Pro Marine Supplies vs Fiberglass Supply: Which Marine Epoxy Is Best for Boat Repair?
Last updated September 01, 2026 · Data from manufacturer TDS and market pricing
Summary
Pro Marine Supplies Deep Pour and Fiberglass Supply Epoxy 635 are both professional-grade epoxies suitable for marine repair, but they are optimized for different applications. Pro Marine Deep Pour is a low-viscosity (300 cps) casting epoxy with a 72-hour cure time, designed for deep pour applications like river tables and thick castings. Fiberglass Supply Epoxy 635 is a medium-viscosity (550 cps) laminating epoxy with an 18-hour cure time, specifically formulated for fiberglass wet-out, composite layup, and structural marine repair. For boat repair and composite construction, Fiberglass Supply Epoxy 635 is the better choice due to its faster cure, higher tensile strength, and optimized wet-out properties.
Comparison Table
| Property | Product A | Product B |
|---|---|---|
| Mix Ratio | 2:1 by volume | 3:1 by volume |
| Cure Time | 72 hours | 18 hours |
| Viscosity | 300 cps | 550 cps |
| Tensile Strength | 6,500 psi | 8,000 psi |
| Max Pour Depth | 2" per layer | ½" per layer |
| Coverage | 8 sq ft/gal | 15 sq ft/gal |
| Shore/Barcol Hardness | 80D Shore | 48-52 Barcol |
| Ideal Temperature | 75°F | 72°F |
Verdict
Choose Fiberglass Supply Epoxy 635 when you need a dedicated laminating epoxy for marine repair, fiberglass layup, and composite construction. Its faster cure (18 hours), higher tensile strength (8,000 psi), and optimized viscosity for cloth wet-out make it the professional choice for boat building and structural repairs. Choose Pro Marine Supplies Deep Pour when your project involves thick casting, encapsulation, or deep pour applications where the 2-inch pour depth and extended working time are beneficial. For marine repair specifically, Fiberglass Supply Epoxy 635 is the superior choice.
Frequently Asked Questions
Can Pro Marine Deep Pour be used for fiberglass layup?
Pro Marine Deep Pour is not optimized for fiberglass layup. Its low viscosity (300 cps) is designed for casting, not for wetting out fiberglass cloth. For proper fiberglass lamination, you need a medium-viscosity laminating epoxy like Fiberglass Supply Epoxy 635 (550 cps) that provides better cloth wet-out and less sag on vertical surfaces.
Is Fiberglass Supply Epoxy 635 suitable for below-waterline use?
Yes, Fiberglass Supply Epoxy 635 has excellent saltwater resistance per ASTM D1141 testing and is suitable for below-waterline applications. It is compatible with fiberglass, carbon fiber, and Kevlar reinforcements. For anti-fouling coating compatibility, allow the epoxy to fully cure before applying bottom paint.
Which epoxy has better working time for large repairs?
Pro Marine Deep Pour offers a longer working time (45-60 minutes at 75°F), which is beneficial for large casting projects. Fiberglass Supply Epoxy 635 has a more moderate working time (35-45 minutes at 72°F), which is standard for laminating work. For large surface laminations, the shorter working time is actually preferred to prevent sagging.
Can I use these epoxies for carbon fiber repair?
Fiberglass Supply Epoxy 635 is the better choice for carbon fiber repair due to its higher tensile strength (8,000 psi) and optimized wet-out properties. Carbon fiber repairs require a laminating epoxy that can properly wet out the fibers and achieve maximum structural bond. Pro Marine Deep Pour's casting formulation is not ideal for structural carbon fiber repairs.
→ View Pro Marine Supplies Deep Pour Epoxy · → View Fiberglass Supply Epoxy 635