Harris Stay-Silv 15 (part number 15620F1) is a phos-copper silver brazing alloy classified AWS A5.8 BCuP-5, packaged as a single-tube flat rod — 0.050 in × 1/8 in (1.3 × 3.2 mm) — ideal for HVACR technicians, plumbing contractors, and maintenance shops who need a standard quantity (one tube) rather than the bulk 5 lb supply. The alloy contains 15% silver, 5% phosphorus, and 80% copper, matching the industry-standard composition for air conditioning and refrigeration copper brazing. The phosphorus acts as a self-fluxing agent on copper-to-copper joints. The flat rod profile melts evenly across wider joint faces and is easy to feed into standard ACR fitting gaps. Complies with AWS A5.8, ASME SFA-5.8, QQ-B-654A BCuP-5, EU REACH, and RoHS directives.
| Property | Value |
|---|---|
| AWS Classification | AWS A5.8 BCuP-5 |
| ASME Specification | ASME SFA-5.8 BCuP-5 |
| Other Standards | QQ-B-654A BCuP-5; ISO 17672 CuP 284; BS 1845-CP1 |
| Silver (Ag) | 14.5 – 15.5 % |
| Phosphorus (P) | 4.8 – 5.2 % |
| Copper (Cu) | Remainder (~80 %) |
| Solidus | 1,190 °F (643 °C) |
| Liquidus | 1,480 °F (804 °C) |
| Melting Range | 290 °F (161 °C) |
| Rod Form | Flat — 0.050 in × 1/8 in (1.3 × 3.2 mm) |
| Package | 1 tube |
| Part Number | 15620F1 |
| Self-Fluxing on Copper | Yes — no separate flux needed for Cu-Cu |
| Compliance | EU REACH; RoHS |
- HVACR service calls — single-tube format is convenient for service technicians who carry a few tubes per call-out rather than a bulk 5 lb supply
- Air conditioning installation — copper line set connections, service valve installations, and suction/discharge fitting brazements
- Plumbing repairs — copper pipe brazing for hot water, steam, and gas distribution systems where code permits brazing vs. solder
- Distributor and wholesale resale — unit-quantity packaging for shelf sale to contractors purchasing on a per-job basis
- Light commercial refrigeration — walk-in cooler copper piping, display case connections, and condenser coil outlet joints
Phosphorus (4.8–5.2%) in Stay-Silv 15 reacts with surface copper oxide during heating, converting it to copper phosphide which acts as a cleaning and wetting agent. This eliminates the sticky brazing flux typically required with silver alloys (BAg series), saving time on each joint and eliminating the post-braze flux cleanup step on copper-to-copper joints. Flux residue corrosion — a common service issue on poorly cleaned brazed copper joints — is eliminated when BCuP-5 alloys are used correctly on copper.
Critical limitation: BCuP alloys must never be used on steel, stainless steel, or cast iron. Phosphorus reacts with iron to form brittle iron phosphide (Fe₂P), which can cause the joint to fracture under pressure or vibration. When brazing copper to a ferrous fitting or valve body, use Safety-Silv 45 (BAg-5) or Safety-Silv 56 (BAg-7) with Stay-Silv White Flux.
For standard ACR tube sizes (3/8 in – 7/8 in), an air-acetylene torch with a proper tip size provides adequate heat without risking over-heating the alloy or burning out the flux on silver alloys. Heat the fitting shoulder first, then sweep to the tube to equalize temperature. When the flux (if used) becomes water-clear and the base metal is uniformly hot, apply the flat rod to the joint gap. The alloy should flow immediately by capillary action without needing flame contact on the rod.
- 15620F1 (1 tube) — ideal for service trucks, small contractors, and try-before-bulk purchasing. Approximately 28 sticks per tube depending on cut length.
- 15620F5 (5 lb tube) — bulk format for high-volume HVACR shops or wholesale resale. Best per-troy-oz value. Same alloy, same specification.
- What is the difference between 15620F1 and 15620F5?
- Identical BCuP-5 alloy — only the package size differs. 15620F1 is a single tube (~28 sticks); 15620F5 is a 5 lb bulk tube at lower cost per troy oz.
- Can I use Stay-Silv 15 on copper-to-brass joints?
- Use a small amount of Harris Stay-Silv White Flux on brass — BCuP-5 is fully self-fluxing only on pure copper. Never use BCuP alloys on steel or stainless steel.
- Does Stay-Silv 15 need shielding gas?
- No — it is a torch-applied brazing alloy, not a MIG wire. The phosphorus provides self-fluxing action on copper without any gas shielding.
- What AWS standard covers Stay-Silv 15?
- AWS A5.8 BCuP-5 / ASME SFA-5.8 BCuP-5.
Browse the full brazing alloy and welding wire collection. Compare to the Harris Stay-Silv 15 — 5 lb tube (15620F5) for bulk purchasing, and the Harris Stay-Silv 15 brazing strip (15S0051) for pre-placed brazing applications. Specification reference: Harris Products Group and AWS A5.8.