Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

On Sat, 23 Feb 2008 09:51:05 -0000, you wrote:

One method that is recommended by pulsar (who makes TT paper).

1) take the DS board and prepare one side. Toner transfer to it.
Registration is not a problem yet.

2) cut a piece of self adhesive shelf paper (Kmart: Martha Stewart)
and fasten it to the unprocessed side.

3) etch the board as usual. You should get a one sided board with
bare (and protected) copper on the other side.

4) remove the backing, do not yet tin coat the board if you do this.

5) at this point, I then drill a few well chosen holes in the board,
and matching holes in the paper.

6) prepare the board and align the second side with the holes in the
first.

7) run the board through the laminator again. You can use thin paper
to protect the other side's toner

8) put a layer of contact paper (I use transparent so I can see what's
happening) on the etched side.

9) etch the board if the registration is OK. I'd put in a pattern to
make sure of that.

10) remove the backing, and the used toner. Tin plate as needed.

11) trim the board and drill as required.

Comments:

1) this is a lot of steps

2) it's easier to align a pattern with the etched pattern on the other
side of the board than otherwise.

3) less stress on the laminator

4) if you have a problem with both sides etching at different rates,
this solves it.

5) you can strip the second side and reposition it if you must, since
the first side is aligned by definition.

6) if something goes wrong on the first side, you have not wasted more
etchant and toner transfer paper.

Evaluation:

seems to work so far, but I'm still getting the hang of it.

Harvey



>Hi,
>
>I'm new to this group and joined to learn other (hopefully cheaper)
>methods of producing pcb's.
>
>Many thanks indeed to everyone for the infomation available on this
>group that has enabled me to at least start producing excellent
>single sided pcb's using the TT method and laminator
>
>I was using photoresist with pre-coated boards until recently but
>this has become an expensive option these days.
>
>I have a laminator (Fellowes Saturn A4) and HP laserjet 1200 printer.
>
>The pcb I want to make measures 8.3" x 4.2" and also double sided.
>
>Following the instructions found on the messages for the procedure, I
>managed to produce a good single sided toner transfer pcb of the
>above size using pages removed from an old Toolstation catalogue and
>8 passes through the laminator. The pcb quality was as good as the
>photoresist method, which is very pleasing.
>
>The only difficulty I had was that the paper tended to crinkle during
>the first couple of passes through the laminator rollers (earlier
>attempts whilst locating a suitable paper for the TT method was
>performed on much smaller boards and this problem didn't occur) The
>answer seemed to be to place a sheet of plain copier type paper on
>top of the TT paper for the first few passes until the TT paper stuck
>solidly down.
>
>Although the laminator accepts a pcb + the thin TT paper quite
>happily, adding yet another, further, paper layer on top of the TT
>paper is causing the machine the stress itself. This sort of rules
>out any attempt to perform a simultaneous action on both pcb sides at
>the same time.
>
>Does anyone know a method to achieve double sided boards using
>preprinted mag/cat paper to make double sided pcb's?
>
>Regards,
>
>Steve (GW4ZDU)