Fry's Etchant
Fry's Reagent
Material Specific
Composition
Ethyl alcohol 55–70%, Hydrogen chloride 30–50%, Copper (II) chloride 0.4–2%, Methyl alcohol 1–5%
PACE product, by weight
Method
Swab
Time
30–120 s
Alternative Names
Tags
Reveals
Strain patterns (slip lines, deformation banding); grain boundaries in low-carbon and maraging steels; recrystallized vs unrecrystallized regions; prior cold-work boundaries
Typical Results
Classical Fry's reagent: CuCl2 + HCl + ethanol + water. Workhorse for visualizing strain history and cold work in low-carbon and maraging steels (250, 300 grades). The water content (5–15%) is what enables the strain-pattern attack; water-free Kalling's chemistry does NOT produce the same result.
Application Method
Method:Swab
Typical Time:30–120 s
Preparation Notes
PACE Fry's Reagent is supplied ready-to-use. Composition (by weight):
| Ingredient | CAS No. | % | Hazardous |
|---|---|---|---|
| Ethyl alcohol | 64-17-5 | 55–70% | Yes |
| Hydrogen chloride | 7647-01-0 | 30–50% | Yes |
| Water | 7732-18-5 | 5–15% | No |
| Copper (II) chloride | 7447-39-4 | 0.4–2% | Yes |
| Methyl alcohol | 67-56-1 | 1–5% | Yes |
| Isopropyl alcohol | 67-63-0 | 1–5% | Yes |
Application Notes
Swab 30–120 s at room temperature. The brownish-purple attack pattern is normal. Rinse with water then ethanol.
Troubleshooting
False strain patterns from polishing damage: finish polish with 0.05 µm alumina or VibroMet to remove the cold-worked surface layer before re-etching.
Storage Notes
Amber glass at room temperature. Stable several weeks; discard when very dark.
Alternative Etchants
- Adler's Etchant
- 2% Nital
- Klemm's Reagent
Similar Etchants
- Adler's Etchant