Homebrew PCBs

Hi Stefan,
I had been using 3M 33+ because it is very stretchy compared to other
electrical tapes, and it conforms well. I have been running my
fingernail along the overlap.  Based on your comment, I'll look for
some thinner tape.

I have to use so much heat with the Brother toner, it re-transfers off
the copper to the paper towel or whatever I use under the board if I
do both sides before etching.  I wonder what wax paper would do? Wax
might act as a resist, though. Something Teflon coated, maybe.

As to the heat, I've been using a piece of ceiling tile between my
iron and the paper towels and the plywood bench I've coated with
sanding sealer.  The heat is so great that the tile transfers through
the tile to the plywood finish!  I glued some construction paper to
the tile as a backing with 3M super adhesive (contact cement), and the
cement melted and transferred.  I think I need to use space shuttle
tiles, or aerogel, or something as a work surface :)  Actually, bare
plywood would be better, I think, since it's not flammable.  I'll put
a couple of bricks under a piece and try that.

Regards,
Ted
--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@...> wrote:
>
> On Sat, 30 Sep 2006 16:42:49 +0200, kilocycles <kilocycles@...>  
> wrote:
> 
> >  One
> > problem, yet unsolved, which was not part of the test, is performance
> > of tape when it has to overlap for coverage.  I've been getting some
> > seepage  under the overlaps at the edge of the boards using 3M 33+
> > electrical tape.
> 
> 
> I found the problem goes away if i rub the overlap with a fingernail
to  
> close it up. I used thin PE or PP tape.
> 
> Best seems to be to avoiding to mask stuff at all, simply etch both
sides  
> at once.
> 
> ST
---snip--