Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
> 
> two things,
> 
> first, the component legend is easily freed from paper residue by
abrasive  
> pad (meant for cleaning copper tubing to solder), which i use for
cleaning  
> the copper too. then use a paper towel (use shop-grade recycled
material  
> which is pretty abrasive) and polish it to a shine with a few rubs.
> (could use polishing wheel too.)
> Gives a perfect shiny component legend, similar looking to black  
> silkscreen (actually much better ;-) )
> (Note: previously i used abrasive kitchen cleaner and a lot more
effort to  
> polish it and remove the residue).

I do a hot peel - just pull the paper off when its still hot.  Works
quite well and its a lot faster.  It doesn't leave quite as much toner
but its very legible and no cleaning is needed.


> 
> second, alignment of double sided boards or copper artwork bottom /  
> component legend top in one go:
> I realised the problem with aligning double-sided things was that the  
> paper shifted when fed into the
> fuser no matter how hard i tried to glue/tape it etc.
> I needed a glue to stick the paper directly to the PCB. The obvious
is to  
> use toner!
> i just make a 5mm broad strip of solid toner above the artwork, and
stick  
> it on with a clothes iron.
> Works great. only iron the strip to prevent any bad effects on the
other  
> artwork. Maybe the artwork
> itself could be used to stick it with the iron, and the laminator
only to  
> ensure a uniform adhesion.
> The 5mm strip is not a problem for me because i use it to clamp the
board  
> during etch.

I've not had any problem with tacking the artwork (vs a special toner
strip) before feeding through the laminator.   But, I don't bother
with that anymore - I use a carrier for the board/paper assembly.  I
fold a sheet of children's "construction paper", put the assembly
inside and and feed it through the laminator.  I've had good to great
alignment on about 30 boards I've done (yeah, i really should have
sent them out...).  Its my guess that the paper to paper contact slips
more easily than paper to copper does.  Prior to using a carrier or
tacking I was getting 5-10 mils of mis-registration.  Now I think I'm
getting around 2-3 mils or less which is better than the accuracy of
my drilling.