In this highly informative episode of MasterClass Season 2, Joshua Orchard delivers one of the deepest dives yet into the world of fiberglass and epoxy repairs—all demonstrated through real-time fixes on a Texan model aircraft. Whether you’re restoring a vintage warbird or reinforcing a modern sport plane, this session provides an expert breakdown of materials, techniques, pitfalls, and finishing strategies every builder should know.
Fiberglass 101: How Epoxy Really Works
Joshua opens by reminding viewers that fiberglassing is less intimidating than many builders think. In fact, he compares it to papier-mâché, with fabric replacing paper and epoxy replacing paste. The goal: ensure the cloth is fully saturated and bonded while avoiding heavy buildup that adds unnecessary weight.
When reinforcing repair areas or joining balsa blocks, having strong mounting hardware is equally important. Builders commonly rely on DU-BRO Socket Head Cap Screws for secure, vibration-resistant fastening:
Choosing the Right Epoxy & Cloth Weight
Z-Poxy Finishing Resin (Recommended)
Joshua stresses using thin finishing resin because it flows easily into the weave, cures evenly, and sands cleanly.
Avoid Polyester Resin
Hardware-store polyester resins cure hot, shrink, stink, and warp your model. They also risk delamination over time.
Cloth Selection Matters
Fiberglass cloth is sold by weight:
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6 oz fabrics provide structural strength
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0.6–1 oz fabrics are excellent finish layers
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Fine weave conform better to curves
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Multiple light layers often outperform one heavy layer
For clean cloth trimming, DU-BRO Scissors remain a workshop staple:\
Microballoons, Fillers & Perfecting the Finish
To fill dents, cracks, and low spots, Joshua demonstrates mixing microballoons into epoxy to create a sandable, lightweight filler. He also shows how Model Lite and automotive glazing putty help produce smooth surfaces for primer.
For guiding cables or servo leads through fiberglassed fuselages, builders turn to the Tube & Wire Holder for clean and secure routing:
Hands-On Wing Repair: Sand, Lay, Fill, Shape
Joshua repairs a damaged wing cover step-by-step:
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Sand the surface aggressively with 60-grit
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Lay wet fiberglass with finishing resin
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Fill creases with microballoon epoxy mix
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Trim excess cloth before it fully cures
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Sand to shape using coarse paper
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Apply spot putty to remove ridges
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Final sand with sponge-backed pads
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Inspect under angled light to reveal imperfections
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Finish with 0.6 oz cloth and Easy Coat before paint
For precision sanding and contouring, the DU-BRO Kwik Sand Hand Sanders
Crack Repairs on Cowls & Fiberglass Parts
Joshua demonstrates the textbook method for repairing cracked fiberglass cowls:
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Sand off all paint
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Drill a hole at the end of the crack
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Apply thin CA into the crack
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Reinforce the inside with fiberglass cloth
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Fill exterior with spackle or microballoons
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Sand and repaint
To mount cowls securely after repair, pilots trust DU-BRO Blind Nuts and machine screws for vibration-proof installation:
Safety, Mixing Ratios & Epoxy Wisdom
Key advice includes:
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Wear nitrile gloves and respirators
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Clean uncured epoxy with isopropyl alcohol
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Use denatured ethanol—not isopropyl—to thin epoxy (max 5%)
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Mix only small quantities to reduce premature curing
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Follow manufacturer mixing ratios strictly
Conclusion: Professional Repairs Start with the Right Materials
This MasterClass episode delivers a complete guide to fiberglass and epoxy repair—reinforcing both technique and the importance of safe, smart material choices. With the right resin, cloth weight, and DU-BRO hardware, builders can tackle structural restoration with confidence and achieve durable, smooth, paint-ready surfaces.
