Thoughts on scaling up a large print build on the P1S

My experience with those enormous builds shows that the biggest variable isn't necessarily the material, even if it's PETG, but the cooling setup. When I tried printing a massive architectural model of a city block last winter, I had to switch from the standard setting to a 'high flow' profile because the sheer thermal mass of the part was slowing down the layer adhesion. The cooling fan on the P1S actually struggled to maintain consistent airflow across such a wide surface area, especally in the first few layers. I found that the secret to keeping the quality up on those big jobs wasn't necessarily using more glue between segments, but rather optimizing the flow rate. Running things at 0.1 mm layer height and just letting the printer work through the initial slow layers kept the geometry cleaner, but it definitely increased the overall print time. For a part that big, I was prepared for the 40-hour runtime. I ended up running the build over three nights to prevent any thermal drift in the enclosure. It felt like a chore, but the final finish was much better than if I had tried to rush it. It's just a matter of matching the slicing parameters to the size of the physical object, not just pushing the machine to its limit.

I actually think focusing on the cooling setup for a massive print might be misdirect. While thermal mass is certainly a factor, I’ve found that the bigger hurdle for parts that large isn't necessarily the flow rate or how hot the nozzle runs. When I scaled up a giant industrial bracket from STL files, the failure points weren't melting; they were layer shifts and poor adhesion between sections when the print reached critical size.

My approach for very big parts is totally diffrent. Instead of fighting the temperature, I adjust the print speed drastically, usually dropping it by 30% to ensure every single layer bonds perfectly before the next one starts. It takes way more time, but it completly changes the structural outcome. For example, on a recent large tool housing I made, reducing the speed from the stock 250 mm per second to maybe 150 mm per second prevented all the subtle warping I was worried about. I also always orient the part so that the biggest surface area is hitting the bed. If you have a tall structure like the statue mentioned, printing it standing up on its narrowest base forces the shear forces to travel vertically, which is a structural nightmare. Laying it flat, even if it makes the overall footprint huge, allows the layer lines to handle the load better. It’s about managing the physics of the material, not just tuning the printer’s internal fans.

I'm still pretty new to all this so take my take with a grain of salt, but the filament usage question is the part that scares me most. I did a life size helmet on my little printer and it ate like half a spool just on supports I threw away. Does anyone actually calculate the material needed before slicing something this big, or do you just stock up and hope? Also curious if you sand the seam lines between segments first or fill them with something after assembly, since I just glued mine and the gaps still bug me.

For me the material choice mattered more than I expected. I did a big dragon bust in PETG and the wide flat sections warped like crazy on the bed, had to scrap two sections. Switched the whole thing to PLA and it just went togather clean, way less sanding too since the layers laid down flatter. PETG gets shiny and stringy on big surfaces which is a pain to finish. On the filament usage question, I just weigh the spool on my kitchen scale before and after each section, gives you a pretty good idea of what you've burned through.