Integrated Infusion Build: Marine Hull Panel with Full Documentation

Integrated Infusion Build: Marine Hull Panel with Full Documentation

This lab is your capstone infusion exercise. You will work alone — from bare mold to inspected part — and produce documentation that mirrors what a production composite shop submits with every structural marine panel. Accuracy in both the laminate and the paperwork is the professional standard the industry expects and what ACMA CCT and ABYC composite credentials test.

Why Documentation Matters in Marine Composites

A boat hull carries human lives. Regulatory bodies, surveyors, and insurance underwriters all expect that a builder can demonstrate — after the resin has cured and the mold is pulled — exactly what materials went in, at what temperature, mixed at what ratio, and inspected by whom. The production traveler, batch record, and process log are how that proof exists. In a certified shop, an incomplete batch record is treated the same as a nonconforming part: it stops production.

Your documentation package for this lab consists of three forms:

• Batch record — material lot numbers, mix ratio, pot quantity, ambient temperature and humidity at pour time, calculated and observed gel time.
• Process log — timestamped entry for every significant event (vacuum bag sealed, leak test passed, resin introduced, flow-front photos, resin-line pinched, vacuum maintained through gel, cure start, demold).
• Written summary — one-page narrative linking materials, process variables, and inspection results in plain language, as a production supervisor or surveyor would read it.

Mold Preparation and Stack Installation

Begin with a clean, structurally sound mold. Inspect for scratches or voids that could lock the part. Apply release agent per the manufacturer's system — paste wax, semi-permanent, or PVA — fully buffed and cured before any laminate touches the surface. Skipping or rushing release is the leading cause of part lockup.

Lay the reinforcement dry, following the instructor-provided laminate schedule. For this panel the schedule specifies biaxial fabric and woven roving over a structural core (PVC foam or balsa). Cut each ply precisely; overlapping biaxial layers at joints should meet the schedule's specified overlap width. Position the core, bevel or score the edges for resin flow if required. Install the infusion mesh or flow medium, spiral wrap feed line, and perimeter vacuum line, keeping feed and vacuum lines on opposite sides of the panel to ensure full cross-laminate flow.

Seal the bag, then pull vacuum. Hold the target vacuum level for a minimum 15 minutes with the pump isolated — watch the gauge for any rise. A passing integrity test shows less than the allowable pressure rise per your shop's standard (your instructor will state the acceptance criterion). Do not proceed to resin introduction until your instructor signs off on the vacuum test. This is the mandatory criterion; an infusion made without a passing test earns a zero regardless of part quality.

Safety Before You Mix

Vinyl ester resin with MEKP catalyst presents serious hazards.

• Eyes and skin: MEKP is a strong oxidizer and can cause permanent eye damage on contact. Wear chemical-splash goggles (not safety glasses) and nitrile gloves throughout mixing and infusion.
• Respiratory: Work in a ventilated space. Styrene vapor from vinyl ester exceeds permissible exposure limits quickly in enclosed areas. Wear a half-face respirator with organic-vapor cartridges rated for styrene.
• Fire: MEKP is reactive. Never add it to cobalt accelerator directly; always add MEKP to resin, never the reverse. Keep MEKP away from heat and combustibles. Have a dry-chemical extinguisher within reach.
• Trimming tools: Pneumatic cutters and oscillating saws produce glass-fiber dust. Wear hearing protection, safety glasses over goggles, and a dust mask (P100 minimum) when trimming. Vacuum rather than blow chips.
• Lockout/tagout: Before adjusting any vacuum pump or pneumatic line under load, follow your shop's LOTO procedure.

Resin Mixing and Batch Record

Weigh resin and catalyst on a calibrated digital scale. Record lot numbers for resin, catalyst, and every reinforcement ply on the batch record before you open containers. Calculate the gel time for your room temperature using the resin technical data sheet. Your resin introduction must be planned so that you expect to complete flow before 80 percent of pot life has elapsed — this is the gel-time utilization criterion. Record ambient temperature and relative humidity at mix time; vinyl ester systems are sensitive to both.

Infusion Execution

With vacuum confirmed and instructor sign-off in hand, submerge your feed line, release the clamp, and watch the resin front advance. Photograph the flow front at three intervals (early, mid-panel, near completion) and timestamp each photo in your process log. Monitor vacuum level throughout — any significant drop indicates a bag breach; clamp the feed line and locate the leak before resin travels further. When resin reaches the vacuum line, pinch the line closed and maintain vacuum through gel. Log the time resin flow stopped and the time gel was visually confirmed.

Post-Cure Inspection and Nonconformance Reporting

After full cure, trim the panel with appropriate tooling. Perform a visual inspection under good lighting using a 10× loupe: look for dry spots, air bubbles, resin-starved zones, delamination at the core bond line, and pinholes. Follow with a tap test — use a tap-test mallet or coin and listen for the hollow thud that indicates a void or delamination compared to the solid ring of a well-consolidated area. Mark any anomaly with a pencil circle and record its location, size, and character on the nonconformance report form. Even a perfect part gets a completed NCR form showing no findings — that is what a traceable record looks like.

Writing the Process Summary

Your one-page summary must cover: material lot numbers, process conditions (temperature, humidity, gel-time utilization), a brief narrative of infusion events, inspection results, and your NCR conclusions. Write it so someone who was not present could reproduce the critical decisions you made. That is the standard the industry — and both credential bodies — expect.