How to Plan and Build a Full Cosplay in 90 Days
Three months. That's the window most cosplayers are working with when they register for a major convention and realize they want to debut something new. It's enough time to do the job right, but only if you don't spend the first six weeks in planning paralysis and the last two weeks in panicked all-nighters.
This guide is the build plan you'll actually follow. It's structured around five phases that map to how a real costume comes together: planning, core construction, finishing, assembly and testing, and final prep. Whether you're tackling your first full armor build or your tenth, having a phase-gated timeline removes the guesswork and keeps momentum moving in the right direction.
We'll flag the shortcuts that are genuinely worth taking, and the ones that will cost you later.
Why 90 Days Is the Sweet Spot for a Cosplay Build
A 90-day window maps almost perfectly to the typical convention prep cycle. Most major conventions open pre-registration four to six months out, and cosplayers who are serious about a new build tend to lock in about three months before the event. That's your window.
Less than 60 days is risky. Complex armor builds with paint, weathering, and structural work simply need time. Not just hours, but calendar time, for paint to cure, for fit adjustments after wearing, for the inevitable mistake that needs a redo.
More than 120 days without structure leads to drift. Long timelines encourage procrastination. If the con is six months away, it feels like there's always tomorrow, until suddenly there's not.
90 days creates meaningful but manageable urgency. Each phase has defined start and end points, which makes it easy to know whether you're on track. And with the right material choices, 90 days is genuinely enough time to produce a professional-quality build, without burning yourself out.
This guide is also the hub connecting our full cosplay resource library. You'll find links throughout to deeper dives on specific topics: material selection, painting, attachment methods, costs, and convention-day planning.
Phase 1: Planning and Materials (Days 1–14)
The first two weeks don't involve touching a single piece of material. They're about making decisions, and making them deliberately, before you're too deep in the project to change course cheaply.
Choosing Your Character
Start with honest self-assessment. What character do you genuinely want to wear for a full convention day? Not just photograph, but walk around in, answer questions about, and feel excited to put on at 9am.
Consider how the character's armor design maps to your build skill level. Highly articulated suits with many small pieces require more assembly time and more careful fitting. Characters with large, geometric plate armor are generally more forgiving for builders at any skill level. Characters with organic, flowing elements may be better served by foam or fabric rather than rigid armor.
Don't let perfect be the enemy of good. A well-executed version of a character you love will always outperform an incomplete version of a character you chose for prestige.
Reference Gathering
This step is underrated and often skipped. Before you can build anything accurately, you need to know exactly what you're building.
Collect: in-game screenshots or cinematic stills from multiple angles, official concept art or model sheets if available, high-resolution photos of existing builds (especially competition-level work), and any orthographic reference you can find. If you're building from a video game character, use freecam mods or the game's photo mode to capture angles the camera normally wouldn't show.
Organize these references somewhere accessible, such as a folder on your phone, a Notion board, or printed sheets in your workspace. You will refer to these constantly throughout the build, and not having them handy when you're mid-cut costs time.
Material Selection
Your material choice shapes every subsequent decision in this timeline, including construction methods, tools needed, finishing process, and total build time. This is the decision worth spending real time on.
If you haven't already, read our full ABS vs. EVA foam comparison guide. The short version: ABS thermoformed armor is more durable, more forgiving for builders without foam-shaping experience, and holds up better across multi-day conventions and travel. EVA foam is lighter, cheaper in raw materials, and more flexible for organic shapes. Your character's design, your experience level, and your convention goals should drive this call.
For armor-heavy builds, particularly mechanical, military, or sci-fi aesthetics, thermoformed ABS is often the right call for exactly the reasons this timeline is designed around: it front-loads precision into the kit design, not into your hands.
Budget Planning
Before you order anything, know your number. Not a vague "I don't want to spend too much" number, but an actual figure.
Total cosplay costs include: base materials or kit, undersuit or base garment, attachment hardware (snaps, buckles, velcro, strapping), painting and finishing supplies, tools you don't own yet, transportation and storage solutions, and any accessories or props.
Our cosplay cost breakdown guide walks through all of these categories in detail with realistic ranges. Knowing your budget in Week 1 prevents the worst-case scenario: discovering in Week 6 that you can't afford the finishing supplies you need because you overspent on base materials.
Ordering Your Kit or Materials
Order early. This is non-negotiable.
