What to do if started etching a preamp board but some tracks have less than 1mm space between them and b327 is not etching thoose, i see copper left in there, yesterday tried to leave for more time, but no luck etchant started to eat spot where track got broken and i painted a track spot with sharpie.Here you can see the copper in gaps between tracks and pcb on photo paper http://www87.zippyshare.com/v/2VfJkXjz/file.html
Last edited:
For precaution always wear plastic/rubber glove when handling etchant
Make sure sodium per-sulphate etchant be heated to work fast enough (40-45 C). Otherwise severe under etching will happen and not uniform.
if you are using tray, put a larger tray of warm/hot water below it.
To safe this particular PCB, the area that etch slower need to be etched faster, one way is to use swipe on it using sponge/brush repeatedly, the erosion and breaking the surface tension will etch specific areas faster.
another way ( maybe less tedious ) paint/cover the rest of the etched area with sharpie and continue etching.
if those un-etched area is covered by paper fibres, remove the fibres first, otherwise it will not etch properly.
Make sure sodium per-sulphate etchant be heated to work fast enough (40-45 C). Otherwise severe under etching will happen and not uniform.
if you are using tray, put a larger tray of warm/hot water below it.
To safe this particular PCB, the area that etch slower need to be etched faster, one way is to use swipe on it using sponge/brush repeatedly, the erosion and breaking the surface tension will etch specific areas faster.
another way ( maybe less tedious ) paint/cover the rest of the etched area with sharpie and continue etching.
if those un-etched area is covered by paper fibres, remove the fibres first, otherwise it will not etch properly.
As Hartono suggested, agitate the area by brushing lightly or moving the whole solution by moving the tray back and forth to get "fresh" etchant in the area. I have heard of one person etching his boards vertically and using a fish tank bubbler to agitate the solution.
🙂
🙂
I make batches of, say, 40 to 60 PCBs in a large 20 liter tank , and have plastic frames holding PCBs vertically.
Spent copper loaded etchant is denser and falls, fresher etchant naturally replaces it, boards etch smoothly top to bottom without need of mechanical agitation.
Putting an aquarium heater on one tank corner , besides warming etchant also creates convection currents, even if slow they help.
If etching just one or two, I let them float face down on etchant, it takes some skill to avoid trapping an air bubble which would lead to a mystery shiny copper round dot and also not to drop it too hard which woukd sink it, but etching is fast and clean.
Why not just put them in a tray, face up, and shake it back and forth?
Well, that´s fine for hobby use, I am usually busy doing something else while PCBs etch 🙂
Spent copper loaded etchant is denser and falls, fresher etchant naturally replaces it, boards etch smoothly top to bottom without need of mechanical agitation.
Putting an aquarium heater on one tank corner , besides warming etchant also creates convection currents, even if slow they help.
If etching just one or two, I let them float face down on etchant, it takes some skill to avoid trapping an air bubble which would lead to a mystery shiny copper round dot and also not to drop it too hard which woukd sink it, but etching is fast and clean.
Why not just put them in a tray, face up, and shake it back and forth?
Well, that´s fine for hobby use, I am usually busy doing something else while PCBs etch 🙂
- Status
- Not open for further replies.