In the world of general-purpose aluminum, two alloys stand out above all others: 1100 and 3003. Together they account for a significant share of global aluminum flat-rolled product demand. Both are affordable. Both form well, weld well, and resist corrosion effectively. And in many catalogues, they appear side by side at nearly identical prices.

So what actually separates them — and when does the difference matter?

The short answer: 1100 is commercially pure aluminum, chosen when purity, thermal conductivity, or electrical performance is critical. 3003 adds manganese to gain roughly 20% more strength with minimal trade-offs elsewhere. For most general fabrication work, 3003 is the default. For food contact, chemical handling, heat exchangers, and electrical applications, 1100 is often the only correct choice.

This guide compares 1100 and 3003 aluminum sheet across properties, tempers, applications, corrosion behavior, fabrication characteristics, and price — with a practical decision table you can use today.

1. What Makes 1100 and 3003 the Two Most Common General-Purpose Alloys

1100 aluminum is a commercially pure alloy containing at least 99.0% aluminum. The remaining fraction consists of small amounts of copper, silicon, and iron — trace elements that have minimal effect on properties but are present in commercially refined aluminum. 1100 is the softest and most formable wrought aluminum alloy in common commercial use.

3003 aluminum starts with a similar base but adds 1.0 to 1.5% manganese. Manganese is a solid-solution strengthener: it dissolves into the aluminum matrix and restricts dislocation movement, raising strength without significantly affecting corrosion resistance, formability, or weldability. The result is an alloy that behaves very similarly to 1100 in the shop but delivers meaningfully better mechanical performance in service.

Neither alloy responds to heat treatment. Both are strengthened by cold working — the rolling and drawing operations that align the grain structure and increase hardness. This is captured in the H-series temper designations (H12, H14, H16, H18, H24) that appear alongside the alloy number on every mill certificate.

These two alloys cover a wide range of industrial needs: food packaging, chemical storage, building products, HVAC systems, heat exchangers, cookware, and general sheet metal fabrication. Understanding which fits your project is straightforward once you know what separates them.

2. 1100 vs 3003: Full Property Comparison

The table below compares 1100 and 3003 aluminum in the H14 temper — the most common commercial specification for flat-rolled sheet in both alloys.

Two numbers deserve particular attention. First, thermal conductivity: 1100 delivers 222 W/m·K versus 163 W/m·K for 3003 — a 36% advantage. For heat exchanger fins, where thermal efficiency is calculated directly from conductivity, this difference is significant and often decisive. Second, the strength gap: 3003-H14 provides 152 MPa tensile strength versus 124 MPa for 1100-H14. That 20% increase may seem modest, but in roofing and structural panel applications where span length and wind or snow load determine required material thickness, it allows a thinner gauge of 3003 to match the performance of a heavier gauge of 1100 — at lower cost and weight.

3. Temper Guide: H12, H14, H16, H18, H24, and O Explained

Both 1100 and 3003 use the same H-series temper system. The temper number tells you how much cold work has been applied after annealing — and therefore how hard and strong the material is compared to its fully annealed (O temper) baseline.

O temper (fully annealed)

The softest condition. Material has been annealed to relieve all work hardening. Maximum ductility and formability. Used for deep drawing, hydroforming, and any application requiring the tightest bend radii or most complex shapes. Tensile strength for 1100-O is approximately 90 MPa; for 3003-O, approximately 110 MPa.

H12 — quarter hard

Light cold work applied after annealing. Strength rises modestly above O temper while retaining most of the forming capability. Used where some rigidity is needed but significant bending or drawing is still required.

H14 — half hard

The most widely specified temper for general industrial sheet. A good balance of strength and formability. This is the standard specification for roofing sheet, HVAC duct blanks, tank blanks, and general fabrication stock. When a purchase order specifies 1100 or 3003 without a temper, H14 is typically what the supplier ships.

H16 — three-quarter hard

More cold work than H14, higher strength, reduced elongation. Used when a harder surface or higher stiffness is needed in the flat-sheet form, and when forming operations are limited to simple bends.

H18 — full hard

Maximum cold work. Highest strength in the H-series. Lowest ductility — tight bends may crack. Used for flat applications where the sheet is not formed after delivery: shims, liners, stiffening plates.

H24 — work-hardened and partially annealed

Cold-worked to H14 strength but then partially annealed to restore some ductility. A good temper for corrugated roofing sheet, where forming the corrugation profile requires moderate ductility, but the finished panel must retain decent strength. Common for 3003 roofing coil.

