Homebrew_PCBs

maybe mineral oil. thats not so volatile.

--- In Homebrew_PCBs@yahoogroups.com, "Steve" <alienrelics@y...>
wrote:

> --- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...>

wrote:

> > It seems there are two bondings going on here: toner to paper

and

> > toner to board. The goal is to increase the ratio of bonding to

the

> > board vs bonding to the paper so the paper will release. Of

course

> > there needs to be a minimum level of bonding to the board.

coated

> > paper works because the toner only bonds to the board-side layer

and

> > soaking causes the layers to seperate.
> >
> > The starch method of decreasing paper bonding is very promising

but

> > I've not been able to get smooth enough paper to feed cleanly.

My

> > best effort got creases and spacial distortion of the transfer
> > pattern. I'm skeptical of this working well for 8 mil traces and
> > tqfp packages. I've got some 90 lb paper that might maintain its
> > integrity during starch treatment and will give it a try. There

may

> > be other products that don't wet the paper but decrease the paper-
> > toner bonding. a very thin coating of a light oil (wd40 springs

to

> > mind) might do it.
>
> Yes, as has been covered here in depth, paper contraction due to the
> heat of a laser printer/copier causes problems. I'd imagine a sheet

of

> paper wetted and not sufficiently dried is going to be worse.
>
> I think your analysis of bonding is correct.
>
> As for WD-40, speaking as an electronics tech: Don't do it! WD-40

and

> electronics do -not- mix. WD-40 is -not- an oil. It's volatile,

which

> means heat is going to cause it to evaporate anyway. It's main use

is

> as a water displacer. My father destroyed the hinges on a truck of
> mine, because unknown to me he was spraying all the hinges on my

truck

> with WD-40 every time I visited. I couldn't figure out why my doors
> kept squeeking and sticking, I'd grease them, and in a short time
> they'd stick again. He'd hosed out all the grease with WD-40 and
> within a short time all the WD-40 had evaporated, leaving nothing

but

> metal to metal contact with some dust thrown in.
>
> I suspect coatings are the answer. I tried inkjet transparencies, on
> the theory that the coating on the plastic is water soluble and so
> would easily let go of the toner when soaked. I was right, the
> transparency got slimy when wet and let go easily. The problem was I
> could not get water all the way under the plastic and the toner

stuck

> better to dry inkjet transparency than it did to copper.
>
> And as has been pointed out here, the plastic caused the traces to

all

> mash out.
>
> Steve