Glueing PCB's Together

[Robert Latest]

I have about 12sq ft of single clad PCB in my junk storage.

With photo resist, or do you use the spray type for that? Never worked for
me ... back in the days.

robert

 

[krw]

I'm thinking of glueing single sided PCB's together 2"x4" to make a
double sided board.

I have:
2 part epoxy
polyester resin + hardener
anaerobic adhesive (threadlocker)
2 part Methacylate adhesive
Automotive gasket sealer

Which is best?
Should I order some special glue instead?
If needed I can cure it in the kitchen oven..

My lesser choices were:
Superglue
Contact cement
RTV Silicone
urethane

I did a LOT of this when I was in college. We had a lathe that
turned out single-sided boards from copper-clad. We used white RTV
to glue them together. There was too much movement for a harder
adhesive, like Epoxy.

 

[JeffM]

I did a LOT of this when I was in college.
We had a lathe that turned out single-sided boards from copper-clad.
Keith

I'm trying to imagine how that worked.
I'm thinking you meant *mill*.

 

[D from BC]

I'm trying to imagine how that worked.
I'm thinking you meant *mill*.

It's gotta be mill..
But maybe a PCB could be mounted on a big spinning disk and lathed.

D from BC

 

[D from BC]

With photo resist, or do you use the spray type for that? Never worked for
me ... back in the days.

robert

My leftover pcb material has no photoresist..
I use presensitized PCB material for my 1206 level SMD work.
D from BC

 

[Rich Grise]

0.032" total thickness...floppy stuff I have about 12sq ft of single
clad PCB in my junk storage. But my projects are often 2 clad..
Hence..the glue idea..

Then just do it - the total would be .064" (or maybe .065, depending on
the epoxy), which isn't that far from "normal".

In fact, you should probably cut the thing in half and glue it all at
once, then cut of what you need when you need it.

But be sure and distribute the epoxy evenly and roll it out well to
make sure you get a good bond all over.

Good Luck!
Rich

 

[ehsjr]

First of all, I think pop-rivets get undeserved bad press!

Maybe if they called 'em "Miracle Rivets" or "Oxy-Rivets?"
(Nevermind, that's a Billy Mayes TV flashback - That guy would sell
his mother!!.)

I think pop-rivets are God's gift to engineers. (You can quote me on
that!)
Of course, it could also explain why they won't let me back in the
Shop anymore...

...unless the polyurethane foam packager gets clogged or goes off
line, and then all of the sudden I'm McGuyver or something.

I don't think you can be McGuyver, unless you use
duct tape.

I've made a "PC board" using contact cement, wooden
board, and copper (roof) flashing. The "traces" were
strips of the flashing, individually glued on. Never
tried making a double sided board by gluing two single
sided boards together, but I'll bet contact cement
would work great.

Ed

 

[D from BC]

I don't think you can be McGuyver, unless you use
duct tape.

I've made a "PC board" using contact cement, wooden
board, and copper (roof) flashing. The "traces" were
strips of the flashing, individually glued on. Never
tried making a double sided board by gluing two single
sided boards together, but I'll bet contact cement
would work great.

Ed

I have spray on contact cement...
I think I have 3M Spray 90 around here somewhere..
I also have contact cement in a can. Water and solvent base.

The Spray 90 probably won't allow me to position, won't squeeze out
and there will be trapped air. Bad...

The liquid contact cement is better but I'm afraid there might be
insufficient initial tack to allow full cure which might take a long
time. If ever..
But as suggested..I could "pin" the PCB's together by soldering
jumpers between boards. This would allow any slow curing adhesive.

However...I do plan on using 2 part epoxy.

The worst adhesive I can think of for this app is Elmers White glue or
glue stick glue...

I also thought of using double sided carpet tape or glue gun glue.


D from BC

 

[mpm]

....and if you add in some fake vias, you might even let in enough
sunlight for some of those UV-cure adhesives. Ha!!

Also, I was desperately trying to figure out how to include the word
"Mucilaginous" in this reply, but just couldn't quite get there.

And FYI - We were all out of Duct Tape, so I ended up fixing that Ford
pickup with a crusty slice of old garlic bread we found under the seat.
(*) That ought to qualify!

(*) That is a true story, though I often embellish it to apply to any
project for which one doesn't have all the proper tools and
equipment. ..which lately seems to be most of them! -mpm
..

 

[Michael A. Terrell]

I don't think you can be McGuyver, unless you use
duct tape.

I've made a "PC board" using contact cement, wooden
board, and copper (roof) flashing. The "traces" were
strips of the flashing, individually glued on. Never
tried making a double sided board by gluing two single
sided boards together, but I'll bet contact cement
would work great.

I had a PC board with a hole about the size of a quarter burnt away.
I used some scrap aluminum to cover the hole, and Bondo to fill the
hole. After it cured I straightened out the copper foils and glued them
to the Bondo. I drilled new holes, and replaced the bad parts. The
board was still in almost daily use several years later.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[mpm]

I had a PC board with a hole about the size of a quarter burnt away.
I used some scrap aluminum to cover the hole, and Bondo to fill the
hole.

Next thing you know, they'll be publishing the dielectric properties
of Bondo!


?

 

[krw]

I'm trying to imagine how that worked.
I'm thinking you meant *mill*.

No, I mean a lathe. Think about bending the copper-clad into a
cylinder and turning it. ;-)

The copper-clad was mounted to one cylinder, the tape-up to the
second. The two cylinders are turned together. When white is
detected on the drawing a knife is driven into the copper-clad. The
sensor and knife mechanisms are mounted to the lathe's screw so the
artwork is 2D scanned.

