Homebrew PCBs

On Tue, 28 Jun 2005 13:57:56 +0200, Adam Seychell  
<a_seychell@...> wrote:

>
> If tools are corroding several meters away then it must be HCl gas,
> rather than splashes or wouldn't travel so far. What etchant are you
> running ? There should be almost no oder from a open jar of etchant at
> room temp. Keep HCl concentration under 2 Molar. If your stuck with a
> fuming etchant,(i.e an open container of etchant will corrode steel in
> its vicinity) then you have to keep it sealed. All I can recommend is
> keep the place well ventilated during etching, and seal air tight when
> not in use. You must of course also eliminate exterior splashes due to
> bubbles.


I use CuCl, but maybe my fumes fear needs explaining:

Years ago, when i still used HCl H2O2 Tray etching with way too high  
concentrations of all, i forgot a small etchant tray on a workbench with a  
nice new set of drills (and other stuff) about half a meter away. After  
several days (maybe even weeks) when i discovered the situation the drills  
did not look new any more :-(.

This was a open tray, and i haven't discovered problems with my etcher  
(rubber seal, but not really airtight just a lid) so far. There is no odor  
with the current etcher when it is just standing around, but when the pump  
is pumping like 100l/h of air through those 100l will have some fumes in  
them and will definitely leave the etcher.

On another occassion i discovered it is not good to store steel spray cans  
near a closed PE bottle of HCl, the can seam started rusting. This was  
after months.


I will put a few experimental nails around the etcher, and try to put all  
tools further away, then it will be fine to run open-loop i hope. When any  
of the nails start to rust i must do something.

thanks

ST