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Flame test
How does elastomer identification work?
The flame test, or spark test, can be used to identify the elastomer type. To do this, hold as small an amount of rubber as possible in a small flame. The rubber can then be determined by its burning behavior, smell and the resulting residues. Compare the properties for this with the following table.
| Rubber type | Burning behavior | Odor | Backlog |
| NR | Burns very well. Yellow, even flame | Characteristic odor | Sticky, greasy, soft |
| NBR | Burns very well. Uneven, flickering flame | Crumbles, slightly greasy | |
| CR | Self-extinguishing, does not burn in its own flame | Pungent odor | Firm and grainy. Not greasy |
| IIR | Burns well. Yellow, sooty flame | Faint odor | A little greasy |
| EPDM | Burns very well. Sooty flame | Pungent odor | Fine-grained, slightly greasy |
| CSM | Does not burn in its own flame. Bright smoke when burning. Bright glow on the rubber, even a few seconds after removing the flame | Corrosive odor | Very fine-grained |
| FKM | Does not burn in its own flame. Bright smoke when burning. | Very strong, pungent odor | Hardly any residue |
| PU | Does not burn in its own flame. Liquefies immediately on contact with the flame | Strong characteristic odor | Very soft or liquid residue that can even drip |
| VMQ (silicone) | Does not burn in its own flame. Yellow-white flame with white smoke. Burning point turns white | Little intense odor | Solid and white |
CAUTION: When burning, rubber can release toxic decomposition products into the air. Therefore, only use the smallest possible rubber sample and only smell it carefully.
