What does hot glue not stick to?

Hot glue, also known as hot melt adhesive, does not adhere well to certain surfaces. Here are some materials that hot glue typically does not stick to effectively:

1. Greasy or Oily Surfaces: Any surface that has oil, grease, or lubricants will repel hot glue, preventing proper adhesion.

2. Silicone: Both silicone rubber and silicone coatings are highly resistant to hot glue. The non-stick properties of silicone make it difficult for the adhesive to bond.

3. Teflon (PTFE): Teflon-coated surfaces are known for their non-stick properties, which hot glue cannot adhere to.

4. Wax: Wax-coated surfaces or items made of wax will repel hot glue.

5. Parchment Paper: Often used as a non-stick surface in crafting and baking, parchment paper does not hold hot glue.

6. Greasy or Powdery Surfaces: Any surface that is greasy, oily, or covered in powder will not allow hot glue to form a strong bond.

7. Wet Surfaces: Moisture can interfere with the bonding process of hot glue, making it less effective on wet surfaces.

8. Smooth, Non-Porous Surfaces: Some very smooth and non-porous surfaces, such as some metals, ceramics, and plastics, may not allow hot glue to adhere strongly. However, this can vary depending on the specific type of plastic or metal.

9. Polyethylene (PE) and Polypropylene (PP): These types of plastics have low surface energy, making it difficult for hot glue to stick to them.

For best results, hot glue should be used on clean, dry, and slightly porous or rough surfaces to ensure good adhesion.