Homebrew PCBs

These are some good notes. Although I like to add one helpful technique 
I found developing boards. Since measuring and weighing out NaOH can be 
a little messy, I found less time consuming to make up a concentrated 
stock solution of say 100 or 200 g/L and then you only need to use some 
plastic kitchenware measuring items to makeup the required 10g/l 
developer solution. The fact that CO2 permeates plastic bottles causing 
NaOH to be slowly converted into Na2CO3 is not a problem with the 
accuracy we are dealing with, unless we are talking decade old solutions 
:).

Adam

caveteursus wrote:

>a 1% solution of NaOH (10 grams per liter) develops a board in less 
>than a minute -- I find it helpful to develop under a red darkroom 
>lamp (yes, I do BW developing as a sideline).  I use 2 glass baking 
>trays one for the sodium hydroxide solution and one for water.  The 
>red lamp is on all the time.  I periodically switch on a "white" lamp 
>to examine the board.  
>
>Caution with Sodium Hydroxide -- over time the pellets (or granules) 
>will absorb water -- as you open and close the bottle in which they 
>are contained -- the moistened pellets will stick to your skin and 
>cause blistering -- so latex gloves are a good idea.  I use filter 
>paper to weigh out the sodium hydroxide and find that over time the 
>little beads of NaOH will also stick to the filter paper -- not a 
>good idea to "flick" them off since they then go everywhere.  
>
>Drano is mostly NaOH, but there's a lot of impurities in it.
>
>
>
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