Description
Alustep 500 SL Fiberglass Skin Aluminum Honeycomb Panel
Alustep 500 SL is a sandwich panel built from an aluminum honeycomb core bonded between two bidirectional glassfiber skins impregnated with epoxy resin. The fiberglass skin gives it a lower coefficient of thermal expansion than an aluminum-faced panel, which is why it’s the panel we point fabricators to when stone or porcelain is being laminated to it and the finished assembly goes outdoors. Chemical Concepts stocks Alustep 500 SL in 5 ft x 10 ft sheets in four thicknesses. Custom sizes, thicknesses, cell sizes, and core densities are built to order.
Stocked Panels
All stocked panels use 490 g/m² glassfiber epoxy skins over a 1/4 in (6 mm) hexagonal aluminum honeycomb core, supplied unsquared.
| Panel Size | Panel Thickness | Cell Size | Weight | Sheet Weight | SKU |
|---|---|---|---|---|---|
| 5 ft x 10 ft | 1/4 in (6.4 mm) | 1/4 in (6 mm) | 0.41 lb/ft² | 20 lb (9.3 kg) | CEL-AS-500-SL-06-05X10-2-0640 |
| 5 ft x 10 ft | 1/2 in (12.7 mm) | 1/4 in (6 mm) | 0.48 lb/ft² | 24 lb (10.9 kg) | CEL-AS-500-SL-06-05X10-2-1270 |
| 5 ft x 10 ft | 3/4 in (19 mm) | 1/4 in (6 mm) | 0.55 lb/ft² | 28 lb (12.5 kg) | CEL-AS-500-SL-06-05X10-2-1900 |
| 5 ft x 10 ft | 1 in (25 mm) | 1/4 in (6 mm) | 0.63 lb/ft² | 32 lb (14.1 kg) | CEL-AS-500-SL-06-05X10-2-2540 |
Panel Construction
A: Glassfiber skins
B: Epoxy resin adhesive
C: Aluminum honeycomb core
|
Technical Characteristics
| Construction | Aluminum honeycomb core, glassfiber epoxy skins both faces |
| Skin material | Bidirectional glassfiber fabric, 490 g/m², epoxy impregnated |
| Core material | Aluminum alloy 3003 / 3005 / 3103 / 3104, hexagonal cell |
| Core adhesive | Epoxy resin |
| Stocked cell size | 1/4 in (6 mm). 3/8 in available on request |
| Stocked panel thicknesses | 1/4 in (6.4 mm), 1/2 in (12.7 mm), 3/4 in (19 mm), 1 in (25 mm) |
| Stocked panel size | 5 ft x 10 ft, unsquared |
| Thickness tolerance | ±0.3 mm (±0.012 in) |
| Dimension tolerance | ±30 mm (±1.18 in) |
| Skin elastic modulus (E) | 26,000 ±2,000 MPa (3.8 x 106 psi) |
| Compressive stabilized strength | 2.9 ±0.3 MPa (421 psi), ASTM C365-365M |
| Peel resistance | > 500 N / 76 mm, or > 55 Nmm/mm, ASTM D1781-98 |
| Maximum service temperature | -50 to +90 °C (-58 to +194 °F) |
| Thermal expansion coefficient | 1.5 x 10⁻⁵ per °C, or 1.5 mm per meter over a 100 °C change |
| Manufacturer panel sizes | 1250 x 2500 mm and 1500 x 3000 mm standard, up to 1550 x 3050 mm on request |
| Manufacturer thickness range | 5 mm to 50 mm |
Panel Performance Data
The values below are published by CEL for panels built on a 1/4 in (6 mm) 56 kg/m³ honeycomb core with epoxy adhesive, which is the core used in our stocked panels.
| Property | Test Method | 5 mm | 10 mm | 15 mm | 20 mm | 25 mm | 30 mm | 35 mm |
|---|---|---|---|---|---|---|---|---|
| Panel weight | 1.9 kg/m² | 2.2 kg/m² | 2.5 kg/m² | 2.8 kg/m² | 3.1 kg/m² | 3.3 kg/m² | 3.5 kg/m² | |
| Maximum load | ASTM C393 | 130 N 29 lbf |
270 N 61 lbf |
420 N 94 lbf |
570 N 128 lbf |
720 N 162 lbf |
850 N 191 lbf |
1,000 N 225 lbf |
| Deflection at maximum load | ASTM C393 | 42 ±6 mm | 20 ±3 mm | 14 ±2 mm | 11 ±2 mm | 8 ±1 mm | 7 ±1 mm | 6 ±1 mm |
| Moment of inertia (I) | 4,200 mm⁴/m | 18,400 mm⁴/m | 42,600 mm⁴/m | 76,800 mm⁴/m | 121,000 mm⁴/m | 175,400 mm⁴/m | 239,940 mm⁴/m |
Panel weight carries a tolerance of ±0.2 kg/m². ASTM C393 testing uses a 540 x 540 mm sample on four support points with 500 mm between the lower points. Physical and mechanical properties are provided as a basis for comparison. Verify performance against your specific application requirements before design use.
