Epoxy is an extremely strong adhesive, which is why it’s favorable. As long as no mistakes are made during the coating process, that is. But as we all know, mistakes can and do happen. Epoxy can end up where it doesn’t belong. Removing cured epoxy from a substrate can be very tricky. However, it’s not impossible.
When it comes to removing cured epoxy from substrates, there are essentially three options:
Heating the epoxy
Epoxy starts as a liquid and becomes a hardened solid as it heats up when it is mixed. To remove epoxy, it can be heated to get it back to its liquid, or softened, state. From the liquid state, the epoxy can be scraped from the surface. When epoxies are heated to high temperatures they will smoke and give off odors which is why a face mask and proper ventilation is necessary during the epoxy removal process. Epoxies can also become softened and removed when they are exposed to boiling water.
Freezing the epoxy
Use a refrigerant spray on the epoxy to freeze it. The epoxy will become brittle and should break off easily as you chip away at it.
Using chemicals
Soaking the cured epoxy in certain chemicals has shown to be effective in removing it from the substrate. Methylene Chloride has shown to be the most successful, but it is hard to obtain because it is a carcinogen. Other chemicals that can be used include toluene, NMP (n- methlypyrollidone), MEK (methyl-ethylketone), and sulfuric acid. When using chemicals, be sure to take precautions to prevent contact with skin and do not inhale chemical vapors.
While these methods are successful in removing epoxies, they may damage the substrate surface during the removal process. The parts likely won’t be re-usable. Depending on the project and product, if the product is usable with unwanted cured epoxy, it might not make sense to remove it.