- Dan Berard’s home-built scanning-tunneling microscope (STM) was highlighted as a low-barrier entry point to ultra-high-precision metrology.  
- Participants framed self-replicating hardware as a “combinatorial diamond” rather than an exploding pyramid: the goal is to collapse dependencies by maximizing the multipurpose utility of each component while minimizing the number of distinct feedstocks and processes.  
- Piezoceramics (especially PZT) were singled out as a near-ideal “sweet-spot” material—simple to form by ceramic techniques, capable of sub-micron motion without gears, and already demonstrated in inchworm, traveling-wave, and membrane micropump actuators.  
- Alternative actuator concepts discussed included: PCB-printed motor coils, voice-coil drives, flexure-based amplification, muscle-wire (nitinol) thermal actuators, air-bearing spindles, and speculative “piezohydraulic” fluids that would expand under electric fields.  
- Clay was proposed as a universal feedstock for an early-stage clanking replicator because it is abundant (terrestrial and lunar regolith), moldable as an aqueous slurry, and refractory once fired; open questions remain about variability in mineral composition and the difficulty of machining or actuating fired clay parts.  
- A three-track development plan was sketched for a well-funded effort: (1) clay-based 3-D printing & machining, (2) low-tech solution chemistry and electroplating lab, and (3) vacuum-process module (lasers, ion-beam/CVD) for higher-precision or thin-film work; each track would iteratively supply parts to the others while the overall “diamond” is progressively miniaturized.  
- Ion-beam and electron-beam fabrication were identified as the most powerful—but presently inaccessible—tools for open-source self-replication; the “Metalicarap” concept of massively-parallel ion-beam welders was cited as a 50-year-old industrial technique still lacking an open 3-D printer implementation.  
- Organic chemistry routes were cautioned against because of political optics (“flesh-eating robots”), limited off-world feedstocks, and perverse economic incentives; inorganic pathways (aluminum, iron, silicon, ceramics) were preferred.  
- Practical near-term hacks mentioned: CVD or thermal oxidation of silicon onto clay or printed-plastic labware to create glass-like vessels without a full glassworks, and using differential thermal expansion of carbon-fiber-backed PCBs for metrology instead of traditional metals.