Carpenter's Reagent
Carpenters
Material Specific
Composition
Ethyl alcohol 35–55%, Hydrogen chloride 35–55%, Nitric acid 2–5%, Ferric chloride 1–5%
PACE product, by weight
Method
Swab
Time
5–30 s
Alternative Names
Tags
Reveals
Carbides (M6C, MC, M23C6), prior austenite grain boundaries, and tempered martensite in tool/high-speed steels and hardened martensitic stainless
Typical Results
Classical Carpenter Steel Co. formulation: FeCl3 + CuCl2 + HCl + HNO3 + denatured ethanol. One of the most aggressive of the stainless / tool-steel family. Reveals carbide morphology and prior-austenite grain size in fully hardened tool steels (M2, T1, D2, A2, S7) and martensitic stainless.
Application Method
Method:Swab
Typical Time:5–30 s
Preparation Notes
PACE Carpenter's is supplied ready-to-use. Composition (by weight):
| Ingredient | CAS No. | % | Hazardous |
|---|---|---|---|
| Ethyl alcohol | 64-17-5 | 35–55% | Yes |
| Hydrogen chloride | 7647-01-0 | 35–55% | Yes |
| Nitric acid | 7697-37-2 | 2–5% | Yes |
| Ferric chloride | 7705-08-0 | 1–5% | Yes |
| Copper (II) chloride | 7447-39-4 | 0.5–1.5% | Yes |
| Methyl alcohol | 67-56-1 | 0–5% | Yes |
| Isopropyl alcohol | 67-63-0 | 0–2% | Yes |
Application Notes
Swab 5–30 s at room temperature. Rinse with water, then ethanol.
Troubleshooting
Solution depletes faster than Kalling-family etchants because of the HNO3 content. Discard when color darkens significantly or smell of NOx develops. Pitted attack from over-dwell on one spot.
Storage Notes
Amber glass at room temperature. Stable a few weeks; replace when very dark or NOx-smelling.
Alternative Etchants
- Vilella's Reagent
- Adler's Etchant
- Kalling's No. 2
Similar Etchants
- Adler's Etchant
- Vilella's Reagent