While the head and hands will be vinyl - you have a choice of two different types of body - one is referred to as Cortex and the other as Vinyl. Both body types are pre-built.How to fix loose heads
If you regularly remove your Smart Doll’s head—whether to change clothes or to “neutralize” them at night (because a headless Smart Doll can’t run around the kitchen)—you may notice over time that the head becomes loose, pops off with a slight tug, or worse… enters SHD (Spinning Head of Doom) mode.
If this happens, here’s what to do:
1. Heat and Shrink the Neck Hole
- Remove the head, wig, and headcap.
- Place the head upside down on a flat surface.
- Use a hairdryer to gently heat the neck hole area until the base of the head feels warm to the touch.
- As it cools, the vinyl’s plastic memory should cause the hole to shrink back closer to its original shape.
Important: Let the head cool completely before reattaching it.
2. Check the Fit
Sometimes, the issue isn’t an enlarged neck hole—it’s simply that the head isn’t seated properly. When reattaching, press down firmly and ensure there’s no gap between the base of the head and the top of the neck.
With these steps, you should be able to resolve the Spinning Head of Doom.
Why Heat Fixes a Loose Neck Hole
Smart Doll heads are made from sofubi—a type of soft vinyl (PVC) that’s classified as a thermoplastic. Thermoplastics soften when heated and harden when cooled, making it possible to reshape them gently without damage.
During molding, the vinyl forms a specific shape. This shape gets “locked in” at the molecular level when it cools. If the neck hole becomes stretched from repeated removal, reheating with a hairdryer temporarily softens the vinyl, letting it shrink back closer to its original form—a behavior often referred to as “plastic memory.”
Safe range: Vinyl begins to soften around 60–80°C (140–176°F). A regular hairdryer provides just enough heat to encourage this realignment—without risking warping or burns (as long as you don’t overdo it).
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