Homebrew PCBs

Hans Wedemeyer wrote:
> Russell,
> Well I did a QFP144 which has 0.25mm pads with 0.2 mm spacing between
> the pads, that's the tightest I could find in EAGLE and placed two of
> them connected one to the other with about 1/4 of the pins and printed
> it.
> 
> Results are very good. Clear space between the pins, I can etch this
> size no problem.

I assume you mean very few if any shorts between pads?

> So I made a few 2.5 mil  traces (which I can't etch reliably) and wired
> between the QFP144 pins.... OK that failed, that asking much than this
> laserjet can do, which is 0.005"
> 
> About the clogged Epson, I only ever used the real Epson cartridges, in
> fact I have an unused one here, out of date now...
> 
> Blackness: No the exposure will still eat your lunch, even if you have a
> Litho film the light source will scatter and cause problems.
> Get to know your light source, then blackness is not a problem.

I get sharper results by using spray-on PRP positive resist because the
plastic coating sheet on pre-coated boards causes more undercut with a
close-in uv light source.

> 26 mil is hughes.... Not really for Home Brew PCB making (the theme for
> the forum)  which for the most part "implies" hand soldering MSOP is
> about the smallest I like to do comfortably.
> 
> I still think there has to be a reason so many people are dumping Epson
> Inkjet printers for $5 ! as you are referring to eBay.au I assume
> Australian dollars...

I've seen similar prices on US ebay too. Most users want to print photos
sharper or faster (USB) and new printers are cheap.

> In the final conclusion, I still maintain that for Home Brew PCB making,
> the  LaserJet is cheap to run and does a fine job. Even at AU$5 I would
> not waste time on an Epson printer, the two I trashed cost US$475 at the
> time.... I doubt the print head problem is any better.
> 
> Please continue to use your Epson. Please do NOT spread misinformation
> about LaserJets, form reading your post, one could be believe Espons is
> the ONLY solution, when  the fact is "Average" hobby / homebrew PCB
> maker will never reach the level of a QFP256 pin device. We have people
> here still talking about Iron On transfers.... :-)

I've used laserjets, but the results were hopeless. What model is yours
and how old is it? Genuine toner?