When placing an order, always specify both the alloy and the temper. Stating '3003 aluminum sheet' without a temper will result in the supplier's default, which is usually H14 — but confirming this avoids potential disputes on delivery.

4. Where 1100 Aluminum Excels: Purity-Critical Applications

1100 aluminum is the right specification when the physical or chemical properties unique to high-purity aluminum are required. In these applications, 3003 is not a substitute — the manganese addition changes the alloy's behavior in ways that matter.

Food packaging and containers

1100 aluminum is widely used for food containers, foil laminates, bottle caps, and packaging trays. The alloy meets FDA and EU food-contact regulations because it is free from alloying elements that could leach into food or affect taste. 3003 is also generally food-safe, but in applications where regulatory compliance must be documented, 1100 is the cleaner specification. When in doubt, 1100 is the standard choice for food-contact aluminum in global supply chains.

Chemical processing and storage tanks

High-purity aluminum resists a wide range of organic acids, aldehydes, and chemical solvents better than alloyed grades. The 1100 alloy has no manganese, which means there is no risk of manganese-related reactions in sensitive chemical environments. For tank liners, chemical vessel cladding, and equipment used in pharmaceutical or specialty chemical production, 1100 is the preferred specification.

3003 performs well in more common chemical environments such as petroleum products, water, and mild acids — and is used extensively for fuel and oil storage tanks. But for borderline or chemically aggressive environments, 1100 provides a more conservative and lower-risk choice.

Heat exchanger fins

This is arguably the most technically important application for 1100 aluminum. In a fin-and-tube heat exchanger, the aluminum fins conduct heat between the process fluid (in the tubes) and the surrounding air or secondary fluid. Fin efficiency — the fraction of the theoretical maximum heat transfer actually achieved — depends directly on the fin material's thermal conductivity.

1100 aluminum conducts heat at 222 W/m·K. 3003 aluminum conducts at 163 W/m·K. That 36% advantage in conductivity translates directly into better exchanger performance for the same fin mass — or the ability to use thinner fins and reduce material cost while maintaining performance. HVAC coils, refrigeration evaporators, radiators, and industrial process exchangers all benefit from 1100 fins.

Electrical and conductive applications

1100 has an electrical conductivity of approximately 59% IACS (International Annealed Copper Standard), compared to 41% IACS for 3003. For busbars, grounding straps, conductive foils, and any application where electrical resistance matters, 1100 delivers meaningfully better performance. 3003 is not appropriate for electrical applications where conductivity is a design criterion.

Reflective and decorative surfaces

The purer grain structure of 1100 produces a finer, more uniform surface after rolling. This translates to better reflectivity when polished and a cleaner, more transparent anodize film. Applications requiring mirror-finish or high-reflectivity aluminum — lighting reflectors, decorative trim, solar reflectors — specify 1100 for this reason.

5. Where 3003 Aluminum Excels: Strength Plus Versatility

For the majority of general industrial applications, 3003 aluminum is the better default choice. Its 20% strength advantage over 1100 costs virtually nothing in formability, weldability, or corrosion resistance — and it typically comes at a slightly lower price. This combination of properties makes 3003 the most widely used aluminum alloy in flat-rolled products worldwide.

Roofing sheet and wall cladding

Aluminum roofing sheet is one of the largest single applications for 3003. The alloy's superior strength allows roofing sheets to span purlins at wider spacing without deflecting under wind load or concentrated foot traffic. In corrugated or standing-seam profiles, 3003-H24 is the standard specification: the H24 temper provides the ductility needed to form the corrugation profile while retaining enough strength for structural performance.

Both 3003 sheet and 3003 roofing coil are available in a range of thicknesses from 0.3 mm foil gauge up to 6 mm plate. Common roofing thicknesses range from 0.4 mm to 1.2 mm depending on span and loading requirements. The alloy's corrosion resistance makes it suitable for roofing without paint or coating in many environments, though coated or anodized surfaces extend service life further in coastal or industrial atmospheres.

HVAC ductwork and air handling

Sheet metal ductwork for air handling and HVAC systems uses 3003 almost exclusively. The alloy forms cleanly into rectangular and round duct sections, handles the Pittsburgh lock-seam and button punch snap-lock joints used in standard duct fabrication, and seam-welds reliably. Its strength advantage over 1100 allows thinner gauges to meet the stiffness requirements of low-pressure duct systems, reducing both material cost and duct weight.

