Had a similar experience when we were renovating our kitchen and decided to custom-make some decorative fixtures using injection molding. Thought we'd be eco-friendly and use recycled plastics—big mistake. One batch was smooth sailing, the next was a total disaster. I remember one particularly frustrating weekend spent prying brittle, warped pieces out of molds, wondering why I didn't just buy something off the shelf.
Eventually, we switched to bio-based plastics too. Definitely pricier, but at least the results were consistent enough to justify the cost. Still, if you're just doing a small run or something decorative, casting might save you some headaches. Injection molding is great for mass production, but unless you're ready to spend time (and money) dialing in your setup, it can be more trouble than it's worth.
