If you’ve got an inconsistent pour or just want to avoid bubbles in a deeper epoxy project, you may consider layering coats of epoxy resin. But before you try to epoxy over epoxy, you might hesitate because you don’t know if this will adversely affect the project.
You can epoxy over epoxy if you sand the bottom layers after they cure and then pour subsequent coats of epoxy resin. This is a time-consuming process but reduces the risk of trapping bubbles in a deep-resin project.
In this article, you’ll learn everything you need to know about applying epoxy over epoxy, including the different things to keep in mind, how the practice affects the overall project, and different methods to go about it.
Epoxy Over Epoxy Best Practices
Epoxying over epoxy is possible, but it should not be taken as ideal under all circumstances. First of all, you have to judge the feasibility of applying multiple layers of epoxy based on the desired result.
If you have a dyed epoxy resin project and the goal of resin is to be an opaque, shiny layer that has an aesthetic effect, then a scratched coat of epoxy resin or surface imperfection can be fixed by a second layer.
In such a repair job, the second layer of epoxy is supposed to be more opaque than the first layer or must be poured thicker than the first coat. Consequently, the actual surface imperfections underneath are hidden.
More apt use of pouring multiple layers is when the first layer is not consistently thick horizontally. In other words, if one area of a flat surface has a thicker layer of epoxy and the rest of the surface doesn’t have the same thickness, you can either sand down the more viscous pour or bring up the depth of pour across the rest of the surface.
Sanding can be problematic, especially if the glossy finish is what you want out of epoxy. That’s self-evident because sanding can dull the finish by affecting the actual coat that preserves the epoxy from getting UV damage and from getting scratched.
How Deep to Pour Epoxy for Multiple Layers?
Considering the utility of multiple epoxy layers, you still cannot pour a perpetually thick stack of epoxy. That’s because any layer that goes over 1/8 of an inch is playing with fire.
If you pour epoxy thicker than 1/8 of an inch, you will almost certainly get bubbles because air bubbles are natural in the chemical reaction that occurs during the curing of the epoxy. And if a layer of resin is thick enough, it will trap the bubbles.
So your only solution really is to work in a hot enough environment that the bubbles pass through easily and to lay a coat thin enough to allow bubbles to pass through entirely before it is cured. And once it is cured, you can apply the next layer. Hence, the coats are applied in increments of under 1/8 of an inch.
How to Prepare for Epoxy Over Epoxy?
Please do not test your pour and its depth on the main project. This should go without saying, but you must have a separate work area, a separate surface, where you measure the depth of your pour.
To do this, you need first to get a stopwatch and clock your pour on a timer. It is tempting to start by having a mark at one eight of an inch and then pouring until the resin reaches the mark, And then seeing the time. While that can work, it introduces a distinct setting that will not be present when you’re working on the main project.
After all, you’re not going to have a marker that you’re constantly watching. To truly get the time you must spend pouring in order to get 1/8 inch thickness, you must measure the time while pouring casually without constantly watching any markers.
Time your intuition and adjust it until your pour is the right amount. It will take little time and will hurt a little as some precious resin will go to waste. However, it will save your final project.
Pour without regard for any markers on your test project or your test surface, and just estimate what 1/8 of an inch looks like. Alternatively, if you have worked with resin before and have not have had trouble with trapped air bubbles, you already pour less than 1/8 of an inch per coat. You can skip time-adjusting your pours because you don’t need to figure out how much time it takes; all you need to do is pour thin layers the way you usually do.
Drawbacks of Epoxy Over Epoxy
The next thing to remember is that with every added layer, the stakes are even higher because the third or the fourth layer of epoxy resin can trap air bubbles and mess up the entire project wasting all the time it took for the rest of the layers to be laid and to cure. This is why the initial pours are crucial. The first or the second layer being too smooth can lead to the upper layers getting destabilized and chipped off the project.
To avoid this, you need to account for two things: first, every subsequent pour is thinner than the initial pours, just to be careful that it does not trap any air bubbles. Second, that all layers except the final coat are not smooth. It’s better if every coat that gets poured over is not smooth and can have the roughness to which the next layer holds on. This brings us to sanding.
Best Practices for Epoxy Over Epoxy
Sanding is crucial when you’re laying multiple coats of epoxy on a vertical level because the higher the number of coats stacks up, the more the smoothness of the lower levels affects the stability of the higher layers.
After you have poured the first layer of epoxy, you must wait the entire time it takes for the resin to cure. Once it has cured not just to the touch but to functional perfection, You move on to the sanding process.
You take a sanding block or a coarse sanding paper-like product and sand away the surface. Then you pour a well-mixed coat of the same resin over the initial layer. It is crucial to work with the same resin unless there is an artistic benefit to going out of your way and choosing different resins. This ensures that stacking layers of epoxy doesn’t lead to unstable coats.
Even for artistic reasons, I would recommend working with the same epoxy and albeit with different pigments instead of working with different epoxies altogether. As long as the project has the clarity or color you want, and each layer is stable enough not to impact the project’s longevity adversely, you don’t need to worry about this too much.
There are certain advantages and disadvantages to using this method, and you must understand them because there also exists an alternative. It is to simply get a deeper pour epoxy resin, work in an extremely hot environment, and pour it much deeper than you would a regular epoxy resin.
Pros and Cons of Pouring Epoxy at Once
The advantages of a thicker pour are that you don’t have to spend as much time waiting for the epoxy to cure, though you might still need to work with multiple (yet fewer) layers. The next key benefit is that you don’t have to be as consistent with each pour because you’re most likely laying a single coat, and as long as you’re consistent once, you don’t have to worry about the second pour matching the consistency of the first one.
Pros and Cons of Epoxy Over Epoxy
Most artists prefer to work with multiple layers of epoxy because, first of all, you don’t have to work with a special kind of epoxy resin that is suited for deeper pours. This is cost-effective. The second advantage of having multiple pours is that it gives the artist more control and time away from the project.
Thirdly, it reduces the risk of bubbles significantly because one is working with far fewer, far shallower layers. It also reduces the need for heat even though you still have to work in a hot environment. Finally, it allows the artist to fix mistakes, whereas a deeper pour resin has to be poured the first time perfectly.
The drawbacks of applying epoxy over epoxy are that if you do not know what you’re doing, you might waste expensive epoxy resin material. Laying layer after layer while none is cured will either cause air bubbles or result in a project that remains perpetually uncured. Read this article to know how to get rid of epoxy that hasn’t cured.
The other disadvantage of applying multiple layers without knowing what you’re doing is that you might apply the topcoat. In contrast, the bottom layer is not rough enough to hold on to the epoxy beneath. This is especially the case if the epoxy resin has a high gloss finish. Most epoxy resins cure smoothly with a clear finish, making them bad surfaces for subsequent coats unless sanded properly.
But the method covered above includes sanding, and if you do it well, this disadvantage doesn’t apply. Almost all drawbacks of stacking multiple coats of epoxy vertically come from not doing it properly. As long as you apply the steps in this post, you will get all the advantages of laying epoxy over epoxy without the drawbacks.
Applying multiple coats of epoxy resin isn’t anything new. As a long-established practice, it has its well-known dos and don’ts. The golden rule that sums up the practice is as follows: you must wait for a layer to cure before sanding it and pouring the next coat.