Heart rate sealer material - epoxy?


Is there any particular reason why Garmin is using this very soft (epoxy?) material at the back of the watch? (as opposed to glass for example?).

This material can be cracked/scratched very easily (and unfortunately I had many scratches on my previous Fenix 5x).

  • You mean the black ring housing the OHR / Pulse Ox sensor array? On the Fenix it is made of stronger stuff than the Forerunners, I know that.

  • Hopefully it's better than what was used on my Vivoactive 3. That sensor cover got cracks all over the place after less than a year, and it definitely wasn't caused by any sort of impact. I suspect it might've been sunscreen/bugspray that caused it. Garmin says not to let sunscreen or bugspray touch the watch, but sometimes that's easier said than done.

  • It helps not to place the watch face up on a table or any other surface, put it down on its side instead.

    Also if you have been to the beach, make sure you take your watch off and wash any sand off your wrists.

    It sounds simple but there is no reason why the sensor cover should get scratched if it's only ever in contact with clean skin. Even so, the OHR on the Fenix is made from higher quality materials which should be more impervious to swirl marks and scratches compared to the one on the back of the Forerunner 245/645/935/945.

  • I have a 6X and 945 and to me the OHR appears to be identical. One is not built better than the other, they appear the same. My old 5X sensor developed cracks just the same as my 935 did. Both were replaced under warranty. This is very much a Garmin quality issue and is not something I've heard of with other manufactures. 

  • Why oh why can they not just put a sapphire ohr crystal on the back. I would go back to Garmin if they did. I’ve had several that have developed sensor cracks. I switched to the Apple Watch 5 as the base model has a ceramic and sapphire back. I haven’t been dealing with all the software bugs that come along with the new Garmin wearables. The ohr is accurate and not at all erratic. It doesn’t have all the metrics, but for a leisurely runner it does the job. 

  • Bought my f5x at public release, and never had any cracks.

  • It may have to do with the sweat properties of each person. A lot of people have had the issue. Salt and plastic don’t always get along.