Epoxy is one of the best glues for hobbyists and industrial uses that we currently have. And epoxy resin is a fantastic material for any kind of woodworking, jewelry, and art projects. But while epoxy resin sticks to a lot of different materials there are also a few materials that it will not stick to. So what does epoxy resin not stick to?
Epoxy resin does not stick to silicone, parchment paper, painters tape, rubber, hot glue, and most plastics like polyethylene plastics, polypropylene plastics, vinyl, PTFE, polystyrene, PVA, acrylic plastic, PVC, polycarbonate (Tupperware), and ABS.
Epoxy resin adheres to materials that have a higher surface energy than itself. Most epoxy resins have a surface energy of around 45 Dyne/cm.
ABS, PVC, and acrylic plastics are closest to the surface energy of epoxy resin which is why all of these materials will adhere a little bit to the resin but they can usually be separated from the cured resin with a little force.
Materials that Epoxy Resin Does Not Stick to
Here is a full list of materials that epoxy resin does not stick to:
- Parchment paper
- Painters tape
- Polyethylene (Hot glue)
- Acrylic (plexiglass)
- Polycarbonate (Tupperware and most plastic containers)
So, as you can see, epoxy resin generally has a hard time adhering to most kinds of plastics.
Which makes plastic a good material to cast epoxy resin in. I personally use acrylic sheets a lot for casting resin. You can see examples of that in my guide on how to make fake water for a diorama right here.
From all of the materials listed above silicone is the one material that epoxy resin simply won´t stick to at all no matter what. Because nothing sticks to silicone but silicone.
This makes silicone a perfect choice for making molds out of for pouring epoxy resin. You can learn more about that in my guide where I teach you how to make your own silicone molds.
Why Does Epoxy Resin Adhere to Materials?
Epoxy resin is a very interesting kind of material that does not only adhere to materials through a mechanical bond but instead on a molecular level by reacting with the surface of the solid material.
Epoxy resin adheres by reacting with the reactive parts of the material that it gets into contact with.
The reactiveness of a material is measured by its surface energy. This basically means how many reactive atoms there are present on the surface of a solid material.
It is measured in Dyne/cm and every materials with a surface energy of more than 45 Dyne/cm will adhere to resin.
Everything below 45 Dyne/cm will either not adhere at all to the resin or only stick very little to it.