Stainless steel buying guide: grades, finishes, and shapes

Which stainless steel should you buy?

304, unless your part will live near salt water, pool chemicals, or road salt, then it's 316. Those two grades are our whole stainless rack, and between them they cover nearly everything stainless gets asked to do: railings, brackets, brew gear, boat hardware, machined parts. 304 is the default. 316 is the upgrade you buy for one specific enemy, chlorides.

304 owns the default spot because of its recipe. The trade name is 18-8: roughly 18% chromium and 8% nickel. The chromium grows an invisible oxide skin that heals itself every time the surface gets scratched, which is the whole stainless trick. The nickel keeps the steel tough and formable instead of hard and cranky. Corrosion resistance, workability, looks, and price all meet in the middle at 304, and that's why most of the rack is 304. Still weighing stainless against aluminum and plain steel? Our project decision guide sorts that out first.

When do you need 316 instead of 304?

The moment chlorides enter the part's life: ocean spray, wharf and boat hardware, pool and hot tub fittings, anything washed in de-icing salt all winter. 316 takes the 304 recipe and adds 2-3% molybdenum, the one ingredient that resists the pitting chlorides cause. Away from salt, 316 buys you nothing 304 wasn't already doing.

Near the coast, the honest marker is tea staining: within about 5 km of the surf, bare 304 slowly browns. It's cosmetic, the metal underneath keeps working, but it reads as rust on a part you wanted bright, and 316 resists it far better. The cost step is smaller than its reputation: a 12″ piece of 1/2″ round bar is $9.68 in 304 and $12.73 in 316 as of June 2026, about 30% more. When the call is close, our 304 vs 316 guide settles it shape by shape.

Is 304 stainless food safe?

Yes, with one honest qualifier. 304 is the grade most food equipment is already built from: commercial counters, sinks, brew kettles, dairy and processing tanks. The food-equipment standard NSF/ANSI 51 covers stainless steel as a food-zone material, and 304 is the grade fabricators reach for first, with 316 stepping in around heavy brines.

The qualifier: we sell raw bar and sheet, not certified equipment. "Food safe" is judged on the finished piece, its welds, crevices, and cleanability, by whoever inspects it, so no raw stock arrives "certified". What we can prove is the metal itself. Ask for a mill test report with your order and you'll have the mill's measured chemistry for your exact pieces, on a single 12″ piece if that's the order. One practical note from food jobs: smooth surfaces clean up best, which is what makes 2B sheet the sane starting point.

Why does a magnet stick to some stainless?

Because cold work makes 304 slightly magnetic, and most stainless picks up some cold work on its way to you. In the soft annealed state, 304 and 316 barely react to a magnet. Rolling, drawing, straightening, and bending transform a sliver of that soft structure into a harder form that does pull, so the fridge-magnet test mostly measures the part's history, not its grade.

You'll see it at the rack: bar can show a faint pull, since bar gets straightened and worked after rolling, while sheet in the annealed 2B state mostly won't. Bend a 304 bracket and the corners will grab a magnet hardest, because that's where the cold work went. 316 stays the most stubbornly non-magnetic of the family. None of it changes corrosion resistance, and "real stainless never holds a magnet" is a myth; a magnet can't tell grades apart, paperwork can.

What finishes and shapes can you order?

Nine shapes and two finishes. The shapes: round bar, flat bar, pipe, sheet, square bar, angle, hex bar, square tube, and tube, mostly 304 with the common sizes repeated in 316. The finishes: plain sheet is 304 in the 2B mill finish, and round, square, and hex bar come smooth finished, the ST in our product titles.

2B is the finish stainless sheet leaves the mill with: cold rolled, annealed, pickled, then one last light pass through polished rolls. It reads as a smooth, soft grey sheen, not a mirror. Smooth finished (ST) bar arrives with a clean, uniform surface, ready for the lathe or the weld table as it lands. After a brushed or mirror look? That's a polishing step you do afterward, and 2B is the right surface to start from. The whole rack lives in the stainless steel collection: pick a shape, type your length in inches, and the price shows up, cut free to ±1/8″.

What should you know before drilling, cutting, or welding it?

Plan around work hardening. Austenitic stainless hardens the instant a tool rubs instead of cuts, and a work-hardened spot will eat the next drill bit you send at it. The cure is technique, not muscle: slower speed than mild steel, firm steady feed, a sharp bit, cutting oil, and never let the bit sit and spin in the hole.

Cobalt bits buy forgiveness on 316 and thicker sections. Sawing and grinding follow the same logic: fresh teeth or a fresh disc, steady pressure, and ventilation, since stainless fume and dust carry chromium you don't want to breathe. On welding, the honest caveat: on thick sections, weld heat can make standard 304 prone to corrosion right beside the bead. Chromium carbides form at roughly 425-815°C and steal the chromium the surface needs; low-carbon 304L exists to solve exactly that. Thin material with quick passes rarely sits in that range long enough to matter for shop fab. Our rack is standard 304 and 316, so if your drawing names an L grade, that's a sourcing request. The simplest move of all: order your pieces at final length and skip most of the cutting.

What does stainless steel cost as of June 2026?

Here's the June 2026 snapshot, cut included. A 12″ piece of 304 round bar runs $5.77 at 1/4″ and $9.68 at 1/2″. The same 1/2″ piece in 316 is $12.73, and a 12″ x 12″ piece of 16-gauge 304 2B sheet is $16.46. All prices in CAD, and they update daily with the metal market, so check the product page for today's number.

Volume discounts of 5-15% apply automatically as the order grows, and the $40 order minimum clears with any mix of metals and shapes. Pieces ship up to 96″ anywhere in Canada, and under 48″ they ride the best parcel rates. Price the grade decision per piece, not by reputation: the 316 upgrade above costs $3.05 on a $9.68 part. For how stainless sits against aluminum, steel, and brass, our Canadian metal price guide has the full June 2026 table. Drawing names 304L, a mirror polish, or a stick past 96″? Send a quote request; sourcing runs 2-21 days, and you'll see the price before you commit.