Understanding the result
Use this calculator to prepare a shellac solution from dry flakes and a measured alcohol volume, or to estimate the cut of a known mixture. In traditional usage, a one-pound cut means one pound of dry shellac per US gallon of alcohol; the calculator uses approximately 120 g per litre per pound-cut as a convenient rounded conversion. Actual final solution volume will differ from solvent volume.
- These results support research and planning; they do not independently establish authenticity, age or value.
- Keep direct observations separate from assumptions, seller claims and conclusions.
- Seek qualified, object-specific advice when the decision affects value, repair, safety or a legal transaction.
Good records improve research
Keep original observations separate from conclusions. Photograph the whole object and relevant details in even light; record dimensions, labels, maker marks, repairs, provenance and the references consulted. Do not alter the object just to obtain another clue.
Methodology and limitations
For mixing mode, dry shellac required ≈ 120 g × cut strength × alcohol litres. For reverse mode, cut strength ≈ shellac grams ÷ (120 × alcohol litres). This is a conventional approximation; weigh flakes and measure alcohol consistently. Dissolution time and filtration depend on shellac grade, flake age and preparation conditions.
A 2-pound cut with 500 mL alcohol requires approximately 120 g of shellac flakes under the rounded conversion. Treat the alcohol volume as solvent volume, not the exact final solution volume.
Historical objects are often repaired, refinished, reassembled or made from more than one material. Modern reproductions may imitate older processes. A likely match should always be phrased as a research hypothesis unless it is supported by a qualified, object-specific assessment and trustworthy documentation.
Frequently asked questions
What does a two-pound cut mean?
It traditionally means two pounds of dry shellac flakes per US gallon of alcohol. This calculator uses the approximate metric equivalent of 120 grams per litre per pound-cut.
Will the final mixture volume equal the alcohol volume?
No. Dissolved flakes affect the final volume. The calculator reports the solvent amount used and the estimated flake mass, not an exact final volume.
Does shellac type affect the calculated mass?
The ratio is a weight-to-solvent estimate, while wax content and grade affect finish properties and suitability. Confirm the intended shellac type for the conservation or finishing task.
What safety precautions matter?
Alcohol vapours are flammable. Follow the product safety data, use suitable ventilation, keep away from ignition sources, and store materials in approved containers.
Can this tell me whether shellac is the original finish?
No. It calculates mixtures and does not identify existing finishes or establish the history of an antique surface.
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