Is epoxy completely waterproof? More than once, I’ve heard from people working on projects, be it a boat, a patio, whatever… that end up complaining because they have been told that epoxy is this miracle product that will prevent any type of corrosion or damage. That it is essentially bomb-proof. My first question always runs something along the lines of “are you sure you were using an actual epoxy product?” As in, “this isn’t some cheap knockoff product pretending to be epoxy, right?” And for the most part, people get that part of the equation right. But the bigger picture, and this extends far outside the realm of epoxy is that the tools are only as good as the artist allows them to be. What does this mean? Well, it means that the epoxy has to be applied properly. Epoxy is waterproof, end of story. But one hastily mixed, sloppily applied coat of epoxy might give you some issues. So, assuming you’ve bought bona-fide epoxy, what can you do to ensure that you end up with waterproof epoxy? You can follow these simple steps:
1. Read the directions. The big thing to take away here is the mixture ratio. Some epoxies, like many System Three epoxy products are mixed at a 2:1 ratio. That is, two parts resin, one part hardener. Others call for a 1:1 mixture. Screwing this up will have a very detrimental impact on your epoxy’s performance, so double check this before you get started.
2. Once you’ve confirmed the mixing instructions, make sure to mix the two parts thoroughly. You’ll likely be using some kind of Dixie-style cup and a Popsicle stick. Make sure to spend a solid 45 seconds stirring your compound. Scrape the sides of the cup as you go to ensure both parts are completely mixed before you move on to the application phase.
3. Apply the epoxy uniformly, and don’t be careless. That means trying to distribute the epoxy evenly over your surface, and don’t miss any spots. If you’re a little short, it’s always better to mix up a little more than it is to just resign yourself to a super thin coat in a couple of spots.
4. Apply more coats. Don’t assume that the first coat is going to do it. Wait however long the directions indicate for the first coat to completely cure, and then repeat steps 2 and 3. Three solid coats should do the trick on most surfaces, and should ensure that you have a very solid, waterproof epoxy solution for your project.
I linked to System Three above, and here is the product that I recommend to most people looking for a top-notch waterproof epoxy: