If you own an older board game with a broken insert, missing tray, or no organizer at all, you have probably hit one of the most frustrating hobby crossroads: nobody makes a custom insert for your game, and the original setup is a mess. I have been there more times than I can count, and the honest answer is that this is a great opportunity to build one yourself. A custom retrofit insert costs a few dollars, takes an afternoon, and finally makes that old game worth playing again.
This guide walks you through how to retrofit an old game with a custom insert when no commercial one exists. I will cover the materials, the measuring, the cutting, and the assembly, plus what to do when the original insert is still partially in the box. By the end, you will know exactly how to build a foam core or 3D printed insert that fits your specific game, your sleeves, and your cleanup time.
Table of Contents
Assess Your Game Before Starting
Before you cut a single piece of foam core, you need a complete picture of what you are working with. I learned this the hard way after designing an insert that did not account for one stray token, and the entire layout had to be rebuilt. Start by asking four questions about your game.
What is the inside of the box really like?
Open the box and measure the interior length, width, and depth. Use a metal ruler and write the numbers down in millimeters. Do not trust the box dimensions listed on the website, because lid thickness and internal shelf height vary by print run. If the original insert is still in there, measure its footprint and note where it sits relative to the lid.
Is the original insert salvageable or does it need to go?
If the original insert is broken, warped, or unusable, remove it entirely. Trying to retrofit around a half-broken tray usually creates more problems than it solves. If it is mostly intact but you hate how it organizes components, you can leave it in and layer a smaller insert on top, but only when the box height allows it. We are focused on the full retrofit scenario here, so plan to remove the original.
What components need their own space?
Dump everything out and group by component type: cards, tokens, dice, miniatures, player boards, rulebooks, and any odd-shaped pieces. Sleeved cards are a special case that I will cover in the planning section, because they usually need 1 to 3 extra millimeters of space per compartment. Count how many decks you have and how many separate piles of tokens exist.
How much lid lift can you tolerate?
Lid lift is the small gap that forms when the contents plus the insert sit taller than the box depth. A tiny bit of lid lift is fine and even helps with setup. A lot of lid lift causes components to jump around when you pick up the box. Aim for zero lid lift on the main insert and accept a small amount if you stack pieces on top.
Materials and Tools You Need
The full foam core kit for a retrofit insert is cheap and mostly reusable. I have built inserts for under $20 total, and the tools lasted through a dozen projects. Here is what you actually need, not what the YouTube thumbnail suggests.
Foam core board
Buy 5mm foam core as your default. It is the industry standard for board game inserts and balances rigidity with cuttability. Pick up 3mm foam core only for thin dividers and card spacers. Most craft stores carry black or white foam core in 20 by 30 inch sheets. One sheet covers most medium-sized games. 10mm foam core exists but is harder to cut cleanly and rarely needed.
Cutting tools
You need three cutting tools and one surface. A sharp craft knife with snap-off blades is mandatory. Replace the blade every two games or whenever it starts to drag. A metal ruler at least 12 inches long acts as your straight edge and prevents the knife from wandering. A self-healing cutting mat protects your table and gives you a grid for accurate measurements. A scoring tool, which can be a dull knife, a stylus, or a bone folder, is helpful for clean folds but optional.
Adhesives
Hot glue is the most common choice because it dries fast and holds strong. Low-temp hot glue guns are safer but need a few extra seconds to set. White PVA glue works but takes longer to cure and can warp thin foam core if overused. Super glue is overkill for foam core and can melt the surface. Foam core specific glue exists, but a basic glue stick or PVA will give you a strong, repositionable bond for the same price.
Other supplies
Keep a pencil, eraser, black marker, and a small notepad on hand. A digital caliper under $15 is a huge upgrade if you plan to do this regularly. Painter’s tape helps hold pieces together during dry fitting. A flat piece of cardboard or a small box can serve as a temporary test surface.
Budget breakdown for a typical retrofit
One sheet of 5mm foam core runs $3 to $5. A craft knife with extra blades is $5 to $10. A cutting mat is $10 to $20 but lasts years. A hot glue gun costs $5 to $15. Total for a first-timer is around $25 to $50, and every project after that is just the foam core plus a few glue sticks. Compared to commercial inserts, which often run $20 to $50 per game, the savings are real.
How to Plan and Measure Your Custom Insert?
