Homebrew PCBs

Hi,

 

I use 20mil sewing pins (available at sewing supply stores) which are, I
think, brass coated, steel pins to align 2 layers. These pins are very handy
for all sorts of things - they solder easily and are very sharp. For example
they make excellent probe tips.

 

Anyway, I print two diagonally opposite alignment holes (vias or pads) just
outside the trace area on both layers when designing the board. I then use a
plain paper template and tape it to the copper on one side and drill the two
alignment holes. After printing the toner transfer paper I use a pin to
punch holes in the transfer paper. Using two pins I align the top and bottom
layer. Next the transfer paper is taped to the copper with Scotch tape. Make
sure the copper board is slightly larger than the prints to allow using the
Scotch tape.

 

Using this method, I regularly achieve alignment accuracy approaching +\-
1mil.

 

On a slightly different subject, I noticed in some recent posts that glossy
photo paper is used in laser printers. Am I correct? I have never tried it
because I was told that the melting temperature of the paper coating is too
low and the heat roller in the laser printer gets gummed up.

 

Am I missing something here?

 

Frank  VK4BLF



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