Genuine or non oem HP toner works for me. For the pitting problem I
transfer craft metallic foil on top of the toner before etching. It's a
well known practice and reliable.
Rather than using acetone or citronella to prepare/clean the copper I
use 220 grit sandpaper and an iso-propyl wipe which makes the toner
'grip' the oil free copper. Even fingerprints can interfere so handle
the edges of the PCB. As a test I polished/lapped copper and tried the
identical transfer with poor results all other things being the same.
Also, before I did the metal foiling, I used to use a silver sharpie to
'fill' in the toner transfer for any breaks or potential pitting and
then etch.
I have done literally hundreds of double sided boards and even boards
for RF use to 1Ghz with toner transfer. It works.
Ancel
transfer craft metallic foil on top of the toner before etching. It's a
well known practice and reliable.
Rather than using acetone or citronella to prepare/clean the copper I
use 220 grit sandpaper and an iso-propyl wipe which makes the toner
'grip' the oil free copper. Even fingerprints can interfere so handle
the edges of the PCB. As a test I polished/lapped copper and tried the
identical transfer with poor results all other things being the same.
Also, before I did the metal foiling, I used to use a silver sharpie to
'fill' in the toner transfer for any breaks or potential pitting and
then etch.
I have done literally hundreds of double sided boards and even boards
for RF use to 1Ghz with toner transfer. It works.
Ancel