Sublimation tumblers are coated with a special polymer layer that allows them to accept dye sublimation ink. This process involves heating the ink until it turns into a gas and bonds with the polymer coating, embedding the design into the surface of the tumbler for a durable and high-quality finish. This coating is crucial as it ensures that the print does not wear off, fade, or peel easily, maintaining the integrity of the design for a long time. The polymer coating is specifically designed to withstand high temperatures and chemical reactions involved in the sublimation process, making it an essential component of sublimation tumblers.

To exclude files generated by Yarn from version control using Git, you need to utilize `.gitignore`. This file instructs Git to ignore specific files or directories. For Yarn, typically you want to ignore the `node_modules` directory where all your package dependencies are installed. Start by creating a `.gitignore` file at the root of your project if it doesn't exist. Add `node_modules/` on a new line. Optionally, you can include other Yarn-related files like `yarn.lock`, but this is not recommended as `yarn.lock` ensures consistent installs across different machines. If you still wish to ignore `yarn.lock`, add it on a separate line. Ensure your `.gitignore` file looks similar to: ``` # .gitignore node_modules/ # yarn.lock ``` After updating the `.gitignore` file, stage and commit your changes with commands like `git add .gitignore` and `git commit -m "Updated .gitignore to exclude node_modules"`. This setup keeps your repository clean and manageable, reducing the size and improving clone times.

If your resin hasn't hardened, it might be due to incorrect mixing proportions, low temperatures, or expired materials. First, ensure you've measured and mixed the resin and hardener correctly, typically in a 1:1 ratio, but check your product's instructions as this can vary. Mixing thoroughly is also crucial to initiate the chemical reaction needed for curing. If the ambient temperature is too low, try moving your project to a warmer spot since most resins cure best between 75°F and 85°F (24°C and 29°C). If you've confirmed these factors aren't at fault, your resin or hardener might be too old. Resin components can degrade over time, losing their effectiveness. If this is the case, purchasing new resin is often the only solution.