How to read a reverse engineering report, and what a good one must contain

A buyer's guide to compound analysis reports: scope, methods, results with units, confidence statements and the limitations section that tells you how far to trust it.

Beginner2 min readArticleUpdated 2026-10-23All polymers
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A report is only useful if you can tell how far to trust it. Look for these seven things.

1. A scope that matches your question

The first page should say what was asked, what sample was received (with identification and condition), and what level of analysis was done: identify, profile or match.

2. Methods stated for every result

"Polymer: HNBR" is not enough. "Polymer: HNBR, identified by ATR-FTIR and pyrolysis-IR, confirmed by Tg −34 °C (DSC, 10 °C/min)" is. Every number should have its method and conditions beside it.

3. Results in weight percent and phr

Weight percent is what was measured. Phr is what was calculated. A good report shows both and explains the conversion and any corrections, such as the sulfur correction.

4. Ranges where precision is limited

Blend ratios, oil types and accelerator identifications rarely deserve a single number. Look for ranges and qualifiers such as "sulfenamide-type accelerator" instead of a made-up name.

5. A physical property table with conditions

Hardness, density, tensile, modulus, elongation, compression set, fluid swell and low-temperature tests, each with standard, temperature, time and sample type.

6. A candidate formulation clearly labelled as such

A reconstructed recipe is a hypothesis. Look for words like "proposed" or "estimated" and a statement of how it will be validated.

7. A limitations section

What the analysis could not determine: exact curatives, supplier grades, mixing history, trace additives. Also the rights statement: who confirmed the right to analyse the sample, and a statement that no approvals are implied.

Red flags

  • A single "exact formula" with no uncertainty.
  • No method references.
  • Percentages adding to well over or under 100 without comment.
  • Silence about limitations.
About this article. It is original writing prepared from public sources, standards and general industry practice. It is not a copy of any book or standard and it is not engineering advice. Confirm values against the current edition of the standard and test in your own application. Only analyse material you own or are entitled to analyse.

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