well not really free but cheap.....and it looks like depron, not sure if is is. went to the dollar store and picked up 8 sheets of what they call "foam board" it has one side with colored paper on it, and one side plain white. first you remove the colored side....best done by rolling it off.....then on the white side, soak with windex, wait about 3 mins. and it darn near slips off the foam. you end up with a 20in.x30in. 4.5mm thick of some nice flat phlatprinter food. oh yea, i paid $1.10 per sheet. once ya get the paper off its really lite, peace, randy.
color side, roll paper off....

tag....called readiboard...

phlatprinter food....4.5mm thick

 

Nice tip Randy
thanks for posting
Mark

 

thanks mark, did some research and found out this is depron. randy.