Alkali‑Free Fiberglass Filter Mesh for Molten Aluminum

1. Product Overview

Alkali-free fiberglass filter mesh is a professional disposable high-temperature filtering material specially developed for molten aluminum and aluminum alloy casting industries.

It is widely used in gravity die casting, low-pressure die casting, high-pressure die casting, sand casting, and investment casting of aluminum products.

Effectively removes oxide inclusions, floating dross, slag particles, and non-metallic impurities inside molten aluminum, stabilizes molten metal flow, eliminates casting turbulence, and significantly improves the yield and mechanical performance of finished aluminum castings.

It is the most cost-effective primary filtration solution in the aluminum foundry industry worldwide.

2. Core Material & Chemical Physical Properties

The filter mesh is woven from high-purity E-grade alkali-free fiberglass yarn, a highly stable fiber material specially formulated for non-ferrous metal casting.

E-glass features an extremely low alkali content (<0.8%), high silica content and outstanding chemical stability, and remains fully inert when exposed to high-temperature molten aluminum.

It will not dissolve, decompose or leach ions upon contact with hot molten aluminum, so no secondary impurity contamination will occur.

The material's continuous working temperature ranges from 700℃ to 820℃, with a softening point above 900℃ and a melting point over 1100℃.

It perfectly matches the conventional aluminum pouring temperature range of 680℃–780℃, ensuring no fiber breakage, no mesh collapse, no shedding, and no deformation during the entire casting process.

3. Weaving Structure & Advanced Production Technology

The mesh adopts a professional leno weave (lock-stitch) structure, different from ordinary plain weave fabric.

Leno weave tightly interlocks every fiber intersection point, forming a fixed three-dimensional mesh structure.

Even under the instantaneous impact and high-speed scouring of flowing molten aluminum, the mesh aperture remains uniform without offset, expansion, fiber loosening or dropping.

After weaving, the base fabric undergoes high-temperature desizing, professional phenolic resin impregnation, high-temperature curing, and surface refractory treatment.

The entire production process removes residual wax, organic matter, and gas-producing components, achieving low gas evolution and high-temperature resistance.

Two finished versions are available: standard resin-coated type and high-grade smokeless carbonized type.

4. Filtration Mechanism (Double Physical Purification Principle)

4.1 Impurity Interception

The uniform mesh aperture physically traps large and medium-sized impurities in molten aluminum, including alumina film, oxidized dross, refractory particles, mold sand, and non-metallic inclusions, preventing slag holes and inclusions inside castings.

4.2 Flow Straightening & Turbulence

EliminationMolten aluminum usually produces severe turbulence, splashing, and vortex entrapment during pouring.

The dense three-dimensional fiber network disperses chaotic liquid flow, stabilizes flow speed, eliminates vortexes, and reduces air entrapment.

This greatly reduces porosity, pinholes, and oxidation secondary pollution.

5. Two Product Grades & Application Differences

Grade 1: Standard Resin-Coated Type Cost-effective, general low-gas formula, suitable for ordinary aluminum castings, aluminum ingots, aluminum bars, and common die-cast parts. Stable performance, no fiber shedding, meets most conventional casting requirements.

Grade 2: Smokeless Carbonized High-End TypeSecondary high-temperature carbonization treatment removes all organic volatile substances. Ultra-low gas emission, no smoke during pouring, no bubble defects.

Specially used for high-precision aluminum parts such as automotive wheel hubs, automotive structural parts, aerospace aluminum parts, and high-end mechanical castings.

6. Complete Technical Specifications

● Material: E-grade alkali-free fiberglass

● Weaving Method: Leno lock-stitch weave

● Continuous Temperature Resistance: 700–820℃

● Softening Point: ≥900℃

● Thickness: 0.18–0.35mm

● Mesh Aperture: 1.0mm / 1.2mm / 1.5mm / 2.0mm / 2.5mm

● Fabric Weight: 150–350g/㎡

● Thickness: 0.18–0.35mm

● Shape Options: Round sheet, square sheet, custom cap/hat type thermoformed filter

● Gas Evolution: ≤0.2% (carbonized type)

● Feature: Tear-resistant, anti-scouring, no shedding, no reaction with aluminum

7. Industrial Application Scope

Widely applied in aluminum alloy wheel hubs, automobile aluminum parts, new energy vehicle structural parts, aluminum alloy die castings, aluminum ingots, aluminum rods, aluminum plates, hydraulic parts, pneumatic parts, mechanical equipment aluminum castings, aerospace aluminum accessories, and precision military aluminum castings. Suitable for all aluminum gravity casting, low-pressure casting and die-casting production lines.

8. Core Advantages 

✅Zero Pollution: Completely inert to molten aluminum, no chemical reaction, no secondary contamination.

✅High Temperature Stability: No breaking, collapsing or fiber dropping under high-temperature aluminum scouring.

✅Excellent Flow Control: Effectively eliminates casting turbulence and reduces air entrapment defects.

✅Ultra-Low Gas Emission: Carbonized version achieves smokeless pouring, suitable for high-end precision casting.

✅Cost-Effective: Much lower cost than ceramic foam filters, easy installation, suitable for large-scale mass production.

✅Recyclable Residue: After cooling, the mesh floats on dross, and residual aluminum can be directly remelted without separation.

✅Customization Support: Any size, shape, aperture and thickness can be customized according to customer molds.

FAQ

1: What is the Max. working temperature of this filter mesh for molten aluminum?

It works continuously at 700–800°C, with a softening point up to 900°C. This range perfectly matches standard pouring temperatures for aluminum alloys.

2: Will this fiberglass mesh react with molten aluminum?

It will not. Made from low-alkali E-glass, it has excellent chemical inertness. It does not react with molten aluminum or introduce impurities that alter alloy composition.

3: What weave pattern do you use?

Leno weave. This design locks fiber intersections tightly, preventing mesh shift and fiber shedding when exposed to fast-flowing molten aluminum.

4: What product variants are available?

We offer two main options: standard resin-impregnated grade and smokeless carbonized grade. The carbonized grade features low gas emissions, ideal for high-precision aluminum castings such as automotive wheel hubs.

5: Can shapes and sizes be custom-made?

Yes. We supply flat round or square sheets, plus thermoformed cap-style filters based on customer gating system drawings.

6: What is the difference between fiberglass mesh and ceramic foam filters for aluminum filtration?

● Fiberglass mesh is commonly used for primary filtration in sprue cups or runners. It is low-cost and simple to install.

●Ceramic foam filters are used for secondary fine filtration to capture tiny inclusions.

●The two products can be used together in one casting setup.

7: Can leftover aluminum with the filter mesh go straight back into the melting furnace?

Yes. After cooling, the fiberglass mesh floats on top of aluminum dross. The aluminum scrap can be remelted directly with no complicated separation required.