*** SPECIAL NOTICE *** Carbon Rod products have been out of stock for many weeks. Why?
Our supplier of carbon fiber rod has discontinued the fabrication of continuous master spool runs. The longest rod length is now available in 12 foot (3.65 m) lengths or less.
This has completely disrupted our ability to supply our customers with 100 foot (30.5 m) spools as described below. We apologize and are actively seeking alternative suppliers.
Until further notice, we are unable to sell any carbon fiber rod products. –Sean Marske
Solid Round 0.125” Micro Pultruded Carbon Rod
MADE IN THE USA
Our micro pultruded solid carbon rod is a high-strength, lightweight material extensively discussed in the Composite Design Manual by Jim Marske.
With its exceptional mechanical properties, it is widely used in composite structures, including aircraft wing spars, reinforcements, and other high-performance applications requiring strength and stiffness with minimal weight.
Why Choose Our Micro Pultruded Solid Round Carbon Rod?
Engineered for precision, strength, and minimal weight, our 0.125″ micro pultruded solid carbon rod is the result of decades of applied experimentation and composite design refinement by Jim Marske.
As detailed in his Composite Design Manual, this material plays a critical role in modern composite construction, particularly in aircraft wing spars and other structural elements where performance per weight is paramount.
Manufactured in the USA using a continuous fiber pultrusion process, this rod delivers exceptional stiffness and tensile strength in a compact form factor. Their consistent quality and proven reliability make them ideal for demanding applications where traditional reinforcement materials fall short.
Whether you’re designing high-efficiency wing structures or reinforcing advanced composite assemblies, this carbon rod offers the mechanical advantage needed to push your designs further.
Key Properties
- High Strength-to-Weight Ratio: The pultruded manufacturing process results in a highly efficient material with superior tensile strength compared to metals of similar weight.
- Unidirectional Fiber Orientation: Unlike woven composites, micro pultruded rods have all fibers aligned along their length, maximizing strength along the primary load path.
- Low Density: Carbon fiber materials weigh significantly less than steel and aluminum while providing comparable or superior mechanical performance.
- Corrosion Resistance: Unlike metal alternatives, these rods do not corrode, making them ideal for long-term applications in aerospace, marine, and structural engineering.
- Minimal Creep or Deformation: The high modulus of elasticity ensures minimal elongation.
Advantages in Composite Applications
- Aircraft Wing Spar Reinforcement: Jim Marske’s work in the Composite Design Manual demonstrates how micro pultruded solid carbon rods enhance the load-carrying capacity of composite wing spars. By embedding these rods into spars, designers achieve significantly higher strength with lower weight than traditional aluminum or wood structures.
- Fatigue Resistance and Longevity: Carbon fiber does not suffer from fatigue and material degradation like metals. This property ensures that structures reinforced with micro pultruded solid carbon rods maintain their performance over extended service lives, reducing maintenance costs.
- Stiffness Optimization in Composite Panels: By integrating 0.125″ round carbon rods into composite panels, designers can fine-tune stiffness without adding excess weight. This feature is critical in aircraft structures, where minimizing deflection while maintaining a lightweight design is essential.
- Simplified Fabrication and Bonding: Unlike woven laminates, which require complex layups, micro pultruded rods can be embedded directly into epoxy or resin systems. Their precise dimensions allow for easy bonding into composite structures without extensive machining or finishing.
Minimum Specifications of 0.125” Solid Round Micro Pultruded Carbon Rod
Tensile Strength |
320 ksi (2.34 GPa) |
The maximum stress the rod can withstand when stretched before breaking. |
Tensile Modulus |
19.5 msi (134 GPa) |
A measure of stiffness in tension, indicating how much the material resists stretching. |
Compressive Strength |
270 ksi (1.90 GPa) |
The maximum stress the rod can withstand when compressed before failure. |
Compressive Modulus |
19.0 msi (131 GPa) |
A measure of stiffness in compression, showing resistance to deformation under compressive load. |
Fiber Volume |
67% |
The percentage of carbon fiber content in the composite, affecting strength and stiffness. |
Ultimate Tensile Strain |
1.30% |
The maximum elongation before failure, representing ductility. |
Diameter Tolerance |
±5% |
The allowable variation in rod diameter, ensuring consistency in manufacturing. |
Glass Transition Temperature |
100°C |
The temperature at which the matrix material softens, influencing thermal performance. |
Matrix Material |
Bis-F Epoxy |
The epoxy resin used to bond carbon fibers, providing durability and environmental resistance. |
Bonding Micro Pultruded Solid Round Carbon Rod
Proper bonding of micro pultruded solid carbon rods is essential for achieving optimal structural performance. The Composite Design Manual provides detailed guidance on selecting the correct epoxy and application techniques.
Selecting the Right Epoxy
Epoxy vs. Polyester Resins – Epoxy resins provide superior adhesion, mechanical strength, and resistance to environmental degradation compared to polyester resins. While polyester resins are more economical and easier to work with, they tend to have weaker bonding strength and higher shrinkage, which can lead to stress fractures in high-load applications.
The Composite Design Manual strongly recommends using epoxy resins for bonding micro pultruded solid carbon rods due to their durability and long-term stability in structural applications.
- Use a high-quality structural epoxy with a low viscosity to ensure thorough wetting of the rod and bonding surface.
- Avoid brittle adhesives—opt for epoxy formulations with moderate flexibility to account for thermal expansion and vibration stresses.
- Ensure compatibility with composite laminates to prevent delamination or weak bond joints.
Surface Preparation
- Lightly abrade the surface of the carbon rod using fine-grit sandpaper or Scotch-Brite to remove any manufacturing residue and improve adhesion.
- Clean the rod thoroughly with acetone or isopropyl alcohol to remove dust and oils before bonding.
- Avoid touching the cleaned surface to prevent contamination.
Application Technique
- Apply a thin, even layer of epoxy to both the rod and the bonding surface.
- If embedding the rod into a groove, ensure the epoxy fully fills any gaps to prevent voids.
- Use clamping or moderate pressure to hold the rod in place while the epoxy cures, avoiding excess force that could squeeze out too much adhesive.
- Follow the manufacturer’s recommended curing schedule, typically at room temperature or slightly elevated heat for optimal strength.
