Homebrew PCBs

Andrew wrote:
> 
> 
>  > Adam wrote:
>  > <SNIP>
>  > I use alkaline ammonia chloride etchant because
>  > I etch with electroplated tin as the etch
>  > resists, and all acid etchants attack tin.
>  > This etchant is very rare among hobbyists
>  > because it really needs spray etcher or sealed
>  > chamber to operate due to ammonia fumes. It
>  > also needs complicated chemical analysis to
>  > make sure it stays working.
>  >
> 
> Adam, have you dropped the CuCl in favour of
> the alkaline etchant because of problems with
> through hole plating ?
> 
> Is the whole tent and etch thing problematic?
> 
Andrew, thats right. I gave up on tent and etch because there were 
always a few holes which failed to seal properly thus destroying the 
plating during etch. Unless the pads has sufficient hole coverage and 
your hole drilling accuracy to spot on, then the tent method can be 
unreliable.  But don't get me wrong, pattern plating has its own set of 
problems too. It is a little more work adding the tin step and dealing 
with ammonia etchants, but I think the results are more reliable. The 
ammonia chloride etchant is very fast too compared to aerated CuCl. I 
run it at ambient temp which is 5~6\ufffdC this time of the year and still 
works ok for me.