1. Focus on the smell of product
For the low quality sealing strips, you can smell a pungent odor for a long distance.But for the one in high quality,the EPDM rubber sealings have no odor, only the original plastic taste.
2. Focus on the appearance of product
When touch the sealing strip in low quality,you will feelthat it is rough and hard, and the tension is not good. On the contrary, the appearance is smooth and bright, and feels soft and elastic.
3. Compare the weight of product
The heavier the weight, the worse the quality. If you find that the sealing strip on your hand is heavier than the daily product, the manufacturer uses heavy calcium or talcum powder as the filling material; the good quality sealing strip is filled with calcium carbonate raw material so that the proportion is lighter.
4. The test of high-temperature function
The sealing strips in low quality will change color when exposed to high temperature and contact surfaces, and the surface will be stained with dust, and yellowing and oil seepage will occur;the ones in good quality will be aging after long-term exposure.
5. Burn the sealing strip to compare
After burning,the rubber strips become black ash ,and have a certain viscosity, but the epdm rubber sealing strip is burned into white ash, and it becomes the small powder.