Note
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- Introduction and Design Considerations
- Materials and Tools Required
- Printing Parts in PLA+
- Preparing Carbon Tubes
- Mold Preparation and Waxing
- Mixing and Applying Resin and Carbon Fiber
- Curing and Extraction
- Sanding and Fixing Impurities
- Assembly, Painting, and Drying
- Conclusions
- Costs
- Models / Files
- FAQs
This guide details the process for manufacturing a custom exterior part in carbon fiber for an Airsoft M4. It outlines each step to achieve a professional result. The part includes a complex internal component that secures the tube to the RIS while allowing the hop-up insertion. This component poses manufacturing challenges due to its protrusions and variable dimensions, requiring extreme precision.
The tube length depends on the design requirements, and precise cutting is essential for proper integration. Additional reinforcement, such as countersunk screws, may also be considered to increase durability and resistance.
Materials:
- PLA+ for 3D printing.
- High-quality carbon tubes (50 cm).
- Epoxy resin (40% resin, 60% carbon fiber).
- Carbon fiber in rolls or pre-cut.
- Mold wax (EasyComposites brand recommended).
- "Soft Filleting and Filling Wax" putty.
- Two-component epoxy adhesive.
- Protective paint or lacquer.
- Cooking film
Tools:
- 3D printer (e.g., Ender 3 Pro or others).
- Rotary tool (like Dremel) with a stand / Hand saw is also an option.
- Sandpaper (grits 80 to 240).
- Small brushes for applying resin.
- Plastic wrap.
- Clamps for applying pressure.
- Oven (optional, depending on the resin used).
Model parts are printed using PLA+ for its ease of handling. The printer used is an Ender 3 Pro, configured with a layer height of 0.15mm to achieve precision and speed. 3D modeling and subsequent printing allow precise prototyping and mold creation.
The process for creating the mold for the suppressor tip involves designing a model with a base, cap, pin, centering pins, and a locking washer. The final shape is cubic to ensure precise molding. Parts are printed individually to allow measurements and quality checks.
Before starting the cutting process, ensure you have the proper tools. You can use a traditional saw, although carbon is not easily cut this way. The most recommended option is a rotary tool like a Dremel. Personally, I use a Teccpo model with an extension cable.
To achieve precise and clean cuts in the carbon tube, I designed a stand that securely holds the tube and allows it to rotate for straight cuts. The Dremel's extension cable connects to the main handle, and the tube is held in place with clips. At the base of the stand, there are four wheels to facilitate tube rotation for precise and clean cuts.
Once you have cut the tube to your specifications, check the edges to ensure they are smooth and free of splinters.
In the following video, I have documented the cutting process using the Dremel and the designed stand, providing a clear idea of how to perform this crucial step in creating your own M4 stock.
To facilitate extraction and achieve a smooth surface, wax is applied inside and outside the mold.
- Inside: Manual application of wax, preferably EasyComposites brand, to achieve a smoother surface and prevent the visibility of 3D printing layers.
- Outside: Spray wax is used to remove excess resin.
Once all mold parts are prepared, they are secured using long screws. To prevent material from sticking to the screw heads, "Soft Filleting and Filling Wax" putty is used as a protector. This step is essential to avoid imperfections in the finish.
Epoxy resin is mixed in a 40% resin to 60% carbon fiber ratio. To calculate the required amounts, the following formula is used:
grams = cubic millimeters × 0.001
For example, for a part with a volume of 3034 mm³:
percentage * amount / 100
60% * 3.034g = 1.8204g (carbon fiber)
40% * 3.034g = 1.21g (resin)
Application:
- Apply an initial layer of resin with a brush.
- Manually adjust the carbon fiber with a stick.
- Alternatively, mix the carbon fiber directly into the resin and apply the mixture to the mold.
The resin and carbon fiber layers are applied to the mold sequentially. The first method involves applying an initial resin layer with a brush and manually adjusting the carbon fibers with a stick to cover all areas and gaps.
In the second method, carbon fibers are directly mixed in the same container where the epoxy mixture was prepared. Once impregnated, these are introduced into the mold, adjusting positions with a stick to ensure all spaces are filled.
The assembly is then wrapped with plastic wrap and secured with clamps to apply uniform pressure. This helps eliminate excess resin and improves cohesion.
Initial curing takes approximately 12 hours. Then, the parts are carefully removed from the mold and left to harden for another 12 hours to reach their final strength. Optionally, an oven can be used, following the epoxy resin manufacturer's instructions, as each product has its own temperature and time requirements.
The parts are sanded with progressively finer sandpaper (80 to 240 grit) to remove imperfections. Impurities are fixed using:
- Additional epoxy resin.
- Epoxy glue.
- Suitable filler material.
The parts are assembled using high-strength epoxy adhesive (fast or slow-drying, as needed). Then, layers of paint or protective lacquer are applied to enhance and protect the surface. Finally, allow the piece to dry completely before conducting any tests or further adjustments.
By following this process, you can manufacture a custom carbon fiber part for an Airsoft M4 with a professional finish. The selection of materials and attention to detail are essential for the project's success. Always prioritize safety and precision in every step.
| Material | Unit | Cost |
|---|---|---|
| Carbon Tube | 1 | €9.05 (-20%) |
| 12mm CW to 14mm CCW Aluminum Adapter | 1 | €0.92 |
| HSS Right-Hand Thread Tap | 1 | €3.37 |
| Miracle Gloss Mould Release Wax | 1 | €7.55 |
| Soft Filleting and Filling Wax | 1 | €7.15 |
| Epoxy Resin | 1 | €59.99 |
| Epoxy Glue | 1 | €5.21 |
| 200g 2x2 Twill 3k Black Stuff Carbon Fibre (1000mm) | 1 | 53,11€ |
| TOTAL | 3 | 146,47€ |
** It can be made cheaper by purchasing the EasyComposite kit: Repair kit
The models are paid and can be found here: Cults3D
- Why are they paid?
- I have dedicated time to writing this article, spent time printing and testing parts to give you everything ready...