Is Resin Waterproof? – We Tested 4 Resins to Find Out

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Using Resin for crafting and woodworking has been getting increasingly popular over the years. So I was wondering what resin could be used for. I started by researching if resin could be used for projects involving water and I conducted my own test to see if and what types of resin are waterproof.

Resin is waterproof and can be used to glue or coat items that will have contact with water. But resin doesn’t cure while in contact with water, so only cured resin is waterproof. All types of resin, including UV resin, liquid resin, resin paint, epoxy putty, and resin glue are waterproof.

There are resins specifically made for waterproofing pools and boats like marine resin, for example. These resins are specially formulated to adhere well to any surface and waterproof most surfaces very well even when applied in thinner layers.

But what about other resins like art resin, deep pour resin, epoxy putty, and UV resins? How waterproof are they and can they be used to waterproof air-dry clay or glue a broken mug? Well, let’s find out by doing some hands-on tests.

Is Resin Waterproof?

Resin is generally waterproof but I want to find out how waterproof resin generally is.

So I tested four different resins by cutting some holes in a couple of cubs and then I tried fixing them with the resin.

If you don´t know what resin is or if you want to know more about resin then consider reading this article where I explain exactly what resin is and what kind of resins there are.

Art Resin

Art resin is mostly used for making jewelry or for coating art in a thin layer of resin to protect it.

Like most resins, this resin comes in two parts (the resin and the hardener) that have to be mixed in a specific ratio before pouring it.

Art resin should not be poured in layers thicker than 5 cm or 2 inches or it might deform. So we have to see how waterproof art resin is in thin layers.

Resin can´t adhere and properly cure on wet or dirty surfaces so we have to make sure that the surface is dry and clean before pouring the resin.

The art resin did prove to be waterproof and not a single drop of water went past it even after leaving the cup filled with water overnight.

Deep Pour Resin

Deep pour resin also comes with a hardener that needs to be mixed with the resin in the right ratio before pouring it.

Deep pour resin can be poured in thicker layers and is often used for making fake water or for pouring river tables.

You can read a full guide on how to make fake water and how to properly use deep pour resin in this article.

This resin can be poured in thicker layers and should therefore be more water resistant than other liquid resins.

I colored the deep pour resin green so that I can keep it apart from the rest but that doesn´t affect the resin in any way.

The deep pour resin turned out to be waterproof as well. I left the cup filled with water stay overnight and not a single drop was spilled.

Epoxy Putty

Epoxy Putty comes in many different colors and is used for many different things. The two most popular Epoxy Putties are probably Green Stuff and Epoxy Putty from Gorilla.

Even though epoxy putty isn´t exactly the same as epoxy resin it is similar enough that I wanted to test how waterproof it really is compared to resins.

Epoxy putty also comes in two parts and they have to be kneaded until they are properly combined with each other. Then the putty is applied to the broken mug and let there to harden for a couple of hours.

I plugged a hole that I put in the bottom of a cup with some epoxy putty, let it dry, and then filled it with water.

And it turns out that epoxy putty is just as waterproof as all the other resins on this list. I left some water in the cup overnight and the hole was plugged water tight with the epoxy putty.

UV-Resin

The last resin on my list is UV-resin.

UV-resin is the only resin, that I know of, that does not need a hardener to cure. Instead, it cures when it is exposed to UV rays.

UV-resin is especially useful for coating small areas in resin and quickly fixing holes or cracks.

I cut a small hole on the bottom of the cup and fixed it with some UV resin. Then I filled the cup up with water and left it sitting for a night.

UV-resin is also waterproof and can be used to fix holes permanently. No water was spilled and from all of the options listed in this article, the UV-resin was by far the fastest way.

How Long Before Resin is Waterproof?

Resin won´t instantly make anything that it is applied to waterproof. Resin needs to properly cure before it is waterproof. But how long does it take before resin is waterproof?

Resin is waterproof as soon as it is fully cured. Depending on the type of resin this can take anywhere from a couple of minutes, when using UV-resin for example, to 72 hours. It is, however, recommended to wait up to 12 hours longer than Instructed to ensure that the resin has cured completely.

A good indicator of when the resin is done curing is when it is no longer warmer than its surrounding.

Resin cures in an exothermic reaction meaning it will produce heat during the curing process. Once the process is done and the resin is completely cured the exothermic reaction will stop and the resin will cool down to a normal temperature.

Resin paint will usually take longer than art resin to cure and UV resin is able to cure in minutes when exposed to UV rays.

Is Hardened Resin Waterproof?

Fully Hardened resin is waterproof but resin will not cure correctly when it is in contact with water during the curing process. So only hardened resin is waterproof and resin should not come in contact with water before the resin has completely cured.

This is also why resin can´t be used to fix a leak while there is still water running.

You have to dry everything around the leak, then apply the resin, and then wait for at least 72 hours before exposing the resin to water.

Does Epoxy Make Wood Waterproof?

I love using epoxy resin for my woodworking projects. It can create amazing effects and it can be used as a finish. But does epoxy make wood waterproof?

As a whole, epoxy does make wood waterproof. It can be applied as a coating to protect the wood from scratches and liquids or it can be used to encase a wooden piece in epoxy. Either way, it will make the wood waterproof once it has cured completely.

Epoxy is often used as a finish for table tops, kitchen tops, and more to protect the wood underneath it from water, dirt, and scratches.

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