>
> Can I ask why you decided that the lid must be air tight ?
>
> The only possible reason I can see why you may want an air tight seal is
> if your planning on storing concentrated HCl and you don't want the any
> fumes to escape. If you are running HCl+CuCl2+H2O2 mix then the acid
> concentration should not be so high that any significant amounts of HCl
> gas escapes.
> A 5% HCl solution is normally what they run at. Yes, HCl gets consumed
> during etching, but assuming you have relatively large volume of solution
> to the etching copper mass then your HCl additions should not be too
> frequent.
You didn't have to clean my drills did you? ;-)
NoNo, that must be sealed up! i forgot a open jar with my etchant (it is
like you assumed)
on a desk with tooling on it. the drills developed nice red rust which i
had to brush off
and oil them. (i dipped them in weak NaOh to neutralize any acid residue
just to be sure)
>
> To make air tight seal then you must have a flanged tank and a flat
> rubber seal between the flange and lid. Then depending on the thickness
> of the plastic used the lid must be tightly clamped to the flange at
> every 20 mm to 60 mm with screws. This is how I sealed my spray etcher
> chamber, but as Marvin pointed out this is essential when spraying.
>
"airtight" not exactly. tupperware says their containers are "almost
airtight".
that's very fine for me.
The bottle with the 1mm pin hole in the lid isn't causing rusting tools.
(for years).
> I think a partly sealed lid is all you need, just so that evaporation and
> any air flow are restricted. There is a large range of rubber foam strips
> available for door seals. These will make a good seal for a etchant tank
> lid just from the weight of the lid on the foam.
>
I think you are right.
> .... cropped (don't think the rest was bad - just because of the archive
> storage space)
Thank you for your drawing and hints.
I thought of a similar design too.
But i am determined to give the horizontal etch a try.
I will use a tupperware container, and suspend the pcb holder off the lid.
I hope i can soften the lid with the heat gun and depress it in the center.
this would make any condensed drops run together there and drop down.
should be possible, what is tupperware made of? PP?
If it works it would be much less work than welding a complete tank.
(this would take at least a day).
I'm stillthinking about the pcb holder design.
Stefan