Homebrew PCBs

Sorry about the confusing replies, I've not used this system in a while 
(apart from my previous post)
It is unlikely that it is the PCB shrinking on cooling, more likely the 
paper, to heat a pcb enough to cause several mm of expansion would 
probably carbonise the toner and paper.
As for preparation, I used to think that the PCB had to be clean and 
polished but this process seems more like plastering where you give the 
wall (or PCB) a good key for the toner to adhere to...think of it like 
this, paper is fibrous, photo paper usually has some form of 
powdery/plasticy texture. If the PCB has a better surface finish (ie 
more polished) then in all likelyhood, the toner will remain adhered to 
the paper coating rather than the PCB. If you can, try using a clean 
scrubby texture - non soap impregnated type and scrub the surface of 
the copper to leave fine marks, I used circular motion with plain water 
and dry it using lint free cloths (I used kitchen paper which doesn't 
break down easily with water). I also did not iron the paper directly 
but used another peice of paper in between. It allowed the iron to move 
over the the pcb.

One thing to note is that I tried this process using text rather than a 
circuit (just a page from a report that I wrote). I inspected the 
lettering which had fine detail (e's, 8's).

PK

--- In Homebrew_PCBs@yahoogroups.com, Lez <lez.briddon@...> wrote:
>
> Last night I tried kodak gloss for TT with an old hp5l, copper was
> cleaned and polished, not very successful, it 'lifted' as the board
> cooled, no doubt as the board cooled and contracted a mm or so after
> the heat
> Where it stuck it was stuck, and quite thick, but it also had a lot > 
of the papers gloss topcoat betwen tracks which had to removed 
> carefully, and in fine areas was near impossible.
> 
> Will try tonight with a longer press and less heat.
> 
> I dont want to use 'store brand' papers as a store will often change
> sources monthly to get the best profit margin..........
> 
> I may buy some HP next if I can find it on a good offer.