"Cold spot" on my heated bed?

[old man emu]

How essential is it to have a fan on the extruder? I'm coming into winter now and room temperature is down to about 15C.

There are plenty of fan shroud stls on thingiverse I could print.

OME

[printbus]

Some random thoughts...

Have you tried repositioning the clips for the glass? The MK1 I got with my i3v kit wasn't very flat, which I assume is typical. It could be that you've got a spot on the heat bed that bows away from the glass as mounted, and repositioning clips might help. Or add a few more?

Another thread mentions your use of kitchen foil between the heat bed and the glass. I'm curious on the reason for that. It'll add more required soak time before printing, won't it? I remember a picture somewhere showing ripples in the foil. Couldn't inconsistent ripples in the foil lead to variations on how heat is being conducted to the glass?

You mentioned the room temperature being 15 degrees C. Is that adding a challenge to ABS printing? I haven't done anything in ABS, but printing in a cool room seems contrary to reading how some people use a printer enclosure to keep the print area warm for ABS.