A broken Prusa i3 with a blown-out hot-end became the basis for an embedded 3D printing rig. Riley replaced the hot-end with an open-source Allstruder syringe pump and a Caribou Duet 3 motherboard, then used the rebuilt machine to extrude liquids directly into a supportive medium, specifically hair gel, rather than open air. The technique, called E3DP, makes it possible to print materials like silicone, epoxy, and biological tissue that collapse without structural support during deposition.
The build works, with conditions. Cream cheese validated the setup. Two-part epoxy failed because hair gel chemically rejects it, and a 40-minute cure window left no margin for error. Sylgard 184 silicone produced a recognizable trifold torus shape, but hair gel contains additives that inhibit silicone curing, leaving the print still uncured after several days. The underlying problem, that supportive media and print materials interact in unpredictable ways, is an active research problem: a 2026 paper by Min Ye et al. in the International Journal of Extreme Manufacturing describes a self-healing support medium called EPICS specifically to address tissue printing failures, and a 2025 paper by Hejoon Jun et al. in Applied Materials and Interfaces documents why Newtonian fluids like silicone oil are especially unreliable to print.
The full video covers the hardware build and the chemistry failures in enough detail to replicate or avoid the same mistakes. A 2026 review by Rongji Tang et al. in Frontiers in Materials maps the broader E3DP field, including support material reuse and extrusion control, applications ranging from soft robotics to microfluidics. The gap between lab-grade E3DP and a hacked Prusa doing it on a workbench is closing. Read the original to see exactly how close, and how much the support medium choice still matters.
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