when you pour epoxy too thick – and what you should do about it! Don’t cry over spilled epoxy. Take a breath and evaluate your work to determine if you can salvage it. If so, carefully remove the imperfection. Then, follow the instructions correctly and re-pour epoxy onto your project, layer by layer. Soon enough, you’ll have yourself a beautifully completed epoxy project.

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