When I was doing my dual side PCBs at home (70’s and early 80’s),
I always used two single side 0.031” copper clad FR4 that I etched while single sided.
I drilled the registration holes (3 in a different corner), then I glued (two part epoxy)
the two single side PCBs using the three pins to align the boards properly, then I
secured the two boards with two pieces of plywood and two C-clamps, then waiting for
the glue to cure in a warm oven to speed up the curing.
When the glue was cured, I drilled all the holes, and installed the eyelets using a
small harbor press with the proper punch and die.
The top side was the eyelet collar and the other side (tube) was broken in four parts
by the punch, so proper soldering was easy and very reliable.
I never had a failure of these eyelets.
Just my $0.02,
Jean-Paul
N1JPL
> On Mar 19, 2016, at 3:27 PM, Harvey White madyn@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
>
> On Sat, 19 Mar 2016 10:31:19 -0700, you wrote:
>
> >Ancel,
> >
> >Thanks for the link. He has some interesting approaches. I was with him
> >all the way until the Nitric Acid. Bad stuff in any concentration.
> >Luckily, this works with our more conventional etchants.
> >
> >My issues with double sided are not registration, I use similar pins,
> >but mine are the ones with the metal tops. I found those to be more
> >uniform in diameter from one pin to the next.
>
> I should probably get some drill rod and make a fixture.
>
> >My problem has always
> >been getting uniform etching on both sides. At one point, I built a
> >vertical bubble etcher with a heater for ferric chloride etching. I
> >arranged the bubbler such that I had coverage on both sides. The
> >results was that the edge of the board closest to the bubbler became
> >over etched, while the area furthest away was only beginning to etch.
>
> Exactly what happens. I ended up monitoring the process and moving
> the boards around. Since I do one side only, it's easier to monitor.
> I've also been known to turn the boards upside down. It will make a
> difference, but it's not a hands-free process.
>
> I use HCL and peroxide, and that works well enough. I would like to
> use sodium persulphate, and I actually found a flow tank (two aquarium
> pumps and shaped plastic) to use with that etchant, but I am quite
> wary about using it with anything with acid in it. It has a heater as
> well.
>
> >I envied the spray etchers my company used in their PWB production area.
>
> Love to have one, there are some construction articles around, though.
>
> >My best results were obtained by fully masking off one side while
> >etching the other. Tedious, but it works.
>
> it certainly does. The epoxy board method makes the process somewhat
> more manageable.
>
> Harvey
>
> >
> >(Another) Harvey
> >
> >On 3/19/2016 2:12 AM, AncelB mosaicmerc@... [Homebrew_PCBs] wrote:
> >>
> >> You may find this useful:
> >> https://hackaday.io/project/7938-pcb-smt-maker-lab-home
> >>
> >> I do single pass toner transfer -double sided with good registration
> >> permitting a single etch .
> >> Ancel
> >>
> >>
>
>
>