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Equipment/PCB etch station: Difference between revisions

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==Status==
==Status==
Developer, FeCl3 etch and stripper tanks working.
1st (developer) and 3rd (stripper) tanks working.  
Tinning tank now contains CuCl2 etchant.


I have done a brief test with the CuCl2 etch - it seemed slower than the FeCL3 but I was only agitating it occasionally. It sped up hugely at the end when I agitated it continously - but this might have been because the last bits of copper are thin and suddenly go. If you use it, don't rely on the small bubbler to provide agitation - keep it moving the whole time (and be careful your board doesn't walk out the end of the basket when you do that). The small bubbler is really only there to re-aerate the solution after use, as it's quiet enough to leave on.  
2nd tank contains clean water, checking for leaks before refilling with etchant.
 
4th tank now contains CuCl2 etchant at ~3M strength. Ready to use.
 
If you use it, don't rely on the small bubbler to provide agitation - keep it moving the whole time (and be careful your board doesn't walk out the end of the basket when you do that). The small bubbler is really only there to re-aerate the solution after use, as it's quiet enough to leave on.  




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The bath for [[Project:PCB Making/Cupric_chloride_etchant|Cupric Chloride etch]] is being prepared in the tinning tank using the slow method : leave some copper in acid, allow corrosion to occur generating some oxides, add further copper and acid as required. Water, acid, copper and hydrogen peroxide (if used) should be noted as it's easy to over-dilute if you just add stuff randomly.  
The bath for [[Project:PCB Making/Cupric_chloride_etchant|Cupric Chloride etch]] is being prepared in the tinning tank using the slow method : leave some copper in acid, allow corrosion to occur generating some oxides, add further copper and acid as required. Water, acid, copper and hydrogen peroxide (if used) should be noted as it's easy to over-dilute if you just add stuff randomly.  


The preparation so far contains 540g copper, 2900ml 38% HCl, 1750ml water. SG is 1260. This is close to completion - air has been bubbled through it and it has reached the bright green colour indicating it has converted copper to cupric chloride. The acid concentration appears to be correct and I have reconnected the heater. It may be used for etching, but there is no large air bubbler in the tank so may need to be agitated by hand (jiggle the basket containing your PCB). If the etchant is not bright green, please leave the small fishtank bubbler running. The bubbles will regenerate the etchant.
The preparation so far contains 540g copper, 2900ml 38% HCl, 1750ml water. SG is 1260. This is ready for use - air has been bubbled through it and it has reached the bright green colour indicating it has converted copper to cupric chloride. The acid concentration appears to be correct and I have reconnected the heater. It may be used for etching, but there is no large air bubbler in the tank so may need to be agitated by hand (jiggle the basket containing your PCB). If the etchant is not bright green, please leave the small fishtank bubbler running. The bubbles will regenerate the etchant.


DO NOT ETCH ANYTHING EXCEPT COPPER IN THIS TANK
DO NOT ETCH ANYTHING EXCEPT COPPER IN THIS TANK


See [[File:CuCl.pdf]] for maintenance instructions. These are basically : Check colour. Bubble if dark. Titrate against 0.1 molar NaOH to check acid concentration (this only requires a check for precipitate, no need for acid indicator). Add HCl if necessary.
See [[File:CuCl.pdf]] for maintenance instructions. These are basically : Check colour. Bubble if dark. Titrate against 1 molar NaOH to check acid concentration (this only requires a check for precipitate, no need for acid indicator). Add HCl if necessary.  


===Usage configuration===
===Usage configuration===
* Since it's already stained there's no problem in putting ferric chloride in it if we have some available (it needs 5 litres but 3 or 4 would do).
Planning to change to use CuCl2 in the bubble etch tank. Do NOT mix this with Ferric Chloride. In fact, please don't use ferric chloride at all - it silts up the tank and is really difficult to clean up. If there is some reason why we wish to use it again, it may be possible to use the 4th tank for it.
* We can use a spare tank to start brewing the cupric chloride if we want to do that


===Placement===
===Placement===
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