Homebrew PCBs

> It's a good idea to use the pre-coated PCB material fairly soon after
buying
> it, as the shelf-life is limited. I find I get rather poor results when
> using stock much older than about six months. I tend to accumulate a lot
of
> odd-sized pieces of unknown vintage, so I need some sort of FIFO
technique.

Leon,
Evidently it depends upon the chemical used to coat the boards. There are
different chemicals and I cannot tell you what they are. However, I have
always had a good quantity of stock on hand and when I stopped running the
business, this caused me to have a lot of board stock that has been sitting
in my bin. I am now using stock that I purchased more than two years ago and
I am not seeing any differences in the way it etches or develops. All I can
tell you about the material is that it is the green coating and that I had
the stock with the red tinted coating in the past and it did not last very
long like what you have described.
-Mike