Compare two rubber-bond peel results only after checking the method, specimen geometry, loading arrangement and reported output. A 90-degree and a 180-degree description identify different arrangements; the angle alone does not provide a conversion between their results.
Start with the purpose of the comparison. Material development, process control and a finished-component investigation can require different specimens and acceptance criteria. Record which task the test is intended to support.
Name the method, not just the angle
ASTM D429 covers several methods for rubber adhesion to rigid substrates. Its public scope includes a 90-degree stripping arrangement among other specimen configurations. That does not mean every test labelled “peel” uses the same geometry or reports the same property.
Request the full method and edition, specimen preparation and any agreed departure from that method. For a production part, show how the specimen was obtained and held. Identify the rubber, substrate, surface specification and any preparation or conditioning relevant to the comparison.
Keep the force record and units together
| Report field | What to check |
|---|---|
| Force or normalized force | Whether the output is a force, force per specimen width or another defined quantity |
| Reported statistic | Whether the value is a peak, average over a defined interval or another method-defined result |
| Specimen dimensions | The actual width, rubber section, substrate and bonded region |
| Loading | Angle, rate, fixture and any movement or deformation affecting the arrangement |
| Conditioning | Temperature, exposure, elapsed time and specimen preparation |
| Separation | Location, extent, photographs and how mixed separation was described |
Keep the trace or force record when it is needed to interpret a reported average or peak. Normalizing by width does not erase differences in geometry, loading or the region evaluated. A larger number from a different arrangement is not sufficient evidence of a better bond.
Report where separation occurred
Photograph both sides of the separated sample and identify rubber remaining on the substrate, exposed surfaces and any tear within the rubber. Map mixed regions rather than assigning a single label to the entire sample. Preserve the orientation and loading direction.
The rubber-to-metal failure investigation guide explains how those observations connect with component and service records. The observed location helps structure the investigation; proving a particular manufacturing or service cause requires additional evidence.
Design a comparison that answers one question
For candidate constructions, agree which variables remain the same and which change. Use the same method and acceptance basis where a direct comparison is required. If an existing customer method differs, define how each result will be used instead of creating an unsupported numerical conversion.
For a failed part, retain an unused comparison sample from the relevant lot where available. Identify whether extraction or cutting altered the surfaces. Keep the test result linked to the compound, insert and drawing revision.
Keep component duty separate from static adhesion
A static adhesion result does not supply a repeated-load or assembled-function result. Where the part will see oscillating load, temperature cycling or media exposure, specify that evaluation with its own specimen, sequence and acceptance criterion.
Send RubberQ the bonded-part drawing and existing reports to discuss the comparison. Review rubber-to-metal component requirements and agree the test and reporting scope before using a peel value in a supplier decision.