cheers for the advice I will try another test strip but go over longer time.
The uv box is a converted scanner with four UV 9W tubes from a nail curing unit
The boards are positive photo from Maplins
it is clear acetate lazer printer. I print 2 images to double up the thickness
Dave
--- In Homebrew_PCBs@yahoogroups.com, "smilingcat90254" <smilingcat@...> wrote:
>
> One thing not mentioned so far is to cure the image after exposure-development.
>
> After the image is developed on the board, some recommend to cure the remaining resist by exposing the image to harden the image. Some resist may not be compatible with this step so check first.
>
> Another issue is resist adhesion. Lots of discussion on this too. I always wear rubber glove to keep the board free of oil from my hand and to keep chemicals off my hand. Some even have recommended to mildly pre-etch the blank then apply the resist. And so on...
>
> If you want to be accurate with exposure, you might want to use Stouffer's 21 step exposure guide. do a google search if you want one.
>