I do not know if this is a good procedure or not, but you can read it on Maplin's site: Single and double-sided copper clad SRBP and glass fibre boards coated with a positive photo-resist suitable for use with our UV exposure box. The boards are covered with light proof protective film, which should not be removed until the board is used. The PCB should be exposed using our UV exposure box and a circuit overlay transparency. Exposure time will be from 8 to 15 minutes. Mix together 0.5l approx with one teaspoonful of sodium hydroxide (available from most chemists) and pour into a tray (CH38R). Gently rock the exposed PCB in the tray until the unwanted photo resist is dissolved away. Etch the board in a bath of ferric chloride and after rinsing, expose the PCB in the UV box for a further 10 minutes. Wash of all the remaining etch resist in a tray of sodium hydroxide solution. On 26/09/06, Mike Harrison wrote: > > On Tue, 26 Sep 2006 14:40:57 +0800, you wrote: > > >how do you cut presensitised boards without exposing them... > > Guillotine or jigsaw/hacksaw. Boards come with stick-on lightproof film. > > >> Ive got line width as thin as 15mil in ultiboard.. will this method be > >>> able > >>> to etch that thicness in the PCB... Or is there a better lowcost > method.. > >> > >> Painful... difficult enough to make toner stick to a glossy surface in > >> the first place. > >> Expect a lot of touch-up. > > With the UV photo method & decent board material, linewidths & spacing of > 10mil are easily > achievable. > > >>> can ordinary inkjet be used instead of a toner from a photocopier.. I > >>> printed an image using HP inkjet(reffiled cartridge not the real hp > ink) > >>> on > >>> a transparency film and put it on a ferric chloride solution for over > a > >>> day > >>> now and it does not seem to dissolve.. although I have not tried to > etch > >>> anything from it, I was wondering if it could be used and if anybody > here > >>> tried it... > > The copper should turn pink instantly on contact with ferric chloride. If > it doesn't there is still > resist there. > > > >> Inkjet printer, inkjet overhead projector slide, small UV tube > > Tracing papaer works better than OHP slides, especially on a laser > printer. Better opacity & > adhesion, & cheaper. Results are variable on inkjets from what I've heard. > > > For tons of info on making good homemade PCBs, see my page : > www.electricstuff.co.uk/pcbs.html > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- unPIC -- The PIC Disassembler http://unpic.sourceforge.net -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist