Homebrew PCBs

> dave wrote:
>
> I am using UV exposure method on clear acetate
> 15 secs exposure caustic soda developer about
> a 60 secs

As other have said, if you have not done a test
strip you should.

Is it positive or negative acting and what brand
photopolymer?

Most of them recommend stripping in lye and
developing in sodium silicate or sodium
carbonate.

 
> hydrochloric acid / peroxide etchant no bubbler
> just sloshing about but the problem is the
> protective layer is coming off after a few
> minuets of etching
> 
> hydrochloric is 30%
> peroxide is 9%
> 
> Any advice please

It's probably nothing to do with the etchant.

Most likely under exposed if it is negative
acting resist.  Negative resist can be hard
on top and soft underneath.

Could be the sodium hydroxide soaking in and
continuing to weaken if it is positive resist.
Acid/stopbath it or switch to sodium silicate.

All this is assuming that the boards are pre
coated professionally and not being coated
or laminated by yourself.  If you are doing
the lamination by yourself there are a whole
range of other problems it could be.