MrDEB
Well-Known Member
I just completed etching, drilling, tinning a 2x board.
used a combination of methods to register both sides = came out perfect!!
using PULSAR paper, I used cutePDF to print the top layer and silkscreen mirror the printed the bottom layer w/o mirror.
using expresspcb to design board. it has no provision for mirror
printed layers on plain paper then taped the PULSAR paper to print to save paper.
using the bottom layer (on design, indicate which is top and bottom. I couldn't figure it out so I added then printed) I taped to top of board.
Then drill 3 holes same size as push pins (pc design must have 3 holes "bulls eyes) in 3 corrners.
removed then taped transfer paper to bottom of board (pre-punch bulls eyes holes in paper.have enough area around design so tape doesn't interfere.
insert pins then place, tape the top layer transfer paper using pre-punched bulls eyes holes.
I use a laminator, transfer the image to clean copper.
I run the board through about 6-8 times in different directions.Have yet to lose any traces.
cool then remove paper. inspect paper for non transferred traces. etch board.
drill holes before using liquid tin (mistake tinning then drilling.hard to see pads etc.)Drilling after etching makes a slight crater so center punch is not necessary. I use a 65 drill bit in a drill press.
lightly sand board after drilling as you get nubs on back side. sand before tinning.
apply tin then apply silkscreen using same indexing method with pins.
I use liquid tin in a plastic bag, works good. I get about 4 small boards before it doesn't work as fast.
the etching solution = 1 1/2 parts muratic acid to 2 parts hydrogen peroxide. works better than the 1 to 2 ratio.
The pads are perfectly registered on both sides.
I scanned to post BUT the board turned a ligh silver so there is little contrast. I checked with ohm meter = no conductance.
used a combination of methods to register both sides = came out perfect!!
using PULSAR paper, I used cutePDF to print the top layer and silkscreen mirror the printed the bottom layer w/o mirror.
using expresspcb to design board. it has no provision for mirror
printed layers on plain paper then taped the PULSAR paper to print to save paper.
using the bottom layer (on design, indicate which is top and bottom. I couldn't figure it out so I added then printed) I taped to top of board.
Then drill 3 holes same size as push pins (pc design must have 3 holes "bulls eyes) in 3 corrners.
removed then taped transfer paper to bottom of board (pre-punch bulls eyes holes in paper.have enough area around design so tape doesn't interfere.
insert pins then place, tape the top layer transfer paper using pre-punched bulls eyes holes.
I use a laminator, transfer the image to clean copper.
I run the board through about 6-8 times in different directions.Have yet to lose any traces.
cool then remove paper. inspect paper for non transferred traces. etch board.
drill holes before using liquid tin (mistake tinning then drilling.hard to see pads etc.)Drilling after etching makes a slight crater so center punch is not necessary. I use a 65 drill bit in a drill press.
lightly sand board after drilling as you get nubs on back side. sand before tinning.
apply tin then apply silkscreen using same indexing method with pins.
I use liquid tin in a plastic bag, works good. I get about 4 small boards before it doesn't work as fast.
the etching solution = 1 1/2 parts muratic acid to 2 parts hydrogen peroxide. works better than the 1 to 2 ratio.
The pads are perfectly registered on both sides.
I scanned to post BUT the board turned a ligh silver so there is little contrast. I checked with ohm meter = no conductance.