Benefits
Heavy-Duty Foil Protection
The 5 mil aluminum foil backing provides greater foil thickness than many standard aluminum foil tapes, making 438 suitable when a heavier-duty foil barrier or protective layer is required.
Heat Shielding and Heat Reflection
The aluminum foil provides a reflective surface for heat and light. Its thermal conductivity also allows heat to dissipate across the tape surface, which can help reduce localized hot spots in selected applications.
Moisture Barrier
3M specifies a low water-vapor transmission rate of 0.77 g/m²/24 h, supporting moisture-barrier, seaming and sealing applications.
Long-Term Environmental Durability
The combination of aluminum foil and acrylic adhesive is designed to provide long-term performance when exposed to moisture, weathering, UV and solvents in suitable applications.
Conformable Dead-Soft Foil
The dead-soft aluminum backing can conform to irregular surfaces and is suitable for applications where the foil needs to follow a component’s geometry.
Flame-Resistance Performance
3M 438 is UL Recognized to UL 746C and Classified by UL to UL 723, Class L for low flammability. The product also meets FAR 25.853(a) requirements.
Technical Specifications
| Property | 3M™ Heavy Duty Aluminum Foil Tape 438 |
|---|---|
| Product type | General Purpose Aluminum Foil Tape |
| Backing material | Aluminum foil |
| Adhesive type | Acrylic |
| Color | Shiny silver |
| Backing thickness | 0.13 mm (5 mil) |
| Total tape thickness | 0.18 mm (7.2 mil) |
| 180° peel adhesion to steel | 4.7 N/cm (43 oz/in) at 23°C |
| Tensile strength | 103 N/cm (59 lb/in) |
| Elongation at break | 10% |
| Water vapor transmission | 0.77 g/m²/24 h |
| Minimum long-term temperature resistance | -54°C (-65°F) |
| Long-term temperature resistance | 149°C (300°F) |
| UL classification | UL 746C / UL 723 Class L |
| Aerospace flammability | FAR 25.853(a), applicable requirements |
| Standard roll length | 55 m (60 yd) |
3M identifies these values as representative or typical data, not specification limits. The latest technical data sheet should be used for final product qualification.
Applications
Heat Shielding of Delicate Parts
3M 438 is designed for heat shielding applications where a robust aluminum foil backing is required to protect sensitive components from heat exposure.
Heat Reflection
The shiny aluminum surface reflects radiant heat and light, making the tape suitable for selected thermal-management applications.
Moisture Barrier
The aluminum foil construction can provide a barrier against moisture and water vapor in suitable sealing applications.
Seaming and Sealing
The tape can be used for selected:
- Seaming
- Joint sealing
- Surface patching
- Barrier applications
Refrigerator and Freezer Coil Attachment
3M lists refrigerator and freezer coil attachment among the recommended applications for 438.
Plastic Protection
The tape can be used to protect selected plastic surfaces from heat and UV exposure.
Appliance Applications
3M also identifies 438 for applications in the appliance industry, including use as a barrier, protector and thermal conductor. The product can also be used where a 5 mil aluminum foil barrier is required for vinyl-coated wires in certain appliance applications.
Aircraft and Truck Trailer Repair
The technical data sheet identifies patching tears in aircraft and truck-trailer skins as an application example.
Compatible Materials
3M™ Heavy Duty Aluminum Foil Tape 438 may be evaluated for use on:
- Aluminum
- Steel
- Other metal surfaces
- Selected plastics
- Appliance components
- Vinyl-coated wire applications
- Foil and barrier materials
- Selected insulation and thermal-management materials
Actual adhesion depends on surface condition, material formulation and application environment. For painted, coated or treated substrates, application testing is recommended.
Industries
3M™ Heavy Duty Aluminum Foil Tape 438 may be relevant to:
- Aerospace
- Appliance Manufacturing
- HVAC and Refrigeration
- Automotive
- Construction
- Industrial Manufacturing
- Metal Processing
- Electrical and Electronics
- Maintenance & Repair
- Thermal Management
Its aerospace relevance is supported by its published FAR 25.853(a) compliance, while the product data sheet also specifically identifies appliance and aircraft/trailer applications.
Why Choose 3M™ Heavy Duty Aluminum Foil Tape 438?
3M™ 438 is differentiated by its 5 mil dead-soft aluminum foil backing, which provides a heavier foil construction than thinner products in the 3M aluminum foil tape family.
