Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Hi
I have posted in the photos section my first sucessful dual sided PCB.
Many thanks to all who have posted their results and ideas. Though I
am a lurker, I used a lot of your collective knowledge. Thanks !!

I never thought that toner transfer could get to 16 mil trace/12
space.

I think I'll give a try at 8 mil trace/space next. But for now this
is all I need for the mega88 in a 32tqfp.

I'll post when it is all soldered up and when it is running the
robot.!!

P.S I love the samsung ML-2250 printer($99 after rebate). My only
regret is not getting the postscript version ($100 more). I had to
mess with the EPS file from eagle to get the right page size/scaling
( defaults to A4) and then print using Ghostview. I think that I'm
not really getting the 1200 dpi resolution from the windows driver..
WE will see on my 8 mil tests.


Thanks
Dave

Process used:

Made using Staples #471861 paper.
Samsung ML2250 printer in 1200 dpi mode.
Eagle CAD-> exported to eps. Edit PS header From "A4" size to "letter"
Then Ghostview for printing.

Align both papers and tape 2 edges to form a pocket. Set cleaned pcb
in the pocket and hand iron for ~2mins on highest setting. cool fo 5
mins and then soak for 10 mins in hot sink water. Peal off paper as
much as possible after 5mins and let soak remaining 5 mins.

Use fingers to rub of more paper, Then us scrub pad ( teflon safe) to
get a better clean. Use a soft toohtbrush in betwwen pads to do
final cleanup of clay from tight spaces.

Dry, Inspect and re-clean with toothbrush and water.

Etch 12-15mins in 6"x6" square tupperware container of FErric Chloride
(radio shack). container filled 3/8" deep (2-3oz)
Place closed container in sink filled with 2" hot tap water.
Constant agitation ( back and forth) for 12 mins.

open container, check for unetched places. If small ( <0.25") use
paper towel soaked in etchant to rub off the remaining coper in this
area. This prevents overetching the res of the board for one
stubborn area. clean , inspect uner magnification. Use paper towel
method again if needed.

Drill on drill press with backer underneath using carbide bits
(0.020" for vias).

Clean off toner with laquer thinner.

Solder!!!