• minute Read
  • March 31, 2021
  • Massive Guide To Building Custom Lego Sets

    Building custom Lego sets is one of the most fun things you can do with your bricks. It allows you to go beyond the sets you have purchased and make some really amazing inventions. We have all seen pictures of a custom Lego build and thought, "I want to make that", well now is your chance. 

    I am going to teach you everything I know about building custom Lego sets. I will show you how to plan the build, get the bricks and avoid some costly mistakes. 1st thing...If you plan to build custom Lego sets then you need to start by organizing your bricks. If your bricks are already in order then skip ahead, but for everyone else this is very important. 

    I have created detailed guides that show you the fastest Lego sorter, the best ways to organize your Lego and some great and inexpensive Lego storage. I also have the whole thing put together in a program called SOS Bricks. This gives you my exact system for sorting, organizing and storing Lego. It also shows you how to build more for less $$$ using this system. Please, do yourself a favor, organize your bricks. 

    Lego Organizing Tip

    You don't need to separate every single brick. In fact many should stay together. Even if you are washing and cleaning some used bricks you just bought, you should keep some bricks together. Minifigures, Tires/Rims, and Hinge or Swivel Bricks should all remain together. Discover more in our FREE Lego Sorting Guide

    3 Different Types Of Custom Lego Sets

    When it comes to custom Lego sets there are 3 main types. Which one you decide to build will depend on a few factors. 

    First is your skill level. If you are used to building only from instructions, then starting with a 5,000 piece original creation is not your best plan. You may want to start with some smaller builds, or work on it in parts. We will talk about planning these builds soon. 

    Second is your collection. If you have 500,000 organized bricks in your building room, the options are wide open. If you have 2,000 bricks in a bin in your closet, we have some limitations. This isn't to say you can't or won't add bricks for this build. In fact I'm going to explain some great ways soon, but this can get expensive. 

    Third is your budget. Do you have a budget? Well you should. Otherwise it is easy to spend $100's of dollars on special bricks. Often this is more than you would have paid for this build to begin with. Do yourself a favor, make a budget for the project and plan the build before you start buying. 

    Last is your building space. This factors into both the size and length of time to build. If you want to build a Lego city you need a lot of space. If you want to build a modular starship it may take a few weeks. Make sure you have somewhere safe to keep your builds as you work. My 2 kids get into and play with everything. So I don't build anything I can't finish in one night. Each space is different, just think it through. 

    Custom Lego Set Instructions


    Instructions for custom Lego sets are available to build almost anything you can imagine. These can range from a micro-builds with 30-40 bricks up to massive ships with over 1/4 of a million bricks. Commonly referred to as MOCs (My Own Creations) these take every shape and form.

    If you want to build a classic truck, there is a MOC for that. A set from your favorite movie... yup probably too. This is just a small snippet of the tens of thousands of MOCs available on Rebrickable. The site focuses on custom builds and rebuilds from mixing sets. Instructions are for sale and vary from $5-20 depending on the size of the build and how famous the designer is. You can look at the parts lists before buying instructions, which is really helpful when planning. Instructions are either a follow along video or pdf download. 

    Bricklink also offers MOCs for sale, but most of these come with the bricks. These MOCs are far more expensive with many in the $200+ for sets with over 1000 bricks. This is a great way to get the exact set you want, but it is expensive. Many of these ship from overseas so this can add to the cost. Plus, you probably own half the bricks needed, I'll show you how to make this work for you soon. 

    Modified Lego Sets

    Modifying a Lego set is the easiest and least expensive way to come up with something new. You can start with any of the 1,000s of free instructions available online and make it your own. This is usually one of the steps that builders take as they move from building with instructions to creating custom Lego sets. 

    Both Lego.com and BrickInstructions.com have instructions for almost every official Lego set made. They are well organized and the PDFs are good enough to build from. (kinda low quality images, but still very workable) Look for similar shapes and styles to what you are building. 


    If you want to build your favorite spaceship, look at some ships in the Star Wars, Space Police and Creator lines. See how they build the frame and think about the design. Try to find one that is similar enough and use it as a guide. You can also use sections from other builds (a wing or rocket) that have the right style. 

    If you find a set that is very similar (style and colors) to what you want to make, it is probably worth buying that set. This will give you a good base of bricks to work with. If you find yourself missing a few bricks you really need, don't fear. I will explain the best ways to work around this soon. 

    Create Your Own Custom Lego Set

    Creating your own custom Lego sets is the pinnacle of building for many Lego builders. I don't mean just throwing together some parts that look cool. I am talking about builds that rival the official ones from Lego both in design and style. These are the creations of Lego Master Builders and can take months, even years to perfect. They may require adding a Lego wall for vertical building or a Lego Table if you are building a city.

    These builds take focus, planning and a whole lot of bricks. There isn't enough time to include much about creating your own custom Lego set in this article. I will be adding a lot about this in the coming months. For now I will keep it simple and direct you to a great video.


    JC from Small Brick City has quite a few on designing Lego MOCs. His 5 step process is easy to follow and works quite well. 

    1. 1
      Create a detailed concept (size, colors, design) so that you know exactly what you are trying to build.
    2. 2
      Find photos or illustrations of what you are trying to build or things that have similar style. Decide exactly how it will look.
    3. 3
      Pick a feature element to start with. This is something unique and a place to start building.
    4. 4
      Build, re-build, and build again. Keep trying different techniques to improve the design.
    5. 5
      Add details to make it great. These can be landscaping, texture, anything to make it more rich and detailed.
    We Love Used Bricks!

