Every carbon fiber tube, sheet and machined part starts as liquid epoxy. Whatever is dissolved in that liquid — air, moisture, volatiles — ends up inside your part unless it is removed first.
Bubbles trapped in cured resin become voids. Voids act as stress concentrators: interlaminar shear and flexural strength drop measurably as void content rises. Industry studies commonly link just 2–4% void content to double-digit strength loss in layup composites.
Air in the resin shows up as pinholes, pockmarks and dull patches on gloss surfaces — the fastest way to lose a show-part or cosmetic-panel customer, no matter how good the fiber is.
Connected voids create leak paths in tubes and pressure parts, and each bubble is a crack-initiation site under cyclic load. Drone arms, RC chassis and robotics booms all live or die by fatigue life.
Voids exposed by CNC cutting mean scrapped parts after expensive machining time. Degassing resin upstream is the cheapest quality insurance in the workshop.
The resin cup sits inside a sealed chamber connected to a vacuum pump. The pump pulls the chamber down to roughly -0.095 MPa (close to full vacuum).
Per Henry's law, the lower the pressure, the less gas the resin can hold. Dissolved air comes out of solution and existing micro-bubbles expand to several times their size.
Bigger bubbles mean more buoyancy: they climb to the surface fast, where they rupture and vent to the chamber instead of staying in the pour.
After a few minutes (thin resin) to half an hour (highly filled or viscous systems), the resin is void-free and ready for casting, infusion or wet layup.
| Process Step | What We Degas | What It Prevents |
|---|---|---|
| Wet lay-up & resin casting | Mixed epoxy used before laminating, casting or potting | Void rings and weak interlaminar zones in the cured part |
| Sheet & plate pressing | Resin film / wet resin between plies | Surface pinholes on gloss sheets, delamination risk |
| Vacuum infusion | Resin in the trap pot before it enters the line | Air carried into the fiber bed, dry spots and porosity |
| Casting & potting | Filled epoxy for inserts, joints and fittings | Sink marks, voids around embedded hardware |
| Prototype samples | Small batches before any full production run | Quality surprises discovered after tooling is committed |
A sealed tank, a vacuum pump and patience. The resin simply sits while bubbles escape. Low cost, large capacity, ideal for low-to-medium viscosity laminating epoxies — the standard choice for carbon fiber sheet and tube production.
The cup both revolves and rotates while the chamber is under vacuum — mixing and degassing happen together, with no stirring blade to whip in new air. Minutes instead of half-hours, best for high-viscosity or filled systems, adhesives and battery-type slurries.
Vacuum degassing (also called vacuum defoaming or de-aeration) places freshly mixed epoxy resin inside a sealed chamber while a vacuum pump lowers the pressure to around -0.095 MPa. Dissolved air comes out of solution, micro-bubbles expand, rise to the surface and burst, leaving void-free resin for casting, infusion or layup.
Trapped bubbles cure into voids inside the composite. Voids are stress concentrators that reduce interlaminar shear and flexural strength, create leak paths in tubes, and serve as crack-initiation sites under fatigue loading. They also show up as pinholes and pockmarks on gloss surfaces.
Typically 5-15 minutes for low-viscosity laminating epoxy, and up to 30 minutes for highly filled or viscous systems. Degassing is done after mixing in the hardener and before the resin approaches gel — fast-cure hardeners may require chilled resin or smaller batches.
Yes — that is the normal sequence for wet layup and infusion: mix resin and hardener thoroughly, degas the mixed batch, then cast or infuse. For very fast hardeners, keep the pot small so the exotherm does not cut the working window short.
Serious ones do. Skipping degassing saves a few minutes per batch but risks voids, surface pinholes, machining scrap and field failures. For structural tubes, gloss sheets and machined parts, degassed resin is a low-cost quality step that protects the entire downstream process.
No. Vacuum bagging compacts the layup and draws resin through the fiber during curing. Vacuum degassing removes trapped air from the liquid resin before it ever touches the fiber. The two processes complement each other — the best parts come from resin that is degassed first, then bagged or infused.
