Homebrew PCBs

I've got some solder and rosin flux powders coming through the mail.  It 
looks like I might have to flat bed that printer pretty soon after all. 
 I might get time to chop it this weekend, but we are spring cleaning 
the garage this weekend (and last weekend, and the one before...), so 
it's a toss up on whether I get the time or not.  If I do, I'll try 
printing  some circuits onto cardboard.  I think the flux will be enough 
to stick the solder to the board that way.  I just hope the solder melts 
@ < 451 F.  I don't want a half baked toaster oven on my hands.  That's 
about 230 C, isn't it?  I'm going to have to check the data sheets 
first, maybe I will be doing it on roughened FR4.  I'll keep you posted.
Richard