Shipping delays, customs holds, and out-of-stock situations are all more common than people expect. Order your primary materials, whether that's a thermoformed ABS kit or raw EVA foam sheets, at the start of Week 2 at the latest. This gives you buffer if anything is delayed, and means your materials are on hand when Phase 2 begins.
If you're ordering from XposedDesigns, their US-based production and fulfillment means domestic shipping times are short. But even so: don't cut this one close.
Phase 2: Core Build (Days 15–45)
The core build phase is where the costume takes shape. It's the longest phase and the one most likely to run over schedule if you're not watching your time. Thirty days sounds like a lot, and it's not, if you're working on weekends only.
Aim for consistent sessions rather than marathon weekends. Two to three hours on Tuesday and Thursday beats eight hours on Saturday if it means you're making weekly progress.
Assembling Armor Pieces
With a pre-formed ABS kit, this phase is primarily about joining pieces correctly and building out the structural foundation. Work section by section, and don't try to assemble everything at once. Torso first, then limb sections, then extremities.
Use your reference images constantly. Dry-fit every piece before any permanent join. It takes more time upfront, but it eliminates the far costlier problem of discovering a misaligned piece after it's been glued.
Mark all pieces clearly on the interior, noting left/right, top/bottom, and orientation. In a complex build with dozens of pieces, visual similarity between left and right components will cause errors that are obvious only in retrospect.
Fitting and Adjustment
At the end of each major section, put the assembled pieces on and wear them for fifteen minutes. Walk around. Sit down. Raise your arms. Note every restriction, hot spot, and awkward edge.
Fitting adjustments are fast and easy at this stage. They are slow and frustrating at Stage 4. Do this now.
Photograph yourself wearing each section. Front, back, and both sides. Compare these to your reference images. Small geometry issues that aren't visible in your hands become obvious in photos.
Structural Reinforcement
Before Phase 3 begins, every piece needs to be structurally sound. That means all joints are solid, no flex or movement where there shouldn't be, and the build can be handled firmly without anything shifting.
For ABS armor, reinforce any long seams or stress points on the interior with epoxy or additional plastic adhesive. This is invisible in the final build and prevents the embarrassment of a seam failure on the con floor.
Phase 3: Finishing (Days 46–70)
Finishing is where the build transforms from assembled pieces into a costume. It's also the phase where impatient builders lose the most ground, as rushing paint, skipping cure times, or skimping on surface prep produces results that look rushed. They always do.
Sanding and Surface Prep
Before any paint touches any surface, every piece should be sanded. Start with coarser grit (180–220) to remove any tooling marks, mold lines, or seam filler ridges. Progress to finer grit (320–400) for a smooth base.
Wipe all surfaces clean with a tack cloth or isopropyl alcohol before priming. Any dust, oil from your hands, or loose material will show up under paint.
Priming
Primer is not optional. It creates the adhesion layer that holds your paint, reveals any surface defects you missed during sanding, and gives your base coat a consistent surface to grab.
For ABS, use a plastic-formulated spray primer. Apply in thin, even coats, as two light coats are better than one heavy coat. Let each coat flash off fully before applying the next. Don't rush this.
After priming, do a visual check of every surface in raking light. Any remaining scratches, dips, or seam lines will be clearly visible now, when they're easy to address. Address them.
Painting
Painting is a full topic that warrants its own deep dive. See our complete guide to painting ABS cosplay armor for technique walkthroughs, product recommendations, and step-by-step approaches for different finish types.
The key principles: thin coats, proper flash time between coats, patience at every step. A rushed paint job is visible to everyone. A carefully executed one looks like professional work.
Plan your painting schedule backward from your target finish date. Factor in dry time between coats, not just application time.
Weathering and Detail Work
Weathering makes armor look lived-in and real rather than freshly painted and plastic. For armor-style builds, even subtle weathering (edge wear, directional grime, scratches, and shadow) dramatically increases visual quality.
Work from dark to light. Apply dark wash into recesses first, then drybrush edges with a lighter color to simulate wear. Add scratches with a fine brush and metallic paint. Step back frequently and compare to your reference images.
Weathering is the step where you can get lost in a satisfying rabbit hole. Set a time limit if you need to. Good weathering done in two hours is better than perfect weathering that eats your entire finishing phase.
Phase 4: Assembly and Testing (Days 71–85)
By now you have finished, painted armor pieces. Phase 4 is about turning those pieces into a wearable costume and stress-testing it before the con.
Attachment Methods
How your armor attaches to your body is a structural engineering problem as much as a construction one. The wrong attachment system leads to drooping pieces, failed closures, and uncomfortable wear, none of which you want to discover mid-convention.
