Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Hi all

The new vertical tank is finally in use and i am pretty satisfied with the
handling.
it features a pcb clamp that can acceept all thicknesses, and this clap
can be opened/closed
with the same hand which also holds the lid/holder itself.
I used a plastic rod which is spring loaded and pressed on with the thumb
to open the clamp.
this means i can feed the pcb and also afterwards drop it into the water
tank without ever touching
etchant-exposed parts or washing any part of the pcb holder.
the visibility of the vertical glass tank is also great.


But to my questions:

With CuCl analysis, the initial amount of water does not play a major role
i think?
the instructions call for 5ml of water, then 10 drops of etchant, 1 drop
of indicator,
and then n drops of 1mol NaOH which are the etchant molarity∗10.

Is it necessatry to measure this initial amount of water?
Is it correct that the only important thing is the equal size of
etchant/NaOH drops?

I guess it would also be possible to make a "ready to use"
water/methylorange solution?


The molarity of the etchant i used in the old tank was over 3, so i
diluted it with water
to get 1.5. of course the etching is now terribly slow, because i have
nearly no copper in.
i will dissolve some copper to get the density up (the hygrometer is off
range, 1.6 would be
the lowest value)

Next question is about rubber. i have used a piece of bicycle hose to make
the spring action of
the clamp. will it hold up inside the etchant tank? it is not immersed but
exposed to the fumes all the
time. any experiences?

thanks

ST