Ruspert Coated 304 Stainless Steel Bi-Metal Roofing Screws
This is the top of our roofing range: a 304 stainless steel bi-metal screw protected by Ruspert ceramic coating, with a hardened drill point welded on for steel-to-steel installation. It pairs stainless-grade corrosion resistance with an extra barrier against the salt, UV and heat of severe coastal and island environments.
Features and Benefits
- Non-magnetic 304 austenitic shank — the corrosion baseline is stainless, not a coating fighting for its life
- Ruspert three-layer system: zinc phosphate base, metallic zinc layer, baked ceramic topcoat
- Dark-grey architectural finish that matches modern panel systems and eliminates galvanic mismatch with aluminum
- Laser-welded hardened drill point — weld torque and drill capacity tested per batch
- Cold-forged and processed below the sensitization window (450-900 °C), keeping the shank ductile and wind-vibration resistant
What Ruspert Coating Adds to Stainless Steel
Ruspert is a three-layer system — zinc phosphate base, metallic zinc layer, and a baked ceramic topcoat. On a stainless body it delivers a neutral dark-grey finish that matches architectural panels, eliminates galvanic mismatch with aluminum roofing, and adds UV stability that bare stainless cannot offer.
Typical Applications
- Severe coastal and offshore-influenced roofing projects
- High-end architectural standing seam systems
- Airports, stadiums and landmark buildings
- Roofing over swimming pools and humid interiors
- Any roof specified with a 25+ year fastener life
Model Specifications
| Diameter | Threads per Inch | Drill Point | Total Steel Thickness | Length Range |
|---|---|---|---|---|
| 4.8 mm | 14 / 16 / 20 / 24 | No. 1-No. 5 | 1.0-12.0 mm | 22-125 mm |
| 5.5 mm | 14 / 16 / 20 / 24 | No. 1-No. 5 | 1.0-12.0 mm | 22-125 mm |
| 6.3 mm | 14 / 16 / 20 / 24 | No. 1-No. 5 | 1.0-12.0 mm | 22-125 mm |
Coating System
| Layer | Thickness | Function |
|---|---|---|
| Zinc phosphate base | conversion layer | Adhesion foundation |
| Metallic zinc | 2 μm | Sacrificial protection at contact points |
| Baked ceramic topcoat | 20 μm, sintered max. 220 °C | Barrier against salt, UV and heat |
Installation Guidelines
- Use a depth-setting screw gun at 0-2,500 rpm with the correct hex socket.
- Apply steady pressure through the drilling phase; the point must clear the steel before the thread engages.
- Stop at a uniform EPDM compression ring — the stainless backup washer should not grind the panel.
- Confirm three full threads beyond the supporting steel.
- On aluminum panels this screw removes the galvanic penalty — pair it with the aluminum-backed EPDM washer option.
Why Source from BuildFastener
Every container ships with weld inspection records, coating thickness data and salt-spray certificates. For specification work, our engineers provide drill-capacity tables, spacing recommendations and compatibility reviews against your panel material. Request samples and experience the difference in driving feel.
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