Homebrew PCBs

--- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> wrote:
> 
> --- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
> <stefan_trethan@g...> wrote:
> > 
> > On Thu, 11 Nov 2004 14:44:38 -0000, mikezcnc <eemikez@c...> wrote:
> > 
> > >
> > > 4. There was something listed here to remove the laminated toner but
> > > I don't remember what it was. The usual acetone is just too
terrible.
> > > Maybe it was Stefan's suggestion to use a paint thinner?
> > 
> > I don't know why acetone is terrible, but it attacks the epoxy,
> leading to  
> > toner smeared into it.
> > Paint thinner doesn't do that. From a health point of view acetone
> is much  
> > better than paint thinner.
> 
> You know, I don't understand why you are having this problem with
> acetone.  I use it and it leaves no stains on my FR4 material what so
> ever.  I can clean off a botched legend print and go again.  I wonder
> if its an issue with the toner or something in the PCB material.  I
> recall having trouble with a radio shack copper clad board but that
> wasn't FR4 (can't recall what it was).

I think it has to do with the type of board.  I've had this problem
before, too (although it's been a couple of years since I've 
etched any boards).  The acetone seems to melt the toner, and then,
when rubbed, seems to be transported to the board where it soaks in
and refuses to come out.  I've not found that it causes any problems,
other that discolouring the board and making it look not quite as
nice.

> For me, acetone is worth the precautions it takes to be safe
> (ventilation).  It takes the toner off in seconds.  I also use it for
> board prep - it degreases the copper perfectly and leaves no residue.

Don't forget that acetone may also be a liver carcinogen.  It's not
nice to breathe it, or to get it on your skin, since it may be
absorbed through the skin.

Dave