Homebrew PCBs

Chris, I have not tried an waffle iron, but I got a 1 inch thick piece 
of steel (4x5x1 inch) and lapped it to make a very flat surface, 
attached a thermo couple to it. Using a hot plate to heat the iron block 
to to the target temperature then placing this on my PCB/toner image 
sandwich and clamping it with a toggle clamp with about 400  pounds of 
pressure for about 1 minute (20 pounds per square inch).  This gives me 
consistent results.
The target temperature is established for the toner formulation your 
printer uses.  This involves taking an image on a piece of paper and  
while monitoring the temp of the hot plate, looking at the toner with a  
magnifier and using a sharp pointed probe and noting the softening temp 
and the melting temp (my toner melts at about 320 degrees F) The melting 
temp is when the toner becomes glossy (shiny). The pressure and temp 
combination will determine the amount of image spreading that will occur 
. On small pitch traces you may adjust the temp/pressure/time 
combination for best results. For very fine pitches, I use  a temp of 
about 280 degrees (this will just tack the image to the  copper) then I 
take this tacked PCB/toner/paper sandwich and place it on the hot plate 
and raise it to the toner melting point (without pressure) ... this will 
cause good adhesion of the toner to the copper with minimum image spreading.
Jim KI6MZ

Chris Trask wrote:
>     I'm very much interested in trying this laser toner transfer method for
> homebrewing single-sided PC boards, and the thought came to me that perhaps
> an electric waffle iron would be a more practical alternative than using a
> clothes iron.  With the PC board material and the paper sandwiched between a
> couple of pieces of aluminum or copper plate, the heat and pressure would be
> more uniform and it would become a matter of applying the pressure for a
> suitable amount of time.
>
>     But without any strawberries or blueberries.  :{b
>
>     Has anyone ever tried this approach?
>
> Chris
>
>      ,----------------------.       High Performance Mixers and
>     /    What's all this     \    Amplifiers for RF Communications
>    / extinct stuff, anyhow?  /
>    \  _______,--------------'           Chris Trask / N7ZWY
>   _ |/                                  Principal Engineer
>  oo\                                  Sonoran Radio Research
> (__)\       _                             P.O. Box 25240
>   \  \    .'  `.                     Tempe, Arizona 85285-5240
>    \  \  /      \
>     \  '"        \                 IEEE Senior Member #40274515
>      .       (  ) \
>       '-| )__| :.  \              Email: christrask@...
>         | |  | | \  '.       http://www.home.earthlink.net/~christrask
>        c__; c__;  '-..'>.__
>
>                        Graphics by Loek Frederiks
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>
>
>