>
> If you do have any HCl in your etchant, you can easily nutralise it with
sodium
> carbonate or bicarbonate - cheap and very easy to get. You will get bubbles
> forming until all the HCl is nutralised. When it stops bubbling you're done.
> This obviates the need for indicator paper.
>

Let me clarify:
You add sodium bicarbonate to HCl and it starts to bubble. After a while it
stops. At this stage it may NOT be neutralised. You must add a little more
bicarb. If the mix starts to bubble again, wait until it stops and then add a
little more. Repeat the process until adding more bicarb produces NO bubbles. At
this point you have neutralised the HCl.

Be careful when you add the bicarb. Add only small quantities at a time since
the reaction can be vigorous and cause the mix to bubble up over the top of your
container onto your work surface. Also you may get lots of tiny bubbles which
may cause tiny drops of mix to "spray" out of your container onto your work
surface.

Regards
Sergio Masci

http://www.xcprod.com/titan/XCSB - optimising PIC compiler


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