Brass Sheet Metal: Forming, Cartridge Stock, and Why Zinc Content Rules

For anything that bends, draws, or stamps, default to C260 cartridge brass (70 percent copper, 30 percent zinc). It offers the best cold formability in the brass family, which is exactly why it was developed for drawing ammunition cases, and it handles tight bends, deep draws, and stamping without cracking. Avoid C360 free-machining brass for formed sheet work entirely: the lead and higher zinc that make it the 100 percent machinability benchmark also make it crumble and crack when bent, so it belongs in machined bar parts, not folded sheet. If your part needs both forming and some machining, C260 is the safer base since it can be machined adequately even though it is not free-machining. Cost-wise, C260 and C360 are similar per pound, so the choice is driven by process, not price. The quick rule: bends and draws mean C260; heavy machining with no bends can use C360; mixing tight bends with C360 is a design error.

Dezincification is a selective corrosion attack where zinc leaches out of high-zinc brass in saltwater, brackish water, or acidic conditions, leaving behind a weak, porous, copper-rich structure that loses strength and eventually crumbles. Ordinary cartridge brass like C260 is susceptible, so it is the wrong choice for marine or aggressive-water service even though it forms beautifully. The fix is grade selection: naval brass (C464) adds about 1 percent tin to inhibit the attack and is the standard for marine hardware, seawater fittings, and fasteners, while dezincification-resistant (DZR) brasses with small arsenic additions go further for potable water and harsh service. Lower-zinc red brasses are also more resistant. The key is to specify the service environment, not just the appearance: a decorative indoor part is fine in C260, but anything exposed to salt spray, seawater, or acidic water must move to naval brass or a DZR alloy. Skipping this turns a part that looks perfect at shipment into one that fails by apparent dissolution months later.

Yes on both counts, and these are among brass's best fabrication traits. Brass solders and brazes readily, which is the normal way to assemble brass sheet components, terminals, and decorative parts, and it conducts heat well enough to join cleanly without the extreme heat input pure copper demands. It also plates well, taking nickel, chrome, tin, and gold finishes with good adhesion. That plating versatility matters because most brass parts are chosen partly for appearance, and bare brass tarnishes over time. Common finishes include clear lacquer to preserve the bright gold look on decorative parts, nickel or chrome plating for durable hardware, bright dipping and polishing for a mirror finish, and tin or nickel plating on electrical contacts to keep contact resistance low. Budget the plating or lacquer step into price and lead time since it batches at an outside processor. During fabrication, protect the surface with film and careful handling, because scratches and tool marks are highly visible on the warm metal and show through clear finishes.

Brass is the right pick when you want a blend of properties that neither pure copper nor steel delivers cleanly. Compared to copper, brass is harder, stronger, far easier to machine and shear, much cheaper, and it tarnishes more slowly, while still carrying useful (though lower) electrical conductivity, around 28 percent IACS for C260 versus copper's 100 percent. So for connectors and electrical parts where moderate conductivity is acceptable but you need better strength, machinability, and cost, brass beats copper. Compared to steel, brass adds corrosion resistance, the decorative gold appearance, easy soldering, and good formability, which is why it dominates decorative hardware, lamp parts, instrument components, and plumbing fittings. Choose copper only when maximum conductivity is essential, choose steel when you need structural strength at the lowest cost and can coat for corrosion, and choose brass when the part needs the middle ground: looks, corrosion resistance, formability, and easy joining without copper's softness, gumminess, and price. Match the grade to the environment, escalating to naval brass for marine exposure.