- The Heavy Press Program (1950s–60s) is highlighted as a historical example of massive state investment in forging presses capable of shaping large aerospace and automotive components, illustrating how public–private megaprojects can create long-term industrial capacity.  
- A Medium article on “manufacturing next-generation electronics like T-shirts” is shared, describing roll-to-roll printed electronics using copper-based conductive inks; participants note the marketing claim that subtractive PCB processes are “unsustainable” is undercut by the ink’s need for several-fold more material to match copper conductivity.  
- Practical PCB prototyping trade-offs are debated: photoresist methods give finer resolution but still require CNC milling for multilayer or complex boards, whereas direct CNC milling of copper-clad boards avoids chemicals and is faster for simple prototypes.  
- Copprint’s conductive copper ink (≈ €550 kg⁻¹) is judged too expensive for casual experimentation; participants would prefer small-volume samples and question the economics versus traditional copper foil.  
- A 2021 meta-analysis on childhood lead exposure and crime is dissected in detail; participants criticize the paper’s statistical opacity, its focus on legal outcomes rather than direct violence metrics, and the graphical practice of not zeroing the y-axis.  
- The largest single study in the meta-analysis (Grönqvist et al., 800 k Swedish children) is shown to have near-zero effect in the aggregate plot, yet its own abstract claims significant impacts; discussion reveals Sweden’s average blood-lead (~6 µg dL⁻¹) sat just below the 7 µg dL⁻¹ threshold the study identifies for crime, explaining the apparent contradiction.  
- Evidence is compiled that the lead-crime relationship is non-linear: U.S. averages fell from 14 µg dL⁻¹ in 1979 to 3 µg dL⁻¹ in 2018, with most older studies clustering around 10–20 µg dL⁻¹, suggesting meta-analyses that pool low- and high-exposure cohorts with linear models may misestimate effect sizes.