Homebrew PCBs

>
> I cannot remember the exact numbers but I think 1.2 to 1.3 was
> the range. The problem is your test cell may need to be
> relatively large >500ml in order to fit hydrometer.

i have taylor-made a vertical tank to fit it.
i also have a big test tube where it fits perfectly.

But is can now stay in the tank permanently.

I have choosen to use a "clamp" pcb holder after all,
it is operated with one hand and can hold all pcb thicknesses...


> Brushes are
> made from a copper/graphite composite. The dark color could of
> been the copper forming copper(1+), which as you know is dark.

i think it were the more carbon black brushes, there are some that
are shimmering slightly yellow/red. but you may be right.

> The graphite rods I've used normally just disintegrate into
> course powder and settle to the bottom of the container. If no
> gas is formed then the rods should in theory last forever.

well i guess the carbon power should not disturb the etching process at 
all?

have to leave now....

ST