Honeycomb Core Properties by Cell Size
| Cell Diameter | Foil Thickness | Core Density | Compressive Stabilized Strength |
|---|---|---|---|
| 1/4 in (6 mm) | 50 micron | 56 to 59 kg/m³ (3.5 to 3.7 lb/ft³) | 3.0 to 3.5 MPa (435 to 508 psi) |
| 1/4 in (6 mm) | 70 micron | 80 to 83 kg/m³ (5.0 to 5.2 lb/ft³) | 4.3 to 4.6 MPa (624 to 667 psi) |
| 3/8 in (9 mm) | 50 micron | 39 to 40 kg/m³ (2.4 to 2.5 lb/ft³) | 1.4 to 1.95 MPa (203 to 283 psi) |
| 3/8 in (9 mm) | 70 micron | 54 kg/m³ (3.4 lb/ft³) | 2.5 to 2.6 MPa (363 to 377 psi) |
Performance in Production
- At 0.41 to 0.63 lb/ft², Alustep 500 SL weighs roughly half what an aluminum-skinned panel of the same thickness weighs. A full 5 ft x 10 ft sheet runs 20 to 32 lb, which one person can move.
- Thermal expansion of 1.5 x 10⁻⁵ per °C is lower than an aluminum-faced panel. When stone or porcelain is bonded to the panel and the assembly sees a temperature swing, the panel and the stone move at closer to the same rate, which puts less shear into the laminating adhesive over the life of the installation.
- Service range of -50 to +90 °C is wider than the aluminum-skinned alternative on both ends, which matters on exterior work through a full seasonal cycle.
- The raw glassfiber skin takes epoxy laminating adhesives directly. No primer or mechanical abrasion step is needed the way it can be on a coated or anodized aluminum skin.
- Peel resistance is greater than 500 N per 76 mm, which is the skin to core bond holding under the stresses laminating puts into the panel.
- Cell size and foil thickness drive core density and compressive strength. The stocked 1/4 in cell carries higher compressive strength than a 3/8 in cell core, which matters where threaded inserts, fasteners, or point loads bear on the core.
Choosing Between Alustep 500 SL and Compocel AL
We stock both. They solve different problems.
| Alustep 500 SL | Compocel AL | |
|---|---|---|
| Skins | Glassfiber epoxy, 490 g/m² | Aluminum, 0.8 mm |
| Weight, 1 in panel | 0.63 lb/ft² | 1.31 lb/ft² |
| Thermal expansion | 1.5 x 10⁻⁵ per °C | 2.3 x 10⁻⁵ per °C |
| Service temperature | -50 to +90 °C | -40 to +60 °C |
| Skin elastic modulus | 26,000 MPa | 68,000 to 70,000 MPa |
| Stocked sizes | 5 ft x 10 ft | 5 ft x 10 ft, 4 ft x 10 ft, 4 ft x 8 ft |
| Stocked cell size | 1/4 in | 3/8 in, plus one 1/2 in |
Alustep 500 SL is the one to reach for when material is being laminated to the panel and the finished assembly goes outdoors. The lower thermal expansion keeps the panel and the bonded stone moving closer together through a temperature cycle, and the epoxy glassfiber skin bonds without surface preparation.
Compocel AL has a stiffer skin, so it carries more load at a given thickness, and it’s available in more sheet sizes. It’s the usual choice for interior work, though it is not limited to interior use. Call us if the application sits somewhere between the two and we’ll work through it with you.
