Aluminum Suppliers and Machining in Mobile, AL: Aerospace Plate to Marine Hull Alloy

Because of the Airbus and Austal demand base, Mobile-area distributors typically stock a wider range of aluminum than comparable mid-size cities. General-purpose 6061-T6 bar, plate, and extrusion and 5052-H32 sheet are almost always on the shelf in common sizes. Aerospace plate such as 7075-T6, 7075-T73, 7050, and 2024-T3 is often available in standard thicknesses because local aerospace suppliers turn it regularly, and marine plate in 5083-H116 and 5456 moves through distribution feeding the shipyard cluster. Where you will still hit a mill lead time is on non-standard tempers, thick aerospace plate in odd dimensions, clad 2024 in specific gauges, or any alloy needing full AMS certification in a size nobody locally stocks. A practical approach is to confirm cert requirements up front: if your part needs AMS 4045 or ABS traceability, ask the supplier whether their on-hand stock carries the paperwork, because uncertified shelf stock cannot be substituted into a traceable build no matter how identical the alloy.

Aerospace-tier shops in the Mobile area routinely hold +/-0.0005 in on critical features and tighter on bores and bearing interfaces using 4- and 5-axis machining centers. On 7075 and 2024 fittings, achievable flatness and positional tolerances depend heavily on stress relief and fixturing, because high-strength aluminum moves as residual stress relaxes during material removal. Good shops rough, stress-relieve, and finish in stages to hold geometry on thin-walled aerospace structures. For general 6061-T6 work, +/-0.001 to +/-0.005 in is typical and inexpensive. The real differentiator locally is not just the tolerance number but the inspection and documentation: AS9100 shops provide first-article inspection reports to AS9102, CMM data, and full traceability, which is what Airbus-tier and defense work demands. If your part is purely commercial, you can save cost by using a non-aerospace shop that still machines accurately but does not carry the overhead of formal aerospace quality systems.

Mobile's salt air and humidity make corrosion the dominant service-life factor for aluminum. The 5000-series marine alloys like 5052, 5083, and 5456 resist seawater and salt spray without any coating, which is exactly why Austal builds aluminum ship hulls from them. The 6000-series, such as 6061, performs well when anodized or chromate-coated and is fine for most structural and equipment use. The high-strength 2000- and 7000-series alloys are different: 2024 and 7075 contain copper and zinc that make them strong but far more prone to corrosion, including stress-corrosion cracking. That is why aerospace structures destined for coastal or marine service often specify 7075 in the T73 temper rather than T6, accepting slightly lower strength in exchange for much better stress-corrosion resistance. Bare 2024 must be clad or coated. Getting the alloy and temper right at design time prevents premature failure that a coating alone cannot reliably stop in this environment.

Usually not in the same building, and that is by design. Aerospace machining and marine fabrication are different disciplines with different equipment, certifications, and culture. Aerospace shops are precision machining houses with AS9100 systems, climate-controlled inspection, CMMs, and tight-tolerance 5-axis work on relatively small high-value parts. Marine fabrication shops are built around large-format cutting, certified structural welding to AWS D1.2, forming heavy plate, and assembling big weldments. Mobile is unusual in having a strong supplier base for both because of Airbus and Austal respectively, so a buyer can source either capability locally, but you should match the shop to the job rather than expecting one vendor to excel at both. ManufacturingBase lets you filter Mobile suppliers by capability, so you can route a tight-tolerance 7075 fitting to an AS9100 machining shop and a 5083 weldment to a certified marine fabricator without guessing.

Given the coastal environment, finishing is a core part of local aluminum supply rather than an afterthought. Standard available options include Type II sulfuric anodize for general corrosion protection and cosmetics, Type III hardcoat anodize for wear resistance on tooling and high-contact surfaces, and chromate conversion coating (chem film) per MIL-DTL-5541 where you need corrosion protection plus electrical conductivity or a paint base. Powder coat and marine-grade primer-and-topcoat systems are also widely available for parts that see direct weather exposure. For aerospace work, finishers provide these to the relevant AMS and MIL specs with documentation. The key planning point is that anodize masks and racking add lead time, and hardcoat changes dimensions slightly (it grows roughly half the coating thickness outward), so machinists in Mobile typically account for the anodize buildup on close-tolerance features before plating. Discuss the finish with both the machine shop and the finisher early so tolerances and masking are coordinated.