Storage tanks for liquids

3003-H14 is the industry standard for welded storage tanks handling petroleum products, aviation fuel, kerosene, lubricating oil, and water. The alloy's strength handles internal pressure and hydraulic load from full tanks, while its excellent weldability allows leak-free seam welds using standard MIG or TIG processes with ER4043 filler wire. 3003 tanks are lighter than steel equivalents and require no internal coating for most non-corrosive liquids.

Cookware and kitchen equipment

The cookware industry relies heavily on 3003 aluminum for pots, pans, baking trays, and kitchen equipment. The alloy's greater hardness compared to 1100 produces utensils that resist denting and surface damage better in commercial use. Deep drawing of cookware shapes from 3003-O blanks is a well-established industrial process, and the alloy's food-safe composition meets global food-contact regulations.

General industrial sheet fabrication

For sheet metal work where there is no specific purity or conductivity requirement — brackets, guards, covers, enclosures, trays, signs, and general fabricated parts — 3003-H14 is the default specification. It machines, bends, and welds as easily as 1100 but provides a stronger finished part. In most cases, a part designed in 3003 can use a thinner gauge than the equivalent 1100 design, reducing material cost and weight simultaneously.

6. Application Selection Guide

7. Corrosion Resistance: Both Alloys, Different Environments

Both 1100 and 3003 aluminum form a natural aluminum oxide layer on their surface when exposed to air. This layer is self-healing: if scratched, it reforms within seconds. It provides excellent protection against atmospheric corrosion, most fresh waters, and many chemicals.

Where 1100 has the edge

In environments involving concentrated organic acids, acetic acid, nitric acid, and many organic solvents, 1100 is the safer choice. The absence of manganese means there are no secondary alloying phases that could react differently from the base aluminum matrix. This single-phase character gives 1100 its predictable, well-documented chemical compatibility across a wide range of industrial reagents.

Where 3003 holds its own

In atmospheric exposure, fresh water, petroleum products, and mildly alkaline conditions, 3003 performs as well as 1100 in practical terms. The manganese addition slightly improves resistance to pitting corrosion in some electrolyte solutions. For outdoor roofing, ductwork, and storage tanks, 3003 provides all the corrosion resistance the application requires.

Environments to avoid for both alloys

Neither 1100 nor 3003 is suitable for prolonged exposure to strong alkaline solutions (such as caustic soda / NaOH), hydrochloric acid, or environments with high chloride ion concentrations combined with mechanical stress. For marine immersion applications or continuous seawater exposure, 5xxx-series alloys such as 5052 or 5083 are the correct specification.

8. Formability, Welding, and Surface Finishing

Deep drawing and bending

Both alloys in the O temper are among the most formable aluminum alloys available. Deep-drawn cookware, containers, and complex shapes are produced routinely from 1100-O and 3003-O blanks. 1100-O is marginally softer and achieves slightly tighter draw ratios in demanding tooling, but for most commercial deep-drawing operations the alloys are interchangeable in the O temper.

In H14 temper, both alloys bend cleanly to minimum inside bend radii of approximately 0.5 to 1.0 times the material thickness for 90-degree bends across the rolling direction. Tighter radii risk cracking and should be evaluated on the specific thickness and temper combination before production runs.

Welding

Both alloys weld well by MIG (GMAW) and TIG (GTAW) processes. Use ER1100 filler wire for welding 1100 to 1100. Use ER4043 filler for welding 3003 to 3003 or for mixed joints between the two alloys. ER4043 is silicon-bearing, which lowers the weld pool melting point and reduces cracking risk in the heat-affected zone. Weld strength in both alloys is lower than parent-metal strength in H-temper — the heat-affected zone anneals to near-O-temper properties — but this is well understood in design and accounted for in tank and vessel codes.

Anodizing

1100 anodizes to a bright, clear, highly transparent film. The high-purity grain structure produces an anodize layer with minimal inclusions, making it the alloy of choice for clear architectural anodize where a bright, mirror-like appearance is specified.

3003 anodizes well but produces a slightly warmer, less transparent film because of the manganese-rich intermetallic particles distributed through the grain structure. For most industrial and utilitarian applications this is not a concern. For decorative clear anodize on visible architectural components, 1100 — or 6063 — is preferable.

Both alloys accept powder coating and liquid paint with standard aluminum pretreatment (chromate conversion coating or anodize primer). For painted roofing sheet or coil, 3003 is the standard substrate.

