Key Points For Selecting Fiberglass Cloth And Fiberglass Mat
Basic Material Analysis:
1. Alkali-free fiberglass mat, also known as alkali-free chopped strand mat, is manufactured by cutting fiberglass yarn into fixed-length fibers. These fibers are then randomly laid out on a conveyor belt using a settling device, bonded and cured with powder or emulsion binders, and finally dried, cooled, and wound. Common specifications for fiberglass fishing boats include:
EMC300-1040 (300g/㎡, 1040mm width)
EMC450-1040 (450g/㎡, 1040mm width)
EMC600-1040 (600g/㎡, 1040mm width)
2. Fiberglass cloth, also known as untwisted fiberglass roving, is made by interlacing untwisted rovings in the warp and weft directions according to a specific pattern. When woven using continuous single-strand untwisted fiberglass roving (direct yarn), the resulting woven fabric is untwisted roving cloth, commonly known as checkered cloth. Common specifications for fishing boat manufacturing are:
EWR400-1040 (400g/㎡, 1000mm width)
EWR600-1040 (600g/㎡, 1000mm width)
EWR800-1040 (800g/㎡, 1000mm width)
These two types of materials seem simple, but there are actually many intricacies. We will analyze them from three key dimensions:
一. Glass Fiber Composition
According to the "Specifications for the Construction of Fiber Reinforced Plastics for Fishing Boats," fiberglass boat manufacturing must use alkali-free glass fiber (sodium oxide content <0.8%). Medium-alkali products have poor corrosion resistance and are prone to alkali precipitation after prolonged immersion in water [leading to embrittlement of the laminates], and are strictly prohibited from use in hull construction.
二. Manufacturing Process System Currently
The mainstream production processes are divided into two major systems: tank furnace drawing (accounting for over 95%) and crucible drawing.
• Tank furnace drawing: Utilizes platinum spindles for direct drawing, achieving continuous production from raw material melting to drawing. It boasts advantages such as high capacity (up to 100,000 tons per kiln per year), low energy consumption (more energy-efficient than crucible processes), and stable quality (yarn tex value fluctuation < ±3%).
• Crucible drawing: A secondary melting process, it suffers from high energy consumption and poor product consistency, and is now largely obsolete.
三. Manufacturer Tier System Domestic
Manufacturers exhibit a clear tiered distribution, forming a "one superpower and two strong players" pattern: China Jushi (27% global market share), Taishan Fiberglass, and Chongqing International, the three giants, collectively control approximately 45% of global production capacity.
Currently, the alkali-free fiberglass roving and alkali-free chopped strand mat supplied to the domestic market mainly come from the following three types of factories:
1. Reputable furnace manufacturers that produce their own reinforcing materials (cloth/mat), employing standardized production management systems. Their products are certified by classification societies such as DNV-GL and CCS. Products from the "One Super and Two Strong" factories, in particular, are of stable and guaranteed quality, and can be purchased with confidence!
2. Large and medium-sized fiberglass woven fabric processing plants with certain technical capabilities. These factories often purchase raw materials from furnace manufacturers for secondary processing. Although product stability may fluctuate due to different raw material sources, the quality of genuine raw materials is generally guaranteed. [It is recommended to focus on the stability of their raw material procurement and their process control capabilities].
3. Small and micro-sized processing plants with varying technical levels. To reduce costs, they often mix and use second-grade/defective raw materials from furnace manufacturers. [Some even illegally add recycled waste fibers or medium-to-high alkali raw materials]. Such "blended" products are prone to uneven impregnation and fluctuations in tensile strength, directly affecting the interlayer shear strength and fatigue resistance of fiberglass fishing boats. Experimental data shows that the strength reduction rate of key parts of a ship's hull using inferior materials can be 3-5 times that of genuine products.
In the chaotic market of alkali-free fiberglass, batches of nearly identical products are displayed in front of factories, yet their prices vary drastically. Those inferior materials, deliberately driven down to lower costs, are like wolves in sheep's clothing, deceiving buyers with their near-perfect appearance. Some fiberglass fishing boat factory buyers, tempted by low prices, hastily sign orders, unaware that the flimsy raw material invoices in their hands are quietly transforming into fatal cracks in the future hull.
When these substandard fiberglass materials are introduced into the production line, the hidden dangers are buried deep like seeds. The bond between resin and fiber weakens, and bubbles sprout like anthills before a dam bursts. Within the seemingly smooth hull laminate, uneven fiber impregnation patches are like hidden ailments, tearing apart the fragile bond with every wave's impact. Interlaminar shear strength is lost imperceptibly, and fatigue resistance becomes like a hollowed-out beam – the seemingly pristine fishing boat is actually a hidden danger counting down the days to come.
When boat owners stroke the brand-new hull, their fingertips trace the perfectly smooth coating, unable to touch the underlying stress groans. Until one day, an unexpected surge of water suddenly tears open the cracks, and the structural strength once devoured by cheap materials will ultimately become a blood-and-tears exclamation mark in the logbook.
