Homebrew PCBs

I have been using the "thinner" .032 PCB blanks for a while now and I have a
love/hate relationship with them.


pros:

* easier to run through my H220 TIA laminator
* easy to cut (this is key)
* easier to drill for through-hole boards and mounts
* lighter

cons:

* a bit flimsy
* can torque and possibly break the boards with little effort


Question to the group:

Is it feasible to use 2 one sided .032 boards and glue them together? Or
even created some sort of 4 sided PCB using glued .032 boards? For the
4-sided boards the vias would need to be plated, but had anyone attempted
this?

This would double the amount of holes you would need to drill out, but I try
to stay in the SMD world nowadays.


The challenge, it seems to me, would be the alignment of the via and part
holes.

Currently, I hold the board up to the desk light for alignment, but this
would not work if you had 2 pcbs. Maybe I could cut both pcbs about the same
size with my paper cutter (close to the exact same size, but it wouldn't be
perfect), then make each board, centering the pcb image as close as I can.
Then, drill the pcbs, and then apply glue and simply line up the holes using
the desk lamp. Then carefully sand down the edges until the entire edge is
flush.

Am I crazy or is this possible?

It seems to me that we all would prefer to work with thinner boards, but a
have thicker board as a finished product?


thanks!
Chris


[Non-text portions of this message have been removed]

I have some of the super-thin 0.01 boards and have been thinking the same
thing. My colleague told me they are laminated together for thicker boards,
so I thought I might try it as well. I was thinking I would etch two boards
and epoxy them together, copper sides out, probably squeeze the whole thing
between some pieces of wood in the vice. Then use pieces of ribbon cable
soldered at the edges for a cheap easy "via", 16 lines at a time.

On Tue, Jun 7, 2011 at 8:02 AM, Chris Kleeschulte <laconia@...> wrote:

>
>
> I have been using the "thinner" .032 PCB blanks for a while now and I have
> a
> love/hate relationship with them.
>
> pros:
>
> * easier to run through my H220 TIA laminator
> * easy to cut (this is key)
> * easier to drill for through-hole boards and mounts
> * lighter
>
> cons:
>
> * a bit flimsy
> * can torque and possibly break the boards with little effort
>
> Question to the group:
>
> Is it feasible to use 2 one sided .032 boards and glue them together? Or
> even created some sort of 4 sided PCB using glued .032 boards? For the
> 4-sided boards the vias would need to be plated, but had anyone attempted
> this?
>
> This would double the amount of holes you would need to drill out, but I
> try
> to stay in the SMD world nowadays.
>
> The challenge, it seems to me, would be the alignment of the via and part
> holes.
>
> Currently, I hold the board up to the desk light for alignment, but this
> would not work if you had 2 pcbs. Maybe I could cut both pcbs about the
> same
> size with my paper cutter (close to the exact same size, but it wouldn't be
> perfect), then make each board, centering the pcb image as close as I can.
> Then, drill the pcbs, and then apply glue and simply line up the holes
> using
> the desk lamp. Then carefully sand down the edges until the entire edge is
> flush.
>
> Am I crazy or is this possible?
>
> It seems to me that we all would prefer to work with thinner boards, but a
> have thicker board as a finished product?
>
> thanks!
> Chris
>
> [Non-text portions of this message have been removed]
>
>  
>


[Non-text portions of this message have been removed]

DJ Delorie has made a 4-layer board this way. Search on his name on this site -- or maybe he'll chime in.

--- In Homebrew_PCBs@yahoogroups.com, Chris Kleeschulte <laconia@...> wrote:

>
> I have been using the "thinner" .032 PCB blanks for a while now and I have a
> love/hate relationship with them.
> 
> 
> pros:
> 
> * easier to run through my H220 TIA laminator
> * easy to cut (this is key)
> * easier to drill for through-hole boards and mounts
> * lighter
> 
> cons:
> 
> * a bit flimsy
> * can torque and possibly break the boards with little effort
> 
> 
> Question to the group:
> 
> Is it feasible to use 2 one sided .032 boards and glue them together? Or
> even created some sort of 4 sided PCB using glued .032 boards? For the
> 4-sided boards the vias would need to be plated, but had anyone attempted
> this?
> 
> This would double the amount of holes you would need to drill out, but I try
> to stay in the SMD world nowadays.
> 
> 
> The challenge, it seems to me, would be the alignment of the via and part
> holes.
> 
> Currently, I hold the board up to the desk light for alignment, but this
> would not work if you had 2 pcbs. Maybe I could cut both pcbs about the same
> size with my paper cutter (close to the exact same size, but it wouldn't be
> perfect), then make each board, centering the pcb image as close as I can.
> Then, drill the pcbs, and then apply glue and simply line up the holes using
> the desk lamp. Then carefully sand down the edges until the entire edge is
> flush.
> 
> Am I crazy or is this possible?
> 
> It seems to me that we all would prefer to work with thinner boards, but a
> have thicker board as a finished product?
> 
> 
> thanks!
> Chris
> 
> 
> [Non-text portions of this message have been removed]
>

You want 3M double-sided film, er, # 7935 laminating adhesive.  However,
this results in boards that are *more* flexible, not less.  Epoxy is
better, but you need a way to hold the boards aligned *and* compress
them together while the epoxy cures.

