Winsteard's Etchant
Winsteard's Reagent
Material Specific
Composition
Ethyl alcohol 80–90%, Hydrogen chloride 2–5%, Picric acid 0.5–1.5%, Methyl alcohol 0.5–5%
PACE product, by weight
Method
Immersion or swab
Time
10–60 s
Alternative Names
Tags
Reveals
Prior austenite grain boundaries, tempered martensite, carbides in martensitic SS (410, 420, 440C), PH stainless (17-4 PH, 15-5 PH), and hardened tool/HSS
Typical Results
Vilella's-family etchant (picric + HCl + denatured ethanol) with sodium tridecylbenzene sulfonate added as a surfactant/wetting agent. The wetting agent reduces surface tension and produces more uniform attack on hydrophobic polished surfaces than straight Vilella's. Use case identical to Vilella's: prior-austenite grain boundary reveal in hardened martensitic / PH stainless and tool / high-speed steels.
Application Method
Method:Immersion or swab
Typical Time:10–60 s
Preparation Notes
PACE Winsteard's Reagent is supplied ready-to-use. Composition (by weight):
| Ingredient | CAS No. | % | Hazardous |
|---|---|---|---|
| Ethyl alcohol | 64-17-5 | 80–90% | Yes |
| Hydrogen chloride | 7647-01-0 | 2–5% | Yes |
| Picric acid | 88-89-1 | 0.5–1.5% | Yes |
| Water | 7732-18-5 | 0.5–1.5% | No |
| Methyl alcohol | 67-56-1 | 0.5–5% | Yes |
| Isopropyl alcohol | 67-63-0 | 0.5–5% | Yes |
| Sodium tridecylbenzene sulfonate (40% solution) | 26248-24-8 | 4–5% | No |
Application Notes
Immerse or swab 10–60 s at room temperature. Rinse with ethanol, then water; air-dry.
Troubleshooting
PICRIC ACID: never let solution dry. Dry picric crystals are shock-sensitive explosives. Keep ≥0.5% water in container at all times. The surfactant reduces surface tension, so solution may bead-and-run on overly horizontal surfaces.
Storage Notes
Amber glass at room temperature; keep wet. Inspect monthly and add water if level drops. EXPLOSIVE WHEN DRY. Stable months when wet.
Alternative Etchants
- Vilella's Reagent
- Adler's Etchant
- Carpenter's
Similar Etchants
- Vilella's Reagent