Common Applications
- Backing and reinforcement for natural stone, marble, semi-precious stone, mosaic, and porcelain slabs
- Exterior stone cladding and ventilated facade panels
- Stone countertops, waterfall ends, and vanity tops where weight is reduced by halving slab thickness
- Marine interiors, furniture, and flooring
- Interior partitions, wall panels, and door skins
- Lightweight panels where a non-conductive skin is preferred
Tested to American Standards
CEL reports that Alustep 500 SL has been tested to the following standards. Contact us for test reports if your specification requires documented results.
| Standard | Property |
|---|---|
| ASTM C67-M18 | Water absorption |
| ASTM E72-15 | Strength, transverse load |
| ASTM C297 M-16 | Flatwise tensile strength |
| ASTM E84-17 | Flame spread |
| TAS 201 and TAS 203 | Impact and cyclic wind pressure |
Fabrication and Processing
Alustep 500 SL is cut, milled, drilled, and shaped with standard CNC equipment. CEL also performs cutting to size, cutting to shape, edging, and insert installation to customer drawings.
- Cutting to size, milling, drilling, and cutting to shape
- Panel edging and insert installation
- Threaded inserts set into the honeycomb core for mechanical attachment
Custom Panel Configurations
| Variable | Documented Range |
|---|---|
| Panel size | Up to 1550 x 3050 mm |
| Panel thickness | 5 mm to 50 mm |
| Core cell diameter | 3 mm to 19 mm |
| Core foil thickness | 50 or 70 micron |
| Core density | 20 to 116 kg/m³ (1.2 to 7.2 lb/ft³) |
Need panel data for a specific application? Send us the SKU along with your span, load, and support condition and we will get you the panel data from CEL. For custom sizes, thicknesses, cell diameters, or core densities, tell us the target specification and we will confirm feasibility before quoting.
Shipping and Freight
Alustep 500 SL panels are oversize and ship on custom-built pallets, so freight cannot be calculated at checkout. Place your order as normal and our team will contact you with a freight quote before anything ships. No freight is charged and no panels move until you approve the quote.
Local pickup is available if you would rather collect the panels yourself. Select pickup at checkout or contact us to arrange a time.
Frequently Asked Questions
What sizes and thicknesses of fiberglass honeycomb panel are in stock?
Chemical Concepts stocks Alustep 500 SL in 5 ft x 10 ft sheets in 1/4 in, 1/2 in, 3/4 in, and 1 in thickness, all on a 1/4 in cell aluminum honeycomb core. Other sizes, thicknesses, and cell sizes are built to order.
Why choose a fiberglass skin panel over an aluminum skin panel for stone?
Thermal expansion. Alustep 500 SL expands at 1.5 x 10⁻⁵ per °C against 2.3 x 10⁻⁵ per °C for an aluminum-faced panel. With stone bonded to the panel, the closer the two materials track each other through a temperature change, the less shear ends up in the laminating adhesive. That matters most on exterior work that cycles through a full year of temperature swings.
How much does a panel weigh?
Alustep 500 SL runs 0.41 to 0.63 lb/ft² depending on thickness. A 5 ft x 10 ft sheet is about 20 lb at 1/4 in and 32 lb at 1 in, which is roughly half the weight of an aluminum-skinned panel of the same thickness.
Can Alustep 500 SL be used outdoors?
Yes. The service range is -50 to +90 °C (-58 to +194 °F), and CEL reports testing to ASTM C67-M18 for water absorption and TAS 201 and 203 for impact and cyclic wind pressure. Contact us for test reports if your specification requires documented results.
What adhesive bonds stone to Alustep 500 SL?
The raw glassfiber skin takes epoxy laminating adhesives directly, with no primer or abrasion step required. Chemical Concepts supplies laminating epoxies and honeycomb bonding systems selected for stone, porcelain, and laminate lamination onto honeycomb panels.
What is the honeycomb cell size?
1/4 in (6 mm) hexagonal cell on all stocked panels. 3/8 in cell is available on request. The 1/4 in cell carries higher core compressive strength, which matters where inserts, fasteners, or point loads bear on the core.
Can Alustep 500 SL be cut to size?
Yes. It is cut, milled, drilled, and shaped with standard CNC equipment. CEL also performs cutting to size, cutting to shape, edging, and insert installation to customer drawings. Contact us for panels processed before shipment.
How do you fasten fiberglass skin honeycomb panels?
Threaded inserts and deform nuts set into the honeycomb core are the usual method. Chemical Concepts stocks inserts made for honeycomb sandwich panels.
Related Products
- Honeycomb panel bonding systems and laminating epoxies
- Honeycomb sandwich panel threaded inserts and deform nuts
- Compocel AL aluminum skin honeycomb sandwich panel
- Clear-Step translucent sandwich panel for backlit stone
See the Alustep 500 SL technical data sheet for complete manufacturer specifications.












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