New Heated Bed?

[Andrew Jepson]

I've noticed that the heat distribution on my heated bed is uneven, and despite a number of modifications to ensure even heating and a perfectly level bed, I'm still having issues printing large parts. I think it's time to upgrade, as I've already got a nice piece of MIC6 precision aluminum plate and extra PEI to stick on top. I tried using my stock heat spreader and it takes a looong time to heat up that .25" thick aluminum plate, although heat is definitely more uniform. I thinking that it would be a good idea to get a 110v silicone heater pad, so I thought I'd ask and see if anyone else has gone this route. Does anyone remember what type of thermistor Ezra used for the heated bed? Also, any recommendations on what relay to use in between a 110v heater and the RAMPS board.

[Glenn Beer]

You need an SSR solid state relay to drive a heater like that. 

See http://www.phidgets.com/docs/Solid_State_Relay_Primer for more info about SSR's.