On Wed, 24 Dec 2003 12:40:09 -0000, Leon Heller <
leon_heller@...>
wrote:
>
> ----- Original Message ----- From: "Stefan Trethan"
> <stefan_trethan@...>
> To: <homebrew_pcbs@yahoogroups.com>
> Sent: Wednesday, December 24, 2003 12:26 PM
> Subject: [Homebrew_PCBs] horiziontal / vertical etching, how to make a
> sealing lid
>
>
>> Hi!
>>
>> I'm thinking about my etch tank.
>> Even if i make a vertical tank how can i make a airtight lid?
>> I want to keep the etchant in and prevent too much corrosion.
>>
>> The lid shoud keep all gases in.
>> it should have a overpressure valve (because of decomposing H2O2, that
>> is
>> no problem).
>>
>> Additionally it should prevent spattering.
>> (when the tiny bubbles (from the h2o2) burst there is etchant splattered
>> out of the tank.)
>
> Some industrial cleaning tanks have plastic beads floating on the top of
> the
> liquid. That might be all you need - they will prevent splattering and
> cut
> down evaporation. You can just lower the PCB through the beads.
>
> Leon
> --
> Leon Heller, G1HSM
Thank you for the information but i'm not very fond of the idea.
It isn't really preventing evaporation totally (i forgot a tray beside some
drills and had to
brush and oil them afterwards - don't like that again.)
And i think there wil always be beads sticking to the pcb/holder and so
on...
I would rather like to have this thing closed well.
(i now store the etchant in a glass bottle with a pinhole in the lid for
releasing pressure.
it stands close to iron parts and no rust at all for years)
ST