Marine Fastener Material Guide
Salt water is brutal on fasteners. Choosing the right marine material — and avoiding incompatible metal pairings — is the difference between hardware that lasts for decades and hardware that pits, stains, or seizes in a season. This guide compares the three marine-grade families we supply: silicon bronze, 316 stainless, and brass.
Silicon Bronze vs 316 vs Brass
| Material | Salt-Water Resistance | Strength | Best For |
|---|---|---|---|
| Silicon Bronze | Excellent | Moderate | Wooden boats, bronze hardware, below-waterline, architectural coastal |
| 316 Stainless | Excellent (above water) | Higher | Rigging, deck hardware, structural marine; needs oxygen to stay passive |
| Brass | Fair | Low | Light fittings, trim, freshwater — not for prolonged salt immersion |
Silicon Bronze
The traditional choice for boatbuilding and coastal architecture. Silicon bronze resists salt-water corrosion beautifully, ages to a stable patina, and is galvanically compatible with bronze fittings and the other metals common on a boat — so it avoids the dissimilar-metal corrosion you can get from mixing metals. It is also a safe choice below the waterline. Strength is moderate; for high-load rigging, 316 is stronger.
316 Stainless
316 contains molybdenum for excellent chloride resistance and is stronger than bronze or brass, making it the workhorse for rigging, deck hardware, and structural marine connections above the waterline. One caution: stainless relies on an oxygen-fed passive layer, so in low-oxygen settings (tight crevices, permanently submerged, under marine growth) it can suffer crevice corrosion — which is exactly where silicon bronze shines.
Brass
Brass is fine for light fittings, trim, and freshwater, but it is not a true salt-water material — in prolonged marine exposure it can dezincify and weaken. Use it for decorative and low-load freshwater work, and choose bronze or 316 for real marine duty.
Avoiding Galvanic Corrosion
When two dissimilar metals touch in salt water, the less-noble one corrodes faster. The safe approach is to keep a joint within one family: bronze fasteners with bronze hardware, 316 with 316. Avoid pairing brass or plain steel with stainless or bronze in the splash zone. When a mixed joint is unavoidable, isolation washers and bedding compound help. Ask us and we'll spec a compatible marine set.
Frequently Asked Questions
What is the best fastener material for salt water?
Silicon bronze and 316 stainless are the two marine-grade choices. Silicon bronze is best for below-waterline, bronze-hardware, and crevice-prone joints; 316 is best for higher-strength above-water rigging and deck hardware. Brass is only for light freshwater or decorative use.
Is silicon bronze better than 316 stainless for boats?
It depends on the location. Silicon bronze excels below the waterline and in low-oxygen crevices where stainless can suffer crevice corrosion, and it pairs with bronze hardware. 316 is stronger and ideal for above-water rigging and structural hardware. Many boats use both, each where it is strongest.
Can I use brass fasteners in salt water?
Not for prolonged exposure. Brass can dezincify and weaken in salt water. Use it for light fittings, trim, and freshwater, and choose silicon bronze or 316 stainless for marine duty.
How do I prevent galvanic corrosion on a boat?
Keep each joint within one metal family (bronze with bronze, 316 with 316), avoid pairing brass or plain steel with more-noble metals in the splash zone, and use isolation washers and bedding compound where a mixed joint is unavoidable.
Marine Fasteners: Bronze, 316 & Brass
Silicon bronze (full range, drop-shipped), 316 stainless, and brass nuts, bolts, and washers — specified compatible for your application.