KPR should last your lifetime as long as it is kept in the tightly sealed
brown glass bottle it came in. The stuff should smell something like
fingernail polish. The early developers were/are nasty chemicals.
Carcinogens and the like. I used to use trichlorethelyene 1.1.1 and it
worked great! YOu just could not breathe any vapors. Illegal to purchase
now. I used it in 5 gallon drums to clean hydraulic oil from the floors of
nuclear missile sites underground. Not very much ventilation. We'd come out
after a day of breathing tons of that stuff as high as a kite. Little did we
know our kidneys and liver were being damaged.

Xylene is currently available to use on circuit boards. Go to my new web
page and I explain the whole thing. http://www.pic101.com/pcb

My boards are so consistent I never had to use a dye.

Rick

Alan Shinn wrote:

> Wow,
> I was recently looking at my ancient bottle of KPR and was wondering if
> it still works. Do you use the developer that was sold to work with it
> or have you found a substitute?
> I used it long ago to photoetch brass jewelry. I used one of thos little
> spray thingies with it. Then there was some nasty seeming developer
> stuff (some sort of chlorinated hydrocarbon) which I no longer have.
> Then there was a nice dye to put on after developing (dissolving off the
> unexposed resist) to be able to see the remaining resist to "proof read
> it". The system worked very well for me but it did take a bit of doing
> to learn how.
>

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