On 14/02/2013 14:34, Mitch Davis wrote:
> On Fri, Feb 15, 2013 at 12:32 AM, Leon Heller leon355@...
> <mailto:leon355%40btinternet.com>> wrote:
> >
> > Photo-resist goes off after a few months, which could cause a problem
> > with old stock.
>
> When making PCBs at home, I use Kinsten pre-sensitised board. I
> haven't had a problem with photoresist going off, because I seal the
> bag tight after I've cut off as much as I need, and store it in a
> lightproof box. I haven't had luck with developer though. It seems
> that once it's made up into a liquid, it doesn't keep for more than a
> few weeks.
The NaOH developer I use (2 tsps per litre) lasts indefinitely.
Leon
--
Leon Heller
G1HSM