3M 425 Alternative — Polyken 345SW Premium Self-Wound Foil Tape
Direct specification comparison for 3-mil aluminum foil tape — aircraft masking, vapor barriers, heat shielding, and HVAC sealing
Polyken 345SW
Berry Global — Franklin, MA
Premium self-wound foil tape with heavy-duty dead soft aluminum backing and acrylic adhesive — no release liner. 68 oz/in adhesion to steel — roughly 45% above 3M 425's published 47 oz/in. Carries AMS-T-23397B, MIL-T-23397, L-T-80B, and Gulfstream GAMPS 4002 / GAT100BC approvals for aircraft sealing, masking, heat shielding, and vapor barrier applications.
3M #425
3M Company — St. Paul, MN
Industry-standard 3-mil aluminum foil tape with transparent acrylic adhesive, widely used in HVAC, aerospace masking, heat reflection, and sealing. Documented low moisture vapor transmission and UL 746C / UL 723 Class "L" listings. Available through virtually every industrial distributor.
Overall comparison score
Full specifications comparison
| Property | Polyken 345SW | 3M #425 | Advantage |
|---|---|---|---|
| Construction | |||
| Foil thickness | 3.0 mil dead soft aluminum | 2.8 mil dead soft aluminum (nominal 3 mil) | Tie |
| Total tape thickness | 5.0 mil (0.127 mm) | 4.6 mil (0.12 mm) | Polyken |
| Adhesive type | Acrylic | Transparent acrylic | Tie |
| Liner | None — self-wound (no liner waste) | None — self-wound | Tie |
| Physical Properties | |||
| Adhesion to steel | 68 oz/in (7.44 N/cm) | 47 oz/in (5.1 N/cm) | +45% stronger |
| Tensile strength | 26 lb/in (45.53 N/cm) | 28 lb/in (49 N/cm) | 3M #425 |
| Elongation | 3% | 6% | 3M (more conformable) |
| High temp resistance | 350°F (177°C) | 300°F (149°C) long-term | Polyken |
| Low temp resistance | −40°F (−40°C) | −65°F (−54°C) | 3M (colder) |
| Water vapor transmission | Not published | 0.77 g/m²/24h (documented) | 3M (documented) |
| Packaging & Value | |||
| Standard roll length | 60 yd (stocked in 1" & 2" widths) | 55 m (60 yd) | Tie |
| Shelf life | 24 months | 24 months | Tie |
| Availability | Stocked / available globally | In stock nationwide | Tie |
| Compliance | |||
| FAR 25.853(a) flammability | Yes | Yes | Tie |
| Aerospace / military specs | AMS-T-23397B, MIL-T-23397, L-T-80B, Gulfstream GAMPS 4002 / GAT100BC | L-T-80C (can be certified), UL 746C, UL 723 Class "L" | Polyken (broader aero) |
Specifications & approvals
Where each product wins
- Adhesion to steel ~45% higher — 68 vs. 47 oz/in
- Higher heat rating: 350°F vs. 300°F long-term for 3M 425
- Thicker total tape: 5.0 mil vs. 4.6 mil
- Broader aerospace coverage: AMS-T-23397B, MIL-T-23397, Gulfstream GAMPS 4002 / GAT100BC
- Self-wound construction — no liner waste
- Excellent solvent resistance for paint stripping & electroplating masking
- Wider cold temperature range — rated to −65°F vs. −40°F for Polyken
- Slightly higher tensile strength: 28 vs. 26 lb/in
- Higher elongation (6% vs. 3%) for better conformability over contours
- Documented low moisture vapor transmission rate as a sealant
- UL 746C and explicit UL 723 Class "L" file listings
Which tape to specify
| If your requirement is… | Specify | Reason |
|---|---|---|
| Maximum peel adhesion to metal surfaces | Polyken 345SW | 68 oz/in vs. 47 oz/in for 3M 425 — about 45% stronger |
| High-temperature duct, heat shielding & "hot spot" applications | Polyken 345SW | Rated to 350°F vs. 300°F long-term for 3M 425 |
| AMS-T-23397B / MIL-T-23397 or Gulfstream-approved tape | Polyken 345SW | Explicitly lists these specs; 3M 425 does not |
| Paint stripping & electroplating masking | Polyken 345SW | Solvent-resistant acrylic adhesive with clean removal |
| Extreme cold applications (below −40°F) | 3M #425 | 3M 425 rated to −65°F; Polyken rated to −40°F |
| Moisture / vapor barrier with documented WVT data | 3M #425 | 3M publishes a 0.77 g/m²/24h transmission rate; Polyken does not |
| Conformability over tight irregular contours | 3M #425 | Higher elongation (6% vs. 3%) |
Polyken 345SW specifications from Berry Global TDS (rev. 4/11/18) and Product Information Sheet. 3M 425 specifications from 3M Technical Data Sheet (rev. May 2022). 3M lists its values as "representative or typical" and not for specification purposes; Polyken adhesion/tensile values are per PSTC test methods while 3M values are per ASTM — verify certified values against your applicable specification before use.