Obtaining higher operating temperatures, greater energy production, and inherent stability in microreactor technology requires new geometries (such as to the core and coolant channels) and materials compared to light water reactors. These novel geometries and materials present fabrication and joining challenges that are currently limiting structural material options for microreactor use. In this work, several manufacturing, welding, and joining techniques were evaluated to manufacture a coreblock for a microreactor. This was accomplished through studies of a prototype non-nuclear heat pipe test article with salient design features, including full-length heat pipes of ~0.3 m in length with tight tolerances in multiple directions. Specifically, traditional subtractive machining of wrought parts, additive manufacturing, and unique subtractive machining (i.e., gundrilling) were investigated as means of fabricating challenging geometries using Type 316L Stainless Steel. Machining and AM were limited to parts less than 12 in (0.30 m) in height, but preliminary, small-scale results indicate that gundrilling may be able to produce parts up to 31 in (0.79 m). Once fabricated, a process to utilize electron beam welding through multiple layers of materials with gaps in between (tier welding) was investigated to create the full-length structure. Tier welding was successful on sub-size parts, but results showed that tier welding was not feasible for full sized parts due to the thickness and challenging geometries, which required a penetration depth of 4 inches and involved several joints at once with heat pipes separating the joints. Brazing or diffusion bonding processes may provide a path to joining parts, but experimental results on full-scale parts are required to support this assessment. In total, while these results indicate that issues still exist for manufacturing microreactor structures, this work improved the understanding of these challenges and investigated several solutions.