some months. others a couple of weeks before it started dripping.
I found leaving the portafilter locked in place to keep it warm when the machine was left on would speed up the process i assume because the hot portafilter is in direct contact with the main surface.
Yeah I think it's a combination of the compression and heat. I leave my portafilter in the machine at all times (unless adding/removing coffee), but just not fully locked in. My protafilter rotates around 90 degrees so I usually leave it around 45-60 unless I'm pulling a shot with it.
some months. others a couple of weeks before it started dripping.
I found leaving the portafilter locked in place to keep it warm when the machine was left on would speed up the process i assume because the hot portafilter is in direct contact with the main surface.
edit: missed Mick's reply.