Solving Epoxy Hardening Problems – 3 Tips for a Stronger Bond

Sometimes, even with enough time, epoxy resins refuse to harden. When this happens, the obvious question is epoxy not hardening what to do? To ascertain what went wrong and why the epoxy isn’t hardened, you need to know how epoxy works. Here are some reasons why epoxy isn’t hardened.

Why is epoxy not hardened?

Here are some reasons why your epoxy doesn’t harden:

Solving Epoxy Hardening Problems - 3 Tips for a Stronger Bond || Why is epoxy not hardened?

Low Ambient Temperature

The room temperature of where the epoxy is installed should be around 23-30 degrees. This is to make the product harden quickly. However, when the ambient temperature of the room is low, the epoxy mixture will be sticky.

Wrong ratio

Another reason why an epoxy isn’t hardened is because of an incorrect ratio. The ratio between raisins differs from one brand to another. If you can’t maintain an ideal ratio of two elements it affects the hardening process. Follow the right specifications as directed on the product.

Bad mixing process

If you don’t mix the epoxy solution properly, then bonding will be difficult. While many viscosity liquids easily diffuse through one another, this doesn’t apply to epoxy. At least 4 minutes is required to get the mixing process right.

Bad measurements

If you don’t get the measurement of resin harder right, this could make the hardening process difficult. Ensure you measure epoxy resin on volume, rather than weight.

What to do when an epoxy doesn’t harden?

While you should ensure your epoxy should be mixed properly when it doesn’t harden even after your efforts, this is due to these reasons :

Solving Epoxy Hardening Problems – 3 Tips For A Stronger Bond || What to do when an epoxy doesn’t harden?

Sticky resins

When your epoxy doesn’t garden because of sticky resins, you should dry it for more than 24 hours. Sticky resin problems happen when your microstructure isn’t solidified. When you dry them properly in the sun or somewhere with enough air, it should be resolved. However, if this persists, sanding will work.

Soft spots

Another problem that can cause epoxy not to harden is soft spots. These are random spots of unsolidified resins. This happens when there is a wrong portion mixture. To solve this problem, you should sand off all solidified spots on the surface. After sanding, you should whip them clean using a clean material.

Runny Resin

This is a common cause of why epoxy doesn’t harden. When you notice wet resin spread over the surface without a portion, this is the cause. To fix this, you should scrap all materials off the surface, if possible. You don’t need any sanding if the whole resin surface has been unmodified.

Will an epoxy harden if I use too little hardener?

Yes, one of the problems of epoxy not hardening is when there is little hardening. The right ratio is 1:1 for a resin to a hardener. When this isn’t followed and there is a ratio tilt, malfunctions could happen.

What can cause an epoxy resin to be sticky?

Even after leaving for more than 20 hours and your epoxy resin surface is still sticky, the temperature is the culprit. Ensure you check the room temperature and ensure it isn’t too low. Also, try to lengthen the curing period because resins differ from one another.


To the epoxy not hardening what to do question, the article has provided an in-depth explanation of the possible problems and solutions. If after trying the following solutions without good results, you might want to talk to a professional.

Nick Shushan
Nick Shushan

Epoxy Expert and the CEO of NYC Epoxy Flooring. I love epoxy so much and spend my entire day speaking about epoxy and working on epoxy projects.

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