On Wed, 22 Feb 2012 05:03:07 -0000, you wrote:
>--- In Homebrew_PCBs@yahoogroups.com, Harvey White <madyn@...> wrote:
>>
>> On Wed, 22 Feb 2012 02:27:45 -0000, you wrote:
>>
>> >Recently I had my first try at a UV-exposed board
>> >
>> >(because I have nightmares from trying to align paper properly for a double-sided board with the laminator, ha ha)
>> >
>>
>> I figured that one out, or at least, got it very close to right.
>>
>> use half thickness board, prepare each side individually. Make sure
>> that there are three alignment holes, each at a corner, leaving out
>> one corner (keeps the board from being reversed).
>>
>> I use map push pins and a slightly smaller drill. You want a thick
>> pin so it does not get pushed side to side by misalignment.
>>
>> Harvey
>
>Why half-thickness board? How do you get the board into a laminator with push-pins in it? I am not sure I understand how this would work, can you please explain?
Half thickness board: I can get 0.023 board, which will get to 0.46
board when made double sided, which is stiff enough. If I make a
double sided board that has to be 0.063, I use a different method,
detailed in some other posts, (double sided board, one side at a time,
protect the inactive side).
making double sided boards:
The boards are treated completely like single sided boards. The
material is single sided.
Make and etch the boards.
Do not drill anything but the registration holes.
Do not trim the boards.
put masking tape over the surface with the exception of the
registration holes, this keeps epoxy off the surface if it "leaks".
Using 1 hour setup epoxy (trust me, same eventual to full strength
time, and that's what you want anyway), put epoxy on one board.
Put the other board on top and align using the registration holes. Put
some tape to keep the boards in alignment with the pins in.
Remove the pins.
Place between two heavy and flat objects. I use ceramic floor tiles.
Put weight on top of that to keep the boards flat while curing.
Leave for 24 hours (or so).
Remove tape, trim, drill as needed.
Harvey
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