if your mold and injector are from bear you should have no problem. plastic left on the tip of the injector from filling it will seal the mold. Dont force it, just use little pressure and wear gloves. Nothing is needed on the mold to prevent sticking. Just coat the orings every so often with oil and you will be fine. I have thousands of injections on bears injector and have had no problems at all. When heating there will be fumes, less if you use the microwave. work in a ventilated area. IF your plastic gets to hot it will burn and put off toxic gas. Dont breath it in.