I am starting to shift away from the Prusa build manual now as I move into the parts which are quite different to the original’s. Sadly the heated bed is one of those parts with the MK42 not really available yet, so I have to make do with a 3mm MK3 from Banggood.

Of course it is not flat, about 1mm lower in the middle than the edges, so I make a support to try and pull it level as it is tightened down.

I also put a piece of 3mm ply between the support frame and the bed, mostly for thermal insulation.

Quick solder job and the wires are on and the thermistor is stuck in place with common silicone sealant. I see some people use high temp sealant, not sure why. Your average bathroom sealant (RTV) is good for a constant 200°C which this bed will never get to.

I have also seen people use huge wiring for the heated bed. I used 2mm² wire which is good for 25 Amps. If I run the bed at 24V (which I intend to) it will max out around 8 Amps… with losses of 70mV and 560mW. So I am OK with that.

That is all of the initial mechanical build done. Next up – the electronics 🙂