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.
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.

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!

Low temperature.FlowCast® will need more time to cure if your room temperature is lower than the recommended range of 68-77 degrees Fahrenheit or if it was applied too thin, FlowCast® is not recommended for pouring anything less than 1/2 inch. Applying heat to the project may help it finish curing. Luckily, there is no window of time for curing that can be missed, so even if your project has been sitting in a cool room for weeks and hasn’t fully cured, taking it indoors or warming it up will allow for the curing process to complete.

Off-ratio mixing.There may have been too much or too little hardener, which directly affects the cure time of the batch.

Insufficient mixing.You may not have mixed long enough for the resin and hardener to be adequately mixed for a proper cure. Always mix thoroughly for a minimum of 5 minutes.

High humiditycan also cause product curing issues, we do not recommend pouring at humidity levels higher than 75%.

Getting your Epoxy to cure Faster:

The best way to speed up the cure is by adding heat to the area that your project is in. Every 8C can cut the cure time in half. If the epoxy is heated too much, though, it can cure too quickly and may crack or bubble excessively.

Thinking about keeping a finished epoxy piece outside? Weather conditions can alter the look of your project. Here are some points to know before you decide to keep the piece outdoors.

Sun and UV Exposure:
All our woodworking epoxy products (both FlowCast and UVPoxy) cure to a crystal-clear finish when used without pigments. UV exposure will discolor all epoxies over time, making the piece yellow and lose its clear effect. The discoloration will also happen if you pigment your epoxy, although it will be less noticeable with a darker pigmentation. Unfortunately, there is not yet a protective coating in the market to completely prevent this yellowing effect. 

Extreme Temperature Fluctuations: 
Wood and epoxies expand at different rates. After fully curing, EcoPoxy resin on its own should not shrink or expand with subtle temperature changes, however, with extreme temperature fluctuations there is a risk of separations or cracks where the wood and epoxy meet. This could happen with any other substrates that change size due to temperature change.

Recommendations:
If you live in a place where the temperature drastically changes, we do not recommend keeping any epoxy project outside; instead, keep it indoors at average room temperature.

If you are going to try an outdoor piece, we suggest using a UV-resistant finish or coating for additional protection i.e., any UV stable polyurethane or finishing oil.

Remember to follow the EcoPoxy instructions about the mixing ratio for your specific product. Failure to follow the mixing ratio could result in premature discoloration of your project.