How Thick Can I Pour FlowCast Epoxy Resin?

Maximum pour thickness for single pours or pouring multiple layers for a thicker epoxy product

When using epoxy resins, it is important to understand that when the two parts of resin (Part A) and hardener (Part B) are combined, it creates a chemical reaction that produces heat during the curing process. For this reason, it’s very important to control the temperature and follow the instructions on the labels whether you’re using our FlowCast® or any of our other epoxies.


For EcoPoxy FlowCast®, our maximum recommended thickness per layer is 1.5 inches. This recommendation is under the assumption that:

  • The room temperature is stable between 65-75 degrees F
  • You have a fan set up on your project to cool it during the cure
  • The volume of your pour is less than 20L




For a pour less than 20L (5gal), a 1.5” layer should cure fine without overheating but for pouring more than 20L, we recommend breaking it up into multiple layers of about 1” per layer to avoid overheating. Keep in mind that FlowCast® is not recommended for pouring anything less than 1/2 inch. If you are pouring less than 1/4" thick, check out using UVPoxy instead or you will likely need to apply heat to the FlowCast® to help it cure properly.


Pouring Multiple Layers for a Thicker Epoxy Product

If your epoxy pour is too thick, the reaction can create too much heat, resulting in a product that does not cure properly with cracks or excessive bubbles. You can pour the next layer after the previous pour has gone through its heat cycle, which is usually around 24 hours. The rule of thumb is if you can make an imprint with your fingernail in the epoxy you can pour again and the epoxy will chemically bond to the previous layer. If you’ve passed that point, sand the surface of the previous layer with 180-220 grit sandpaper. This creates a rough surface for the next layer of epoxy to stick to. Once sanded, clean the surface with an alcohol-based cleaner like de-natured alcohol to remove all the dust from sanding. After that, you’re good to pour!