Its combination of:
- Heavy-duty foil backing
- Acrylic adhesive
- Heat and light reflection
- Thermal conductivity
- Moisture-barrier capability
- UV and weathering resistance
- Flame-resistance performance
makes it suitable for demanding industrial sealing, shielding and protection applications.
For customers requiring customized dimensions, Yousan can evaluate slitting, rewinding, laminating and precision converting according to the specific tape configuration and production requirements.
Installation Guide
1. Prepare the Surface
Clean the application surface and remove dust, oil, grease and other contaminants.
2. Check the Application Temperature
The tape should be applied to a clean, dry surface under conditions appropriate for the adhesive and substrate. For critical applications, follow the latest 3M application recommendations.
3. Cut the Required Length
Measure and cut the required tape length while avoiding unnecessary deformation of the aluminum backing.
4. Position the Tape
Align the tape over the seam, joint, shielding area or target component.
5. Apply Firm Pressure
Press the tape evenly against the substrate to maximize adhesive contact and minimize air entrapment.
6. Inspect the Application
Check for wrinkles, lifted edges or gaps, particularly when the tape is being used as a moisture barrier or heat-shielding layer.
For critical aerospace, electrical or thermal applications, validate the complete assembly under the intended operating conditions.
Storage
Store 3M™ Heavy Duty Aluminum Foil Tape 438 in its original packaging under the recommended conditions:
- Temperature: 16–27°C (60–80°F)
- Relative humidity: 40–60% RH
- Keep away from direct sunlight
- Store in a clean and dry area
3M recommends using the product within 24 months from the date of manufacture for best performance when stored under these conditions.
FAQ
What is 3M™ Aluminum Foil Tape 438?
3M™ Heavy Duty Aluminum Foil Tape 438 is a heavy-duty aluminum foil tape with a 0.13 mm dead-soft aluminum foil backing and acrylic adhesive, designed for heat shielding, heat reflection, moisture-barrier, seaming and sealing applications.
What is the thickness of 3M 438?
The aluminum foil backing is approximately 0.13 mm (5 mil), while the total tape thickness is approximately 0.18 mm (7.2 mil).
What adhesive does 3M 438 use?
3M 438 uses a transparent acrylic pressure-sensitive adhesive.
Is 3M 438 a heavy-duty aluminum foil tape?
Yes. 3M specifically names it 3M™ Heavy Duty Aluminum Foil Tape 438 and describes it as suitable where a heavier-weight foil is required.
What temperature can 3M 438 withstand?
The published long-term temperature range is approximately -54°C to 149°C (-65°F to 300°F). The technical data sheet notes that higher temperatures can be tolerated for shorter periods, depending on conditions.
Is 3M 438 suitable for heat shielding?
Yes. Heat shielding of delicate parts is one of 3M’s recommended applications.
Is 3M 438 suitable for heat reflection?
Yes. The aluminum foil provides a reflective surface for heat and light.
Can 3M 438 be used as a moisture barrier?
Yes. 3M specifically lists moisture barrier applications and publishes a water vapor transmission value of 0.77 g/m²/24 h.
Is 3M 438 suitable for refrigerator and freezer coils?
Yes. Refrigerator and freezer coil attachment is a recommended application.
Is 3M 438 suitable for aerospace applications?
3M’s technical documentation states that the product meets FAR 25.853(a) requirements. It should still be evaluated against the complete aerospace application specification before qualification.
Does 3M 438 have UL certification?
3M states that 438 is UL Recognized to UL 746C and Classified by UL to UL 723, Class L for low flammability.
What is the difference between 3M 438 and 3M 431?
The main difference is the foil construction. 3M 438 has a 0.13 mm (5 mil) aluminum foil backing and 0.18 mm total thickness, while 3M 431 has a thinner 0.05 mm foil backing and 0.08 mm total thickness. 438 is therefore the heavier-duty option in terms of foil thickness.
What is the difference between 3M 438 and 3M 427?
Both are aluminum foil tapes with acrylic adhesive, but 3M 438 uses a much heavier 5 mil aluminum foil backing, whereas 427 uses a thinner foil construction and an easy-release liner. The choice depends on whether the application prioritizes heavier foil protection or linered converting.
Can 3M 438 be used for die-cutting?
The tape can be evaluated for converting and die-cutting based on the required design and process. For applications specifically requiring a linered foil tape for precision die-cutting, a linered product such as 3M 427 may also be evaluated.
Downloads
Available upon request:
- 3M 438 Aluminum Foil Tape Technical Data Sheet (TDS)
- Safety Data Sheet (SDS)
- Product Brochure
- Die-Cutting Capability Guide
Please contact our sales team if you require the latest technical documentation.
