I have to add some resistors to an aluminium plate on a 3D printer, because it only goes to 67'C without foam insulation. The heated bed currently reads 1.6 ohms (90W at 12V)
I wish to add about 96W of resistors to the aluminium plate, to run on 12V, to reach 110 degrees in 10 minutes. There is a 3cm margin of free aluminium at both ends for attaching resistors.
Are $4 Chinese power resistors like this reliable at 110 degrees? I can't find their temp rating and mean time before failure.
If use 2s2p of 1.5 ohm 50W resistor, same as 2x 100W 3 ohm resistors, it'll draw 96W, with 104W of safety in case i insulate the resistors?
I am going to:
- buff the aluminium contact surfaces
- glue them with arctic silver adhesive/bolt them
- insulate the underside so that the heat goes into the aluminium
- put them on a different power supply with an on/off switch
Am i missing some pitfalls?