I happened upon an old stack of slides, probably from the Mid-199's I suspect, that recorded the step-by-step transformation of a Breyer Stock Horse Mare into a Standing Stock Horse. This is pure Old School; before heat guns, before Apoxie Sculpt, before Mohair and before I had an airbrush! But the basics still hold true. Enjoy!
Boil!
Back then I used hot water to soften the plastic for bending. This often discolored the plastic, softened more than the intended joint, and more than one second-degree burn from splashing myself. Thank goodness they invented heat guns!