Magnesium Suppliers and Machining for Spokane, WA Aerospace and Equipment Builders

Spokane sits in the orbit of the Pacific Northwest aerospace supply chain, and the city's machine shops have decades of experience feeding that demand with lightweight metals. Magnesium earns its place when a part has to be light and stiff at the same time. Its density runs about 1.74 g/cm3 versus 2.70 for aluminum, so a magnesium casting can be a third lighter than the same part in 6061. For an avionics chassis or a handheld field instrument, that difference decides whether a soldier or technician carries it comfortably for a full shift. The second reason is damping. Magnesium absorbs vibration and shock far better than aluminum, which is why gearbox housings and instrument frames in heavy-equipment cabs sometimes spec it over cheaper alloys. Spokane's equipment builders, who supply mining, forestry, and agricultural markets across the Inland Northwest, value that quiet running and reduced operator fatigue. The tradeoff is cost and corrosion sensitivity, so magnesium is a deliberate engineering choice rather than a default.

AZ31B is the workhorse wrought alloy, supplied as sheet, plate, and extrusion. It contains roughly 3 percent aluminum and 1 percent zinc, formable when warm and weldable with the right filler. Spokane sheet-metal shops use it for brackets, panels, and enclosures where a part is bent or stamped rather than cast. Expect to warm-form AZ31B between 230 and 290 C because it has limited cold ductility. AZ91D is the dominant die-casting alloy, with about 9 percent aluminum and good castability for thin-wall housings produced in volume. It is the alloy behind most magnesium gear cases and electronics enclosures. WE43 is the specialty grade: a yttrium and rare-earth alloy that holds strength up to about 250 C, which is why it appears in helicopter transmission housings and missile components. WE43 also costs several times more and demands tighter supplier qualification, so confirm certification and traceability before committing a flight program to it.

Magnesium machines beautifully, with low cutting forces and excellent surface finish, but the chips and fines are flammable. Any Spokane shop quoting magnesium work should have a dedicated process: sharp tooling, generous depth of cut to avoid fine dust, dry machining or a mineral-oil coolant rather than water-based fluid, and a Class D fire extinguisher or dry-sand bucket on the floor. Never use water on a magnesium fire. Ask a prospective supplier how they segregate magnesium swarf, because mixing it with steel or aluminum chips in a common bin is a real hazard. Corrosion protection is the other non-negotiable. Bare magnesium corrodes galvanically when coupled to steel or aluminum fasteners, so parts are typically chromate-converted, anodized via a process like Tagnite or Keronite, or epoxy-primed. For aerospace work, the finish callout is part of the drawing and usually a NADCAP-controlled line. Confirm your supplier can deliver the specified conversion coating, not just bare machined parts.

Few shops stock raw magnesium on the shelf the way they stock aluminum, so lead time planning starts with the mill or distributor. AZ31B sheet and extrusion typically come through national metal distributors with West Coast warehouses, putting material in Spokane within days. AZ91D and WE43 castings are sourced from specialty foundries, often outside the immediate region, so a cast part may carry four to eight weeks of lead time before machining even begins. The practical move for Spokane buyers is to separate the supply question from the machining question. Many local shops will machine and finish magnesium competently but expect you to bring the certified material or a qualified mill source. Use ManufacturingBase to identify which regional suppliers actually hold magnesium capability and current aerospace certifications, then build your timeline around casting or extrusion lead time first.