Homebrew PCBs

Sorry to spit out this "message flood", but I'm having more questions 
than answers lately. :(

I tried my first PCB labeling the other night with my usual toner 
transfer method and it didn't go very well. I couldn't help but notice 
how the "raised" copper areas of a double-sided board prevent the 
paper from laying flat on the board and screw up the transfer in the 
low areas.

Is the toner/iron process a lost cause under those circumstances, or 
does anyone know of a workaround? FWIW, I use my previous brand of 
JetPrint photo paper for non-trace jobs, where I need a clean black 
transfer with no left over paper. This is the type where the paper 
sort of slides off after soaking, leaving a light "goo" on the surface 
which comes off easily with soap. I found a method of getting much 
more consistent transfers onto metal, by spraying a light mist of 
Krylon clear acrylic on the substrate beforehand. Unfortunately, this 
didn't seem to help on the PCB labels.

                              -Thanks Again!
George

It helps to have a elastic material pressing the paper into the valleys  
between traces.
I run it transfer side down through the fuser so the silicone rubber  
roller presses it in.
Still i can't get a continuous line, but it's only a tiny break where  
copper and blank board meets. I try to keep text to one surface, but  
outlines are OK.

ST

On Wed, 07 Dec 2005 01:31:46 +0100, soffee83 <soffee83@...> wrote:

> Sorry to spit out this "message flood", but I'm having more questions
> than answers lately. :(
>
> I tried my first PCB labeling the other night with my usual toner
> transfer method and it didn't go very well. I couldn't help but notice
> how the "raised" copper areas of a double-sided board prevent the
> paper from laying flat on the board and screw up the transfer in the
> low areas.
>
> Is the toner/iron process a lost cause under those circumstances, or
> does anyone know of a workaround? FWIW, I use my previous brand of
> JetPrint photo paper for non-trace jobs, where I need a clean black
> transfer with no left over paper. This is the type where the paper
> sort of slides off after soaking, leaving a light "goo" on the surface
> which comes off easily with soap. I found a method of getting much
> more consistent transfers onto metal, by spraying a light mist of
> Krylon clear acrylic on the substrate beforehand. Unfortunately, this
> didn't seem to help on the PCB labels.
>
>                               -Thanks Again!
> George
>

Stefan,

Thanks! That's sort of what I figured when I tried it, but I use the 
iron here, so I'm not sure I could do the exact same thing. I thought 
that maybe a folded-over wet paper towel would give it some "squish" 
for the last couple ironings, but it didn't help much. This thing I 
was doing is sort of a weird one anyway. It's a proto-circuit for 
testing a PIC based hardware controller, so it's actually going to 
stay in "PCB form" maybe on a plywood panel, with no chassis, but I'll 
be using it a lot. Normally, the top labels aren't as important to me. 
I can usually just refer to a paper copy of my component layout while 
I populate. 

I figured that the graphics which actually crossed copper wouldn't 
make a clean transition like you said. If I have to do something like 
that again, I'll probably try to get as much text as I can into the 
initial etched copper transfer and not fight with the subsequent toner 
labeling.

                              -Take Care
George

PS- I did want to try a laminator just for the heck of it, but that 
Staples after Thanksgiving deal fell through. I think I might mail 
them about that suspected "bait & switch" offer.

It is a bit of an issue, but it does work with elastic pressure.
Here you see one of the first boards i made with legend on copper, i  
believe the first or second ever:
<http://trethan.at.tf/pub/comp_bot.jpg>
It is on 18u copper, which makes for smaller steps and no break, sometimes.
I haven't really worked on it much, since i avoid having important  
information in the gaps, i put the text on copper and use a ground  
plane/copper pour usually. You can't read so well across the contrasting  
surfaces anyway.

I dunno how it can be done with an iron, i think with something like a  
silicone baking sheet you mightn't get enough pressure per area. But Steve  
said there are such sheets for use in t-shirt presses, i think...

About the laminator, the deal seemes to have been pretty lame from the  
reports here. I'm not sure anyway if those laminators have a rubber roller  
or two metal ones.

ST

On Wed, 07 Dec 2005 22:12:19 +0100, soffee83 <soffee83@...> wrote:

> Stefan,
>
>
> Thanks! That's sort of what I figured when I tried it, but I use the
>
> iron here, so I'm not sure I could do the exact same thing. I thought
>
> that maybe a folded-over wet paper towel would give it some "squish"
>
> for the last couple ironings, but it didn't help much. This thing I
>
> was doing is sort of a weird one anyway. It's a proto-circuit for
>
> testing a PIC based hardware controller, so it' ..

Stefan,

Thanks again. Man, you take a damn good picture! That transfer looks 
about a hundred times better than mine did too. On my double-sided 
boards, I'm supposedly dealing with 1oz of copper per side. The 
transitions look more troublesome than yours. The material is the less 
translucent greenish-brown colored stuff too, if that had any affect.

The Staples unit was supposed to have been the same one Pulsar bundles 
for PCB transfers (you probably already knew). I don't know if it has 
any rubber in it either. I've got a couple long rubber rollers here, 
one of which I've mounted by it's axles to a square aluminum bar via 
standoffs. That one was from a big Xerox machine. I use it with a drum 
finishing thing I made (manual feed between two sets of rollers). I 
know nothing about printer/laminator guts, but depending on where and 
how the heat source factors into that, I wonder if that idea would be 
half as functional as it is fun to think about.

I also wonder if the "wipe the back of the paper down with acetone-
soaked cotton balls" method would work for that. I've always imagined 
that process blurring the prints, but it would have the same "squish" 
you describe with the rubber.

                            -George

On Thu, 08 Dec 2005 00:54:43 +0100, soffee83 <soffee83@...> wrote:

> Stefan,
>
>
> Thanks again. Man, you take a damn