Thermistor Hole in Center of MK3 Heatbed

I'm working on a complete rebuild of my i3 and bought the following MK3 ALU heatbed on amazon.

[www.amazon.com]

The only thing that has me stumped is the hole in the middle. I understand that the thermistor is supposed to mount there but what about the top surface? My plan was to print directly on the ALU surface, will this hole be old open? Can I fill it with a dab of Silicon glue that I used on the other side to secure the thermistor in place?

Thanks in advance!

Andy

Or a piece of Kapton tape.

Ok, thanks!

Yeah I filled mine with kapton, damn stuff peels off anytime I'm printing a very tight first layer or have changed something and the nozzle clearance is a bit low. Was thinking of either second aluminium plate on top, or glass, but I'm using an inductive sensor. So it's a case of changing to capacitative sensor and maybe using a sheet of printbite which is very good.

When I researched these mk3 beds I was lead to believe they had a pcb for a soldered on surface mount thermistor and therefore no centre hole. But this is clearly just one version.

I haven't covered this hole and have printed right over if with no issues... I think it's small enough that the tension in the plastic keeps everything straight