I don't think the ceramic fiber blanket is necessary. I made my own reflow oven (PID temperature controlled) and was surprised to find that my roommate was able

I don't think the ceramic fiber blanket is necessary. I made my own reflow oven (PID temperature controlled) and was surprised to find that my roommate was able to reflow a PCB with his completely unmodified toaster, just popping the PCB in and bringing it up to the right temperature. Obviously it didn't follow the temperature curve like mine did, but the end result wasn't really different, at least for our hobbyist uses.