Our complete guide to attaching armor to a bodysuit covers every major approach: snap plates, chicago screws, barge cement, velcro (and why it fails more often than people expect), and elastic and buckle systems. The right choice depends on your armor weight, base garment, and how frequently you'll need to don and doff.
Build your attachment system with removal in mind. You will need to take this costume apart, for storage, for travel, for repairs. Permanent solutions that make that difficult will create problems down the line.
Comfort Testing and Wear Time
Put the full costume on and keep it on for at least four hours. Not for photos, just wear it. Do normal things. Sit, stand, walk, climb stairs, eat something.
Note every discomfort point: sharp edges that dig in, pieces that shift out of position, areas that restrict breathing, attachment points that pull or strain. Every one of these is fixable now. None of them should surprise you on convention day.
Mobility Check
Run through a full range of motion while wearing the full build. Arms over your head, crouching, turning side to side. Identify any pieces that bind, any seams that stress under movement, and any attachment points that pull loose under extension.
For armor-heavy builds, you will almost certainly discover some adjustments needed here. That's why this phase exists. Address them before the final phase.
Phase 5: Final Prep (Days 86–90)
The last five days are not for new construction. They're for protecting everything you've built and making sure convention day goes smoothly.
Touch-ups and Repairs
Address the punch list from comfort testing and mobility checks. Touch up any paint chips from construction and assembly. Reinforce any attachment points that showed stress. Check every seam.
Resist the urge to make major changes at this stage. Small improvements are appropriate; design rethinks are not.
Packing for Travel
How you pack your armor is as important as how you build it. Rigid ABS benefits enormously from structured packing: dedicated bins or hard-sided cases, foam padding around each section, and careful arrangement that avoids pressure on finished surfaces.
Label every container. If you're flying, rigid armor pieces in checked luggage need extra padding. If you're driving, keep temperature in mind, as direct sun through a car window can warp materials over a long drive.
If you're attending a multi-day convention, bringing a small repair kit is worth the bag space: matching paint pens, fast-drying adhesive, spare snaps or velcro squares, and a small flashlight for doing quick inspections in dim con spaces.
For convention day travel strategy and packing lists, our Dragon Con planning guide has detailed advice that applies to any major convention, not just Dragon Con.
Convention Day Checklist
Prepare this in the final days before the convention, not the morning of:
- Full costume on and checked: all pieces secured, no loose attachment points
- Repair kit packed and accessible (not buried in checked luggage)
- Undersuit and base layer clean and staged
- Transportation plan confirmed: if ridesharing, are you fitting in the vehicle in costume or changing on-site?
- Convention schedule reviewed: know which hours have high traffic and when you'll want to take the costume off
- Designated safe storage location at the hotel or venue for pieces you remove during the day
- Water bottle and snacks you can access while in costume
The goal on convention day is to enjoy the experience, not manage a crisis. A 90-day build that was planned and executed properly means the costume works, and you can focus on the fun part.
Shortcut: Start with a Pre-Formed Kit
If any part of Phase 2, specifically the shaping, forming, and structural build work, feels like the most daunting part of this timeline, there's a legitimate shortcut that doesn't compromise the end result.
Thermoformed ABS armor kits, like those made by XposedDesigns, arrive as pre-shaped pieces ready for assembly. The forming work (the part that requires specialized tooling and practiced technique) is already done. You show up at Day 15 with finished geometry in hand rather than raw flat material.
This compresses Phase 2 from 30 days to closer to 10–15, without sacrificing any of the creative work in Phase 3. Your painting, weathering, and detailing is entirely your own. The build timeline gets dramatically more manageable, and the structural results are more consistent than hand-formed alternatives.
XposedDesigns kits are US-made from thermoformed ABS, come in DIY unassembled, assembled, and assembled-and-painted tiers, and carry a 4.9-star average from a large review base. Current kits include the NCR Veteran Ranger armor set, the T-51B power armor kit, the Combat Armor kit, and the Dragon Priest Mask.
Browse the full catalog at xposeddesigns.com, and if you're early in the planning process, the DIY unassembled tier is the best starting point for builders who want to own the finishing work.
Ninety days is enough time to produce something you're genuinely proud of. The builds that fall apart, either literally on the con floor, or figuratively when the owner runs out of steam, almost always fail in the planning phase, not the build phase. Get that right first, and everything downstream gets easier.
Good luck. Come back and show us what you made.