Magnesium Machining & Supply in Tacoma, WA

The Puget Sound region runs on weight reduction. Every gram pulled out of a flight component compounds into fuel savings over a 25-year airframe life, and the Boeing supplier network that threads through Tacoma, Auburn, and Frederickson has institutionalized that mindset across its tier-two and tier-three shops. Magnesium delivers a stiffness-per-unit-mass that aluminum cannot match in certain geometries, which is why it still appears in gearbox housings, electronics enclosures, and seat structures. Beyond aerospace, Tacoma's renewable-energy work has created secondary demand. Lightweight magnesium components show up in portable power systems and instrumentation packages where field crews carry the hardware by hand. Local machinists who already hold AS9100 paperwork for flight work are comfortable extending the same process discipline to these energy customers, which keeps lead times tight for buyers who don't want to ship the work out of state.

AZ31B is the wrought workhorse, supplied as sheet, plate, and extrusion. With roughly 3% aluminum and 1% zinc, it offers good formability and weldability, and it is the grade most Tacoma sheet-metal shops will reach for when a customer wants a lightweight panel or bracket bent and riveted into an assembly. Typical sheet tempers are O (annealed) and H24 (strain-hardened), with the latter giving a tensile strength near 290 MPa. AZ91D is the dominant die-casting alloy, carrying about 9% aluminum for castability and tightly controlled iron, nickel, and copper to hold corrosion resistance in check. Pierce County casters and the buyers who source from them use AZ91D for complex housings where net-shape production beats machining from billet. WE43 is the premium option: a rare-earth alloy (yttrium plus neodymium) engineered to hold strength at elevated temperatures, which is why defense and high-end aerospace programs spec it for components that see sustained heat. Expect WE43 to carry a significant cost and lead-time premium and to require a supplier comfortable with heat treatment to the T6 condition.

Magnesium machines beautifully, often at the highest surface speeds in the shop, with low cutting forces and excellent chip formation. The catch is fire risk: fine magnesium chips and dust ignite readily, and water-based extinguishment makes things worse. Tacoma shops that run magnesium regularly segregate it from aluminum and steel work, use dedicated tooling, keep Class D extinguishing media on hand, and manage chip accumulation aggressively. This is the single biggest filter when sourcing locally. A shop that runs magnesium as a routine alloy has the housekeeping, ventilation, and operator training to do it safely; a shop touching it occasionally is a higher risk on both quality and safety. When you list a magnesium job on ManufacturingBase, name the grade and whether the work is wet or dry machining so the responding shops self-select on actual capability rather than guessing.

Bare magnesium corrodes, and the marine air around Commencement Bay accelerates it. Almost every Tacoma magnesium part ships with a protective finish. Chromate conversion coatings per the older MIL spec are being displaced by chrome-free conversion treatments and anodizing processes such as the trade-name systems that build a hard ceramic-like layer. Buyers should specify the finish on the drawing and confirm the supplier or its plating partner can hit it. Many Tacoma machinists subcontract finishing to specialized Puget Sound platers, so a magnesium quote often bundles machining plus an outside-processing line item. Asking for that breakout up front prevents surprises and lets you compare quotes on equal footing.