The one-line answer to 8011 vs 1235 aluminum foil: 8011 is the strong, iron-bearing foil for packaging that has to resist tearing and hold a heat-seal; 1235 is the pure, formable foil for deep drawing, lamination and electrical work. 8011 gets its strength from iron and silicon; 1235 gets its formability and conductivity from 99.35% purity.
Both roll down to the same ultra-thin gauges — 0.006 to 0.20 mm — but they are built for opposite ends of the foil business.
The chemistry is the whole story
| 8011 | 1235 | |
|---|---|---|
| Aluminum | remainder | 99.35% min |
| Iron | 0.60 – 1.00% | 0.40% max |
| Silicon | 0.50 – 0.90% | 0.25% max |
| Si + Fe | — | 0.65% max |
| Copper | 0.10% max | 0.05% max |
| Typical tensile (O) | ~100 MPa | ~80 MPa |
| Typical tensile (H18) | ~180 MPa | ~165 MPa |
| Character | strong, tear-resistant | pure, formable, conductive |
8011 is a deliberate Al-Fe-Si alloy: the iron and silicon form fine dispersoids that resist tearing and pinhole formation as the strip is rolled down to foil gauge. That makes it the stronger, more puncture-resistant foil — and the workhorse of packaging.
1235 is high-purity foil stock. The tight control on iron and silicon (Si+Fe capped at 0.65%) keeps the surface clean and the etch uniform, which is what matters for capacitors, batteries and lamination.
Where 8011 wins
- Household wrap and container foil. 8011 resists tearing and holds a fold, which is what kitchen foil actually needs.
- Pharmaceutical blister lidding. The heat-seal and puncture resistance of 8011 make it the standard for blister foil, usually in H14/H18.
- Air-conditioner fin stock. 8011-H22/H24 at 0.08–0.20 mm is the common heat-exchanger fin alloy.
- Lid and container stock that has to be formed and then survive handling.
Where 1235 wins
- Capacitor cathode foil. The uniform etch that 1235's purity allows is the whole point of electrolytic capacitor foil.
- Battery current collectors. 1235-H18 at 0.009–0.020 mm gives the clean, stable surface that coating and etching lines need.
- Flexible packaging lamination. Where the foil is drawn or laminated, 1235's formability and clean surface win.
- Cable shielding. High conductivity and purity make 1235 the choice for EMI shielding foil.
Pinhole count is the real acceptance criterion
For both grades, but especially for barrier foil, the number that actually decides whether a lot ships is pinhole count — the number of microscopic holes per square metre. A foil with too many pinholes loses its barrier and fails its purpose no matter how good the alloy chemistry is.
This is why the order matters more than the grade. For barrier foil, state the pinhole acceptance level, the gauge, the temper, and whether the foil is single-zero (0.01–0.1 mm) or double-zero (<0.01 mm). For food or pharma contact, ask for the food-contact or pharma declaration — the compliance comes from the declaration and any coating, not from the alloy designation alone.
How to choose
| Your foil | Choose | Temper |
|---|---|---|
| Household wrap, container | 8011 | O / H18 |
| Pharma blister lidding | 8011 | H14 / H18 |
| AC heat-exchanger fin | 8011 | H22 / H24 |
| Capacitor cathode | 1235 | O / H18 |
| Battery current collector | 1235 | H18 |
| Lamination, cable shielding | 1235 | O / H18 |
What gets ordered wrong
The first error is assuming the grade decides food or pharma compliance. It does not — the declaration and the coating do. Name the end use and ask for the declaration.
The second error is specifying 1235 where puncture resistance matters. 1235 is pure and formable but not as strong as iron-bearing 8011; a 1235 blister lidding will puncture more easily. That is 8011's job.
The third error is treating the two as interchangeable on a certificate. They are different alloys with different composition limits, and a 1235 certificate does not satisfy an 8011 order. For electrical foil especially, the grade is load-bearing in the design.
Bottom line
8011 for strength and heat-seal, 1235 for purity and formability. Packaging that has to resist tearing is 8011; foil that has to be drawn, laminated or etched uniformly is 1235. State the pinhole level, gauge and temper — those decide the lot more than the grade name does.
See the 8011 and 1235 grade pages for the composition tables. If you have a foil application and are not sure which side of the line it sits on, tell us the end use and gauge — the answer is usually immediate.