Planning is where most beginners lose time, and it is also where I have learned to slow down after too many weekend mistakes. Give yourself at least an hour for the planning stage before any cutting. The actual cutting takes 30 minutes. The thinking takes much longer.
Step 1: Sketch the box interior
Draw a top-down rectangle of the box on a piece of paper. Mark the dimensions in millimeters. Add the depth number somewhere visible. This drawing becomes your master plan, and you will refer back to it every time you cut a piece.
Step 2: List every component with its dimensions
For each group of components, note the length, width, height, and quantity. Cards are easy at about 59 by 91 millimeters, but sleeved cards add roughly 1 to 2 millimeters per card. Tokens and dice vary wildly. Measure the tallest stack, because that determines the height of your tallest compartment.
Step 3: Block out compartments on the sketch
Use rough rectangles to allocate space for each component group. Leave at least 2 millimeters of clearance around each compartment so pieces slide in and out easily. Larger components like rulebooks and player boards get their own dedicated zones. The goal is to fit every component into the box with no wasted space.
Step 4: Plan for sleeved cards and expansions
If you sleeve your cards, build your card compartments tall enough to hold the full deck with sleeves on. If you plan to add expansions later, leave an empty zone near the edge of the box that can be filled later. Many retrofit inserts are designed to accommodate a future expansion, and this small bit of foresight saves you from rebuilding the entire insert.
Step 5: Account for the base layer
Your insert will sit on a base layer of foam core that covers the entire box bottom. This base adds 5mm to the effective height of every compartment, so subtract that from your lid clearance before sizing anything. If the base is too thick, switch to 3mm foam core for the base layer. This is the most common beginner mistake I see, and it always shows up as lid lift.
Cutting Techniques for Clean Foam Core Pieces
Cutting foam core is satisfying once you get the feel for it. The trick is to treat the cut as a multi-pass process rather than a single deep slice. Here is the workflow I use for every piece.
Mark the cut line clearly
Use a metal ruler and a pencil to mark your cut. Double-check the measurement before you commit. A piece cut 2mm short is salvageable. A piece cut 2mm long has to be redone. Mark both ends of the line and connect them with a faint pencil stroke across the foam core surface.
Score first, then cut
Press the ruler firmly against the foam core and run the craft knife along the line with light pressure. This first pass scores the top paper layer and creates a guide. Take a second pass with slightly more pressure, then a third pass that cuts all the way through. Three passes beats one deep cut every time. The result is a clean edge with no tearing.
Cut on a cutting mat, not on the table
The cutting mat grid helps you align pieces without remeasuring. It also protects your knife blade and your furniture. A dull blade is the number one cause of rough cuts and crushed edges, so swap in a fresh blade whenever the cut starts to drag.
How to make foam core curve for round or angled sections
Some retrofits need compartments with curved corners or angled walls to fit a specific game component. To curve foam core, score the surface deeply along the line where you want the bend, then bend slowly. The deeper you score, the tighter the curve. For a smooth curve, make multiple parallel scores about 5mm apart, then bend the strip. The result is a flexible piece that holds its shape, useful for round token wells or angled dividers.
Cut internal windows after the main frame
For compartments that need a hollowed-out window, cut the outer frame first, then trace the inner window on the back of the piece. Use the craft knife to cut the inner window from the back, applying lighter pressure to avoid cutting through the front paper. This approach prevents the front face from getting torn or wrinkled.
Safety basics
Always cut away from your body and keep your non-knife hand on the ruler, not in the path of the blade. Snap off blade segments when they dull rather than reusing a tired blade. Work in a well-lit area so you can see the cut line clearly. A small first aid kit nearby is not a bad idea when you are doing a long cutting session.
Assembly, Gluing, and Testing the Fit
Now you have a stack of cut pieces and the moment of truth: do they actually fit together? This is where the retrofit goes from a pile of foam core to a working insert. Take your time here, because a half-hour of testing saves a half-hour of rebuilding.
Dry fit everything before gluing
Assemble the insert inside the box without any glue. Use small pieces of painter’s tape to hold joints together temporarily. Put all the components in their compartments and close the lid. If the lid does not close, trim walls. If a component does not fit, adjust the compartment. Only proceed to glue once the dry fit is perfect.
Choose the right glue for the job
Hot glue is the best choice for foam core inserts because it grabs in seconds and holds well. Apply a thin bead along the joint and press the pieces together for 10 seconds. White PVA glue works for permanent bonds but takes 30 minutes to cure and needs clamps. I use hot glue for 90% of retrofits and switch to PVA only when I want extra time to align pieces.