To stick the boards together, I drill out two matching vias on each
board, in opposite corners, and thread brass wire through them.  That
way they "just line up" when you press them together.  er, you have to
stick the tape to one of the boards first, so you drill out the tape
too.  Then peel the other protective film off and stick them together.

For 4-layer boards, you want really thin outer layers (I use 5 mil) and
16-32 mil or so inner (two 16SS or one 32DS).  To solder to the inner
layers, you need to pre-drill the outer layers with even larger holes,
so the inner layers are exposed enough to solder to them.  You still
need via wires, though, even when connecting to the plane on the same
side, as solder has too high a surface tension to just blob it.

I usually squish a little solder paste into the oversize holes, so the
inner layer has solder and flux before I try to connect to it.

example 4-layer taped-up board:
http://www.delorie.com/electronics/usb-gpio/

On 7 Jun 2011, at 14:02, Chris Kleeschulte wrote:

> Question to the group:
> 
> Is it feasible to use 2 one sided .032 boards and glue them together? Or
> even created some sort of 4 sided PCB using glued .032 boards? For the
> 4-sided boards the vias would need to be plated, but had anyone attempted
> this?
> 
> This would double the amount of holes you would need to drill out, but I try
> to stay in the SMD world nowadays.
> 
> 
> The challenge, it seems to me, would be the alignment of the via and part
> holes.

I was thinking of having a go at this. Assuming I could do both boards (for double sided) with the same accuracy, I intended to etch both then drill one. The second layer could have two or three holes carefully drilled and widely spaced. Then I would pin the two boards together through the matching holes in both. After that it should just be a case of drilling again through the existing holes in the first board. 

If the dimensions are god and the alignment holes really are, all the others should be perfectly lined up.

To glue them together, I figured contact adhesive would do. Epoxy would squeeze up through the holes meaning they would need re-drilling again.

I did this once to make a double sided board. I etched both sides on
separate thin board (but I'm not exactly sure of the board thickness), then
glued the 2 boards together copper out on both sides with epoxy. I aligned
the 2 boards together just using a light, and let the epoxy cure a bit
before I actually stuck them together so it wasn't as gooey. It worked out
well, considering the design I was making was a commercial design meant to
be sent off to a boardhouse, but I figured I'd give it a go myself. The via
holes were extremely small, I used the finest drill I had (surplus carbide
pcb drills), and 30 gauge wire wrap wire just barely fit into those holes.
The alignment was almost perfect on the via holes, which was surprising as I
couldn't see the other traces that well through the board. I didn't drill
any alignment holes first, and just drilled everything once the epoxy cured.

For this project anyways, which was a fairly small board (maybe 1.5"
square), the resulting board was very stiff!

Andrew

On Tue, Jun 7, 2011 at 9:31 AM, Peter Harrison
<peter.harrison@...>wrote:

>
>
>
> On 7 Jun 2011, at 14:02, Chris Kleeschulte wrote:
>
> > Question to the group:
> >
> > Is it feasible to use 2 one sided .032 boards and glue them together? Or
> > even created some sort of 4 sided PCB using glued .032 boards? For the
> > 4-sided boards the vias would need to be plated, but had anyone attempted
> > this?
> >
> > This would double the amount of holes you would need to drill out, but I
> try
> > to stay in the SMD world nowadays.
> >
> >
> > The challenge, it seems to me, would be the alignment of the via and part
> > holes.
>
> I was thinking of having a go at this. Assuming I could do both boards (for
> double sided) with the same accuracy, I intended to etch both then drill
> one. The second layer could have two or three holes carefully drilled and
> widely spaced. Then I would pin the two boards together through the matching
> holes in both. After that it should just be a case of drilling again through
> the existing holes in the first board.
>
> If the dimensions are god and the alignment holes really are, all the
> others should be perfectly lined up.
>
> To glue them together, I figured contact adhesive would do. Epoxy would
> squeeze up through the holes meaning they would need re-drilling again.
>
>  
>


[Non-text portions of this message have been removed]