I built a Dual OptiPlex Homelab in a 3D-printed shell. This is a practical how-to for printing the case on a Bambu P1S, then wiring and configuring the two OptiPlex units. I give parts, print tips, cable management tactics, cooling fixes and simple automation ideas. Read it and use what fits your kit.
Start with the print. I printed the main case in PETG-GF for strength and surface finish. The Bambu P1S handled the geometry cleanly. Expect the main shell to take around 15 hours on a single 0.4 mm nozzle. Print orientation matters. Lay broad, flat faces on the bed to cut support time. Add heat‑insert holes where the OptiPlex mounts meet the shell. Use fuzzy skin or a similar surface option for the visible faces; it masks layer lines. Keep wall thickness and infill up for load points, 20–30% infill is a good balance. Use a brim or raft for the large, thin sections to avoid warping. Fit test the boards and connectors before final cleaning. Glue small brackets with hot glue during assembly; hot glue is quick and forgiving when the space for cable management is tight. Pack any fragile connectors with foam or PTFE tape where they might rub the plastic. If you plan on reusing the OptiPlex front panel, remove the top cover during disassembly and keep the original fastenings for a cleaner finish.
On power and cabling, plan like you mean it. I used a single external 19.5 V 240 W laptop-style supply to feed both machines with local buck converters per unit. That keeps the external cable count low and lets the buck converters supply the correct rail voltages to each OptiPlex board. Label every cable. Use short DC pigtails and heatshrunk joins for tidy runs. For ethernet, terminate short internal leads to Keystone RJ45 couplers mounted at the case rear, then run a single patch cable to your switch. Keep the power distribution on one side and the network on the other to reduce crossover. Route cables through defined channels and secure them with low-profile cable clips or zip ties. Avoid looping mains cables near sensitive SATA or front-panel headers. A small Arduino or microcontroller works well for basic automation. Mine sits on a simple PCB and controls a 5 V Noctua 92 mm fan via a MOSFET, plus it monitors a buck converter’s output with a voltage divider to guard against undervoltage. If you add automation, use isolated sensing and a logic-level MOSFET to switch fans or relays. Use heat inserts at PCB mount points and secure small headers with M2 screws.
Cooling matters more than most people expect. The dual layout compresses airflow. Make a clear intake and exhaust path. I used a single 92 mm 5 V Noctua to pull air out the back. Place the fan downstream of both CPUs so it draws through the main vents. Keep the PSU and buck converters in a partitioned area with small vents. Add thermal pads on any board or power part that sits close to the plastic wall. Check fan orientation twice before final assembly. For temperature monitoring, run lm-sensors or the vendor utilities from each OptiPlex. Do not rely on a single sensor reading near the fan; monitor CPU and VRM temperatures separately. If temperatures are high, add a small duct or a secondary low-speed fan to force air over the VRMs. Quiet fans with higher static pressure work best in tight ducts, while high‑CFM fans suit open flow.
Testing and configuration take time. First test for shorts and correct voltages at the buck converter outputs with a multimeter before connecting any motherboard. Power each OptiPlex one at a time, confirm POST and BIOS settings for boot order and wake-on-LAN. For networking, assign fixed IP addresses or DHCP reservations so your automation scripts find each machine reliably. For automation, I scripted a small SSH-based controller to issue graceful shutdowns, reboots and updates. Where remote power cycling is required, use a relay triggered by the Arduino or a smart PDU in-line with the main supply. For troubleshooting, follow a simple checklist: verify the external supply voltage, check buck converter outputs under load, confirm fan spin and direction, and run a 30-minute stress test on each CPU to catch throttling. Record voltages and temperatures during the test. Keep a bag of spares nearby: extra DC plugs, short ribbon cables, zip ties and a tube of silicone or hot glue. In my build the printed case improved airflow over the stock layout once ducts and exhaust were in place. The tight cable management pays off. You will trade some build time for a quieter, neater homelab and simpler long-term management.