Glue in a logical order
Start with the base layer. Glue the outer walls to the base, then add internal dividers. Work from the largest pieces to the smallest. Doing it in this order means each new piece has something solid to press against. Gluing tiny pieces first is a recipe for burned fingers and crooked joints.
Prevent lid lift with the final fit test
After gluing, put every component back in the insert and close the lid. The lid should sit flush with the box. If there is any gap, identify the tallest compartment and trim 1mm at a time until the lid closes. A perfectly fitted insert should have zero lid lift on the main level, though a tiny bit of play on the top layer is acceptable and helps with setup.
Add finishing touches
Black marker on the cut edges hides the foam core color and makes the insert look more professional. A small dot of hot glue on each corner reinforces the joints. If you want to take it further, you can add felt lining, but most retrofits look great without it. The functional goal is what matters: every component in its place, no lid lift, quick setup.
Alternatives to Foam Core: 3D Printing and Other Options
Foam core is not the only material, and for some games it is not even the best choice. When I am retrofitting an old game with complex shapes, repeated prints, or a particularly sturdy feel, I consider alternatives.
3D printed inserts
3D printing gives you curved walls, built-in finger holes, and stackable trays that foam core cannot match. If you have access to a printer or a local library with one, you can download free insert designs from sites like Thingiverse or Printables for many popular games. The printer cost is the barrier for most hobbyists, but a single print can replace hours of cutting. For a retrofit where no commercial insert exists, 3D printing shines because you can design or download something specific to your game.
Foam core vs 3D printing cost comparison
Foam core for a single insert costs $3 to $5 in materials. 3D printing at a service like Shapeways or through a local makerspace runs $20 to $60 for a comparable insert, depending on size and material. Foam core wins on price for one-off projects. 3D printing wins on durability and visual quality for projects you will keep forever. Many serious hobbyists use both, foam core for quick prototypes and 3D printing for the final version of a favorite game.
Other materials worth considering
Cardboard from old game boxes or shipping boxes can be layered and glued for a free retrofit. Balsa wood is great for thin dividers and miniature trays but adds cost. Laser-cut MDF inserts are available for some games and look stunning, though they cost more than foam core. For most retrofits of older games, foam core is still the sweet spot of cost, tool requirements, and visual result.
When to upgrade the original insert instead of replacing it
Sometimes the original insert is mostly fine but missing a few pieces. In that case, retrofit by adding foam core trays on top of the original. This works well for games with tall boxes where full replacement is overkill. You can also 3D print a few replacement trays to fill the gaps in the original plastic insert. The goal is always the same: organize the components so setup is fast and storage is clean.
FAQs
How do you make custom foam inserts for board games?
Start by measuring the interior of your box and listing every component with its dimensions. Sketch a layout with compartments for each component group, allowing 2mm of clearance on each side. Cut foam core pieces using a craft knife, metal ruler, and cutting mat. Dry-fit the pieces in the box, then glue them together with hot glue for a permanent insert.
What are the disadvantages of using foamcore for game inserts?
Foam core is less durable than 3D printed or plastic inserts and can dent or tear under heavy use. Cut edges are visible and often need to be touched up with a marker. Foam core does not hold screws or magnets well. For games stored vertically or transported often, a sturdier material may be a better long-term choice.
What glue is best for foam core board game inserts?
Hot glue is the most popular choice because it grabs in seconds and creates a strong permanent bond. Low-temp hot glue guns are safer and still effective. White PVA glue works for permanent bonds but takes 30 minutes to cure and needs clamps. Avoid super glue, which can melt foam core and damage the surface.
How do you make foam core curve for round compartments?
Score the foam core deeply along the line where you want the curve, then bend slowly. For tighter curves, make multiple parallel scores about 5mm apart before bending. The deeper the score, the sharper the curve. This technique is useful for round token wells, angled dividers, and shaped compartments that straight cuts cannot achieve.
Conclusion
Learning how to retrofit an old game with a custom insert when no commercial one exists is one of the most rewarding hobby skills you can pick up. You will save money, breathe new life into forgotten games, and end up with an insert that fits your exact setup and storage needs. Start with the assessment, gather your materials, plan your layout, and take the cutting slowly. Your next game night will run smoother because of it.