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Subject: Re: [Homebrew_PCBs] DLP Double Sided Update

From: Harvey White <madyn@...>
Date: 2014-08-26

On 26 Aug 2014 11:14:20 -0700, you wrote:

>Hi Mark,
>First of all I want to say thanks to You and Stefan for pioneering work for DIY prototypes.
>
>I love your processes, development, and sharing of knowledge.
>
>For multilayer boards, I've always been an advocate of printing single-sided thin
>PCBs and layering them up as needed. On Ebay you can get the material in 5mil, 8mil and 10mil
> and if only double sided material, you can use the extra side as planes and isolate route or etch them
>in an extra step. If my stackup is to thin, say for only 2 sides, I found bare FR4 that I use as a base
>to bind the sides to for stiffness.
>
>Alignment fudicials or targets are used for each pattern. Then after etching, I drill fine holes
>through which I insert sewing needles or music wire to align during the stackup.
>
>I was using 3M spray adhesive, but it can be unforgiving of misalignment. Someone mentioned a slower thin epoxy solution and that made sense for me. You just have to remove any epoxy 'extrusions' that occur from the holes.

Put a layer of masking tape over the boards when you epoxy them
together, and that keeps epoxy fingerprints from getting all over the
board. I use a "blue" tape simply because the adhesive is less
aggressive, and it's easier to get off.

Harvey

>
>So for me you process is darn near perfect, the added stability you propose is surely a benefit too.
>
>I hope to get some pictures to share of results as time permits.
>
>Best Regards, and sorry if I came across as pompous in the past, I was kidding.
>Lee Studley
>
> R. Lee Studley Senior Hardware / Software Engineer
>Innovative Control Systems, Inc. (ICS)
>10801 N. 24th Ave. Suite 103
>Phoenix, AZ 85029
>
>602-861-6984 Main Line
>602-588-9440 FAX
>
>www.icsaero.com http://www.icsaero.com/