How We Sort Parts for our LEGO® MOC Kits

Have you ever wondered how our custom LEGO® MOC Kits are prepared before they reach your doorstep? When you open an official LEGO® set, you’ll often find the parts neatly machine-packed into numbered paper or plastic bags. It looks simple on the surface, but behind that tidy presentation is a surprisingly detailed and time-consuming process. In our case, the process is even more complicated, with no machines involved!

Every Bobby Brix MOC Kit is sorted and packed by hand!

From sourcing the parts to inventory checks and final packaging, each step is done with care to make sure you receive a complete and enjoyable building experience.

Parts Sourcing

Once a LEGO® MOC design is finalized, the next step is sourcing the exact parts needed to turn the digital model into a physical build. This step comes with its own challenges.

LEGO® regularly retires parts and colors, just like they retire full sets. When a part goes out of production, it can significantly increase the cost of a MOC kit or force a design change late in development. In some cases, we even have to revisit a finished model and adjust specific elements to keep the kit viable.

All genuine LEGO® parts used in our kits are sourced directly from LEGO® through their official Pick a Brick service. Using CSV part lists, we can upload everything we need in one go and let the system match parts based on availability.

That system isn’t perfect. Some parts may show as “out of stock” even when suitable alternatives exist under different part numbers. Ideally, LEGO® should allow automatic substitutions in the future, something we hope to see improved over time.

If you’d like to learn how to use LEGO® Pick a Brick yourself, we’ve written a step-by-step guide here ➡ How to Buy LEGO Parts Using XML or CSV Files

Even with these limitations, Pick a Brick has dramatically reduced sourcing time since its CSV upload feature was introduced in early 2025. Before that, parts had to be added manually or sourced through marketplaces like BrickLink or BrickOwl, which often resulted in much higher costs.

Once the order is placed, parts usually arrive within one to two weeks, depending on the season and order size. And when parts arrive, we can sometimes expect big bags of 2-3 kilograms of only LEGO®!

Fun fact: For the upcoming LEGO® Michalská Brána MOC Kit, the 1×1 half-circle tiles in Sand Green were phased out by the end of 2025. We secured a batch to future-proof the set, but a design revision may be required later on.

Sorting & Inventory Process

All sorting is done in a ventilated workspace while wearing gloves. We use soft textile gloves instead of latex ones to avoid fingerprints and prevent bricks from sticking to the material during handling.

For sorting, we rely on our own 3D-printed sorting trays, designed specifically for LEGO® parts and available in our store ➡ 3D Printed Organizers Collection

Depending on the size and complexity of a MOC kit, we use one of two methods:

• Set-by-set sorting, where all parts for one kit are sorted and verified before moving on
• A hybrid system, where larger parts are sorted first across multiple kits, followed by detailed sorting of smaller elements

This approach allows us to verify inventory more accurately, especially for larger or more expensive parts. Once a kit is complete, the tray is closed and moved on for packaging — or stored temporarily if additional steps are needed.

What happens if a set is incomplete?

If a part is missing or damaged during sorting, we first check our spare parts inventory. If the part isn’t available, we wait for the next batch of parts to arrive. In cases where LEGO® significantly under-delivers compared to what was ordered, we contact LEGO® customer support directly to resolve the issue.

And for customers: if a MOC kit ever arrives with a missing part, we ship replacements free of charge. No hassle, no extra cost!

Packaging

Seeing a MOC kit fully packed is one of the most satisfying moments of the entire process. After hours of sourcing and sorting, the model finally comes together as a finished product.

Each kit is packed by hand into paper bags, sealed with paper labels. The number of bags depends on the model size, box dimensions, and the type of parts inside.

For example, the LEGO® Bratislava Brickcard MOC Kit uses multiple baseplates for its structure. To prevent scratches, smooth tiles and plates are packed separately. A third bag typically contains smaller elements like clips, tiles, and detail pieces that can safely be grouped together.

Ready for Sale

Once the parts are sorted, packed, and labeled, the MOC kits are stored safely and ready for purchase! Every kit that leaves our workspace reflects the same goal: accuracy, transparency, and care; from the first brick to the last!

Since January 2026, selected MOC kits can be ordered with or without printed instructions. Choosing the digital-only option comes with a small discount and still provides full access to the PDF instructions. If you select printed instructions, digital access is included as well.