Did some neat artwork with brass sheets and high contrast photos too.

 

[Robert Latest]

My leftover pcb material has no photoresist..
I use presensitized PCB material for my 1206 level SMD work.

And why don't you just buy dual-layer photosensitized material? Mind you,
I'm sure you have a good reason for wanting to paste together two
single-layer boards (seeing how obvious the dual-layer solution is); I'm
just curious why you want to take that route.

Personally I'm happy to have chucked all that yucky home-etching stuff out
of my basement. But of course twenty years ago I couldn't have afforded
professionally-made prototypes, especially since my layouts were hand-drawn
in black ink on vellum. Occasionally double-sided, too.

robert

 

[D from BC]

And why don't you just buy dual-layer photosensitized material? Mind you,
I'm sure you have a good reason for wanting to paste together two
single-layer boards (seeing how obvious the dual-layer solution is); I'm
just curious why you want to take that route.

Personally I'm happy to have chucked all that yucky home-etching stuff out
of my basement. But of course twenty years ago I couldn't have afforded
professionally-made prototypes, especially since my layouts were hand-drawn
in black ink on vellum. Occasionally double-sided, too.

robert

I have about $100.00 in useless leftover single clad.

In my app, the bottom layer is mostly ground plane. I might not even
have a pattern on that layer..just holes.
Thermal reliefs might be nice but I can brute force solder..
I might not need photoresist or etching for the bottom PCB..

Also..the material I have is too floppy @0.032 for my app...Doubling
it will make it just right.
D from BC

 

[Jim Yanik]

I had a PC board with a hole about the size of a quarter burnt away.
I used some scrap aluminum to cover the hole, and Bondo to fill the
hole. After it cured I straightened out the copper foils and glued them
to the Bondo. I drilled new holes, and replaced the bad parts. The
board was still in almost daily use several years later.

At TEK,I used to Dremel out the burned area of PCBs,place cellophane tape
over the hole,fill with epoxy,and put it in the drying oven to
quicken the cure.Then I would use a grinding burr in the Dremel to level
out the top side,and drill for eyelets,repairing the tracks with salvaged
copper traces and pads or from a PCB repair kit. I never did one as big as
a quarter,though.Maybe 1/2 inch tops.


I used a Hysol optical clear epoxy,608,IIRC.(TEK stocked that epoxy.)

Now I keep a RAKA boat-building epoxy kit handy,plus fumed silica filler to
thicken it. you can get glass fiber fillers too.

 

[Jim Yanik]

Next thing you know, they'll be publishing the dielectric properties
of Bondo!


?

System Three has a nice inexpensive epoxy sample kit complete with an
assortment of fillers like fumed silica,plastic microballoons,wood
flour,chopped plastic fibers;the last time I checked,the cost of the kit
was $10 US PPD.
There's more than enough to do several PCBs.
Plus you get the Epoxy Book,a very useful source of info on epoxies.(it's
also downloadable)

Get some 1 oz.graduated cups from the drugstore or WalMart to mix up small
amounts. They are very handy. Oral syringes are useful for small batches.

 

[John Popelish]

I have about $100.00 in useless leftover single clad.

In my app, the bottom layer is mostly ground plane. I might not even
have a pattern on that layer..just holes.
Thermal reliefs might be nice but I can brute force solder..
I might not need photoresist or etching for the bottom PCB..

Also..the material I have is too floppy @0.032 for my app...Doubling
it will make it just right.

If I were doing this, I would tape plastic sheeting to both
copper surfaces, to prevent getting any epoxy fingerprints
on them, and then paint both with epoxy, stack, weight over
disposable surface like newsprint, and let cure. Epoxy
oozing out all around would be good, just an indication that
no voids were left between the boards. Removing the taped
cover would also remove any extra epoxy.

 

[Michael A. Terrell]

At TEK,I used to Dremel out the burned area of PCBs,place cellophane tape
over the hole,fill with epoxy,and put it in the drying oven to
quicken the cure.Then I would use a grinding burr in the Dremel to level
out the top side,and drill for eyelets,repairing the tracks with salvaged
copper traces and pads or from a PCB repair kit. I never did one as big as
a quarter,though.Maybe 1/2 inch tops.

I used a Hysol optical clear epoxy,608,IIRC.(TEK stocked that epoxy.)

Now I keep a RAKA boat-building epoxy kit handy,plus fumed silica filler to
thicken it. you can get glass fiber fillers too.

Sounds good, but Bondo was all I could find in 1970. Epoxy wasn't
easy find, back then.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[D from BC]

If I were doing this, I would tape plastic sheeting to both
copper surfaces, to prevent getting any epoxy fingerprints
on them, and then paint both with epoxy, stack, weight over
disposable surface like newsprint, and let cure. Epoxy
oozing out all around would be good, just an indication that
no voids were left between the boards. Removing the taped
cover would also remove any extra epoxy.

Good idea..
I have lots of adhesive vinyl graphics material here that I can put on
the copper to keep the epoxy spill over away..
D from BC

 

[D from BC]

System Three has a nice inexpensive epoxy sample kit complete with an
assortment of fillers like fumed silica,plastic microballoons,wood
flour,chopped plastic fibers;the last time I checked,the cost of the kit
was $10 US PPD.
There's more than enough to do several PCBs.
Plus you get the Epoxy Book,a very useful source of info on epoxies.(it's
also downloadable)

Get some 1 oz.graduated cups from the drugstore or WalMart to mix up small
amounts. They are very handy. Oral syringes are useful for small batches.

Which reminds me...
I put my heat sink grease, rosin and silicone in medical syringes.
D from BC