    Our family has had some amazing success buying entire used collections. These usually come from teenagers who have chosen to move on from building. The last 2 purchases have added over 25,000 bricks for $175 (95% off retail prices). Check out our Sorted By Sunday system for more details on this. 

    Getting The Bricks To Build Your Custom Lego Sets

    Building a custom Lego set can be 2 very different steps. Designing the build or finding instructions is where you determine what bricks need to go together and how. Getting those bricks can be a totally different process. If you already have your collection stored in a Lego organizer this will be fairly simple. You have plenty of bricks to work with and they are easy to find. If not... let's get to work.

    Create Your Own Custom Lego Set

    The easiest place to start is with the bricks you already own. If you are building something from instructions , you should have a list of parts needed. If you are creating your own design it will be a little more difficult, but you should still have a pretty good idea what you need. (you can design it digitally to make get an exact part list) In either case it is time to find out which bricks you have and what you need. 


    Before I begin working on custom Lego sets I like to take apart my old builds and make sure everything is put away. Look for any old models you may not want to keep around. This is also the time to add some bulk bricks if you can find them cheap. (more on how to do this in a moment) 

    Once I have them organized I like to print my parts list out. Because of my storage system (Sorted By Sunday) I cut apart the build list and organize it by category. Then I work my way through the parts list pulling out every piece I have. I also pull out any substitutes that may work (similar colors or shapes) and set these aside. 

    At the end of this I have a list of bricks that I need and ones that would be nice. You will be amazed how much of a build you already own or can work around.  I am going to give you a detailed example to show this.

    Example: Lego City Fire Truck 60002

    I picked a simple Lego build from 2012 to help you see that you don't need to buy lots more bricks in order to make custom Lego builds. It is the Lego City Fire Truck 6002. I am going to post the parts list below for you to see. This is a 208 piece retired set that costs $30-50 on Ebay. Let's look at the parts.

    I circled the parts that are in almost every Lego collection in green. These are really, really common pieces and if you have more than 5,000 bricks (1 medium bin) you almost certainly own them. The pieces in yellow are a little more rare. All of them were in our collection (Approx. 30K bricks) although a few were not the exact color.


    Lastly are the red bricks, these are rare and unique. Lego tries to include some of them in each set. To finish our build we have to decide: either change something to make it fit the bricks we have, or order the bricks we need and finish it exactly. (strategies on this in just a moment) 


    Buy Lego Bricks In Bulk - Cheap

    Buying Lego in bulk is one of my favorite ways to fill out a collection. I can tell you from experience that deals for $1-2 per pound are commonly available on Craigslist. The last box I bought a few months back was from a 15 yr old. He was trying to save up for a car, and posted the box for $75.

    It was hard to tell what was really there from the picture, so I asked him to weigh it.  46 Lbs. That is $1.63 per pound, or about 1/2 cent per brick. (New Lego is generally .10-.15 per brick) I am excited to post what was in it soon, but let me tell you there were tons of great bricks.


    This isn't a rare find. I just flipped to Craigslist and here is a post with 4 x 20 Lb tubs for $160.  That is $2 per pound at the asking price. If you are ready to sort and organize your collection, I highly recommend grabbing 20-50 Lbs. of extra bricks for a low price. It will give you lots and lots more options to create. 

    Make Changes Or Add Bricks & Sets

    If I notice that the build I want to make, has a brick that we don't own, then my first step is to pull out the instructions.  Often when I look at how the brick is used, it becomes obvious that I don't really need that piece.

    An example is when we were building the Lego tower crane. I came across this piece we did not have. But after looking at the instructions, I realized it was just the roof on a building and there was an easy option that would fit and look great. This saved me from having to acquire a fairly rare brick. 

    Substitute Bricks

    If you can't work around the missing bricks then you will have to add them to your collection. This can come by buying sets, or buying bricks. Sets are the best choice if you can get a lot of the pieces you want in one model, and it is still in stock or relatively cheap. An example might be the LEGO City Space Deep Space Rocket 60228 If your custom Lego build has a long cylinder this could be a great source of curved orange and white bricks. 

    Lastly if you just can't find it anywhere else, there is Bricklink.com This isn't meant to be a knock, Bricklink is awesome. But unless you are buying large quantities from a few sellers, it is a very expensive way to buy bricks.

    Bricklink Pieces

    If you don't know, Bricklink allows sellers to post individual Lego elements for sale. You can search for the part number and see what sellers have it available. Most bricks are reasonably priced (1-50 cents per brick) and there are lots to choose from. The problem comes if there is not a single seller who has all of the bricks you need. This is because shipping is expensive.

    Many sellers on Bricklink are in Europe and shipping is usually $10 or more per package. If you are ordering a few hundred bricks, no big deal. If you only need 20 special parts and they are at 2 different sellers, well you are paying $1 per brick in shipping. Bricklink understands this and they have done a lot to make it easier to find the best sellers for you. If you run into a situation where you only need a few bricks from a seller, you can always look around at what else they have that you might want for future builds. 

    Building custom Lego sets can be one of the most fun and rewarding parts of being a Lego builder. It doesn't have to be expensive or complex with a little planning. A good sized bin of bulk Lego and an evening with the speed sorter can go a long ways to get you ready for some amazing Lego creations.  Aloha!

    Thanks for joining me today at the Build More Store. To see the latest articles make sure to check out the Lego Blog or for some great holiday activities make sure to browse our page on Lego Christmas. 


    David Tatera

    David was first introduced to the brick when his family took a vacation to Legoland in 1980. He spent the next 10 years building and creating till he put aside his toys for other interests. Recently those bricks came back into his life as a father of two. From there David developed the Sorted By Sunday system to help improve how his family built with Lego and created this site to share it with the world.

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