Homebrew PCBs

On Wed, 22 Feb 2012 00:12:34 -0500, you wrote:

>I think Harvey is saying expose, develop, and etch the top board first for
>the top layer.  Then do the same for the second board for the bottom layer.
>Lastly glue/laminate the two boards together.
>
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>
>My question is, what is being used to glue the boards together?  Epoxy,
>repreg?  Any good recommendations for a glue that is easy to spread over a
>whole board, low cost, and available?  Prepreg does not seem to fit the
>available part.  

I use 1 hour epoxy, in the "large" size.  Costs about 15 dollars or
so, you'll get a feeling of how much epoxy to use.  Too thin a coat
and you don't get full adhesion.  You want the 1 hour because doing a
number of boards can take longer than you think.  Same full strength
cure time for all varieties (24 hours).

Use old board trimmings to spread the epoxy, but make sure that you do
not contaminate the "new" epoxy with any old epoxy, apparently cures
much quicker than you thought.  Putting the masking tape on (avoid
transparent scotch tape) avoids epoxy fingerprints on the board.

I've tried:

1) superglue... works, but rather expensive and not as good as I might
like.

2) shorter curing epoxy... cures too quickly, rushed jobs....

have not tried:

1) carpet tape:  hard to position and I'd be worried about the glue
jamming and breaking the carbide bits

2) contact cement:  same as carpet tape.

Harvey

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>From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
>On Behalf Of tda7000
>Sent: Wednesday, February 22, 2012 12:03 AM
>To: Homebrew_PCBs@yahoogroups.com
>Subject: [Homebrew_PCBs] Re: Printers not making pattern opaque enough for
>UV process
>
> 
>
>  
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>--- In Homebrew_PCBs@yahoogroups.com
><mailto:Homebrew_PCBs%40yahoogroups.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?
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