9. Price Comparison: What You Actually Pay — and Why

Here is a fact that surprises many buyers: 1100 aluminum typically costs slightly more per kilogram than 3003, despite being the simpler alloy. This seems counterintuitive — pure aluminum should be cheaper than alloyed aluminum, right?

The reason is refinement. Commercially pure 1100 requires tighter control of iron, silicon, and other trace impurities during smelting, which adds process cost. The manganese in 3003 is a relatively inexpensive alloying addition that actually makes the alloy easier to produce at scale. The cost premium for 1100 is typically modest — in the range of $30 to $80 per tonne depending on market conditions — but it is real and consistent.

Beyond alloy pricing, the factors that most affect what you actually pay for aluminum sheet are:

• Gauge (thickness): Thinner sheet carries a higher processing cost per kilogram than thick plate. A 0.5 mm roofing sheet costs more per tonne than a 3.0 mm tank plate, regardless of alloy.

• Temper: O-temper material requires an annealing step that adds cost compared to H14, which is produced directly from the rolling mill. H18 full-hard material requires the most rolling passes and may be priced slightly above H14.

• Width and length: Standard widths (typically 1000 mm, 1219 mm, 1500 mm) are priced at stock rates. Non-standard widths or cut-to-length orders carry a premium for slitting or shearing operations.

• Surface finish: Mill-finish sheet is least expensive. Brushed, stucco-embossed, or pre-painted coil carries progressively higher prices.

• Order quantity: Coil and full-sheet orders at mill-run quantities (typically 5 tonnes or more) are priced at the lowest level. Cut pieces and small orders carry a service center premium.

For roofing and general industrial applications where neither purity nor conductivity is a design requirement, 3003 is typically the better value — stronger at a lower or equal price per kilogram. For heat exchangers, food processing, and chemical equipment, 1100 is the correct specification regardless of the small price premium.

10. Quick Decision Guide: 1100 or 3003?

Use the following criteria to determine the right alloy before requesting a quote.

Choose 1100 when:

• The application involves food contact and regulatory compliance (FDA, EU 10/2011) must be documented

• The material will contact aggressive chemicals or organic solvents where alloy purity affects compatibility

• The application is a heat exchanger fin, HVAC coil, or refrigeration evaporator where thermal conductivity is a design parameter

• Electrical conductivity is required (busbars, grounding, conductive foil)

• The specification requires a clear, bright anodize with no color tint

• Maximum softness is needed for deep-drawn complex shapes (use 1100-O)

Choose 3003 when:

• The application is roofing sheet, wall cladding, or corrugated roofing coil

• The material will be formed into HVAC ductwork or air handling components

• The end use is a welded liquid storage tank for petroleum products, water, or similar fluids

• The application is cookware, food processing equipment, or kitchen hardware where surface hardness matters

• The requirement is general-purpose industrial sheet fabrication with no specific purity or conductivity requirement

• Budget is a constraint and the 20% strength advantage of 3003 allows a thinner, lighter gauge to be specified

When either alloy works:

If your application is general sheet metal fabrication with no purity, conductivity, or high-load requirements, 3003-H14 is the standard default. It is stronger, widely stocked, and in most markets marginally less expensive than 1100. Start with 3003 and specify 1100 only when a specific technical requirement makes it necessary.

11. Why Source Your Aluminum Sheet From Us

We supply both 1100 and 3003 aluminum sheet and coil in a full range of tempers and dimensions. Our stock covers the most common industrial specifications, and we support custom orders for non-standard gauges, widths, and lengths.

• Full temper range: O, H12, H14, H16, H18, and H24 available in both alloys

• Wide gauge coverage: from foil-gauge sheet for packaging applications to heavier plate for tank and structural use

• Food-grade material available with appropriate certification documentation

• Mill Test Certificates (MTC) provided with every shipment for full chemical and mechanical traceability

• Surface finishes available: mill finish, brushed, stucco embossed, and pre-painted coil

• Export experience across Southeast Asia, the Middle East, Africa, Europe, and the Americas

• Fast RFQ response: provide alloy, temper, thickness, width, length, quantity, and any certification requirements — we respond within 24 hours

Whether you are sourcing aluminum roofing coil for a large construction project, heat exchanger fin stock for an industrial application, or food-grade sheet for packaging production, we have the material and documentation to support your procurement.

Contact us today with your specification and we will provide pricing and lead time promptly.