Frequently Asked Questions

• As a preventive measure we recommend to work with resins warmed up to their working temperatures. This would help to maintain the viscosity in the range specified for the product and ensure optimal air release. 
• Lower than optimal working temperature will increase the viscosity and worsen air release properties.
• Epoxy mixing should be done in such a way as to minimize the air entrapment. If you use drill mixer, choose the rotation speed such that no vortex occurs when mixing. 
• All the manipulations with resin, such as pouring, adding pigments, swirling should be done within specified working time. 
• Large slabs of wood have the air entrapped in pores in voids. When the wood is not sealed, then the air will try to escape the moment you pour your Casting Epoxy. This can leave visible bubbles inside your cast. Seal your wood before pouring Casting Epoxy.
• After mixing epoxy resin and hardener, you may want to use degassing chamber for the projects with advanced shapes and requirements. 

There are few reasons why the epoxy wouldn't cure as expected. Knowing these scenarios in advance would help you to avoid the timely and costly mistakes.

• Mixing ratio

Epoxy mix ratio should never be changed. Epoxy resin and hardener molecules have active sites that were designed to react with each other. If the mix ratio is followed properly, then resin and hardener molecule build a solid matter where all the molecules reacted with each other.

The mix ratio is affected if there are more hardener molecules than the resin ones. Not every hardener molecule will be able to find a corresponding resin molecule to react with, thus leaving some of the hardener molecules not fully reacted. This scenario affects the quality of the molecular network and properties of the cured epoxy, such as hardness and glass transition temperature. 

A similar effect occurs if there is a scarcity of hardener molecules in the mixture. Reaction cannot be complete; thus, cured epoxy will experience lower than ideal properties.

• Temperature

Epoxy will start experiencing problems with solidifying if it is used in ambient conditions significantly below the recommended working temperature. The reaction will slow down after the gelling point and remain incomplete. It is also possible that the chemical reaction will not even start if the ambient temperature is too low. Please see the diagram below to get an idea of the behavior of epoxy systems.

• Volume of the pour and project dimensions

Visit our Coating Epoxy Basics and Casting Epoxy Basics to learn more about the volume and dimensions of the epoxy pours you can do with our products. 

• Proper mixing techniques

Proper mixing is essential for good curing. Mix Part A and Part B for 5 minutes scraping walls of the mixing pail from time to time. If epoxy is poorly mixed, there will be clusters of only resin molecules and only hardener molecules with no pair to react with. Obviously, this would lead to poorly cured material with mediocre properties. 

Epoxies can be described as liquid materials maintaining liquid properties below freezing point. Unmodified epoxy resin can stay in a liquid state for a long time. Still, freeze/thaw cycles or impurities could cause the epoxy to crystalize and become soft white solid matter. In this case, epoxy can be heated up to 55°C and become liquid again without losing any properties. Our epoxies are formulated to be crystallization resistant. All of them have passed the ISO 4895 test for crystallization resistance. It is highly unlikely for you to experience problems with the crystallization of Nerpa Epoxies.

Curing time of the epoxy resin depends on the type of the epoxy used, ambient temperature, shape and volume of the pour. Visit our Casting Epoxy basics and Coating Epoxy basics to find information about cure behavior of our products. 

Nerpa Epoxy is not biodegradable. Decomposition of fully cured epoxy under normal conditions is not happening. This allows epoxy to be used in many industrial applications such as protective coatings and lets your project stay as nice and shiny as when you just made it, even after several years of use. If our epoxy was made to be biodegradable, sunlight and microorganisms could have started the process of decomposition of your project the moment you made it.

The food safety of an epoxy resin is a complex question. We decided to dedicate a blog post about it which you can find here.