Homebrew PCBs

Totally agree. 15 seconds seems very short. With a bunch of fairly standard UV LEDs my Chinese eBay resist takes about 6-7 minutes to expose well.

I also let it cure in the dark for a few minutes after exposing.

I also do another few minutes under UV and let it cure again after developing, before etching.

I have had the resist come off before in the developer when it was under-developed or the developer was too hot. But if it stands up to that, I have not yet had a problem with it falling off during etching.


--- In Homebrew_PCBs@yahoogroups.com, Paul <paul@...> wrote:
>
> Dave
> 
> It does of course depend on the UV source and the photo board but 15s 
> sounds far too short.
> 
> Using laser printed art work on acetate, with my UV box (2 x 8W tubes) 
> and using pre coated board (usually from Mega Electronics) I need about 
> 3 minutes.
> 
> But as folk have suggested try a test strip.
> 
> http://www.piclist.com/tecHREF/piclist/biketut/chapter3.html#zzee_link_9_1019487419
> 
> Paul
> 
> On 12/05/2013 15:07, dave_donlan wrote:
> >
> > Hi guys
> > I am using UV exposure method on clear acetate
> >
> > 15 secs exposure caustic soda developer about a 60 secs
> >
> > 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
> > Dave
> >
> > 
> >
> > No virus found in this message.
> > Checked by AVG - www.avg.com <http://www.avg.com>
> > Version: 2013.0.2904 / Virus Database: 3162/6317 - Release Date: 05/11/13
> >
> 
> 
> 
> [Non-text portions of this message have been removed]
>