Homebrew PCBs

Hi folks.
  Well, after much experimenting with a SECOND laminator like the 
first, I have determined that my printer's toner must just melt at 
too high a temperature.  (I have an HP Color LaserJet 4500N, and an 
HP LaserJet 5si, both of which produce the same results). I have, as 
such, ripped the fuser out of an old HP LaserJet IIIp.
  I fired it up and watched it, thinking the little thermostats 
touching the hard fuser roller that are in-line with the AC power 
would turn it off when it got hot enough...bad idea there.  One of 
the plastic parts supporting the roller that encircles the lamp 
melted.  Luckily, I caught it before it deformed it too badly.  
Those thermostats must only be for extremely high temperature 
protection, but not enough to prevent damage.  So, note to self, 
temperature regulation circuitry required.  Fortunately, it looks 
like HP's own built in thermostat will work just fine.
  For everyone who has been experimenting with fusers, how hot do 
you let yours get for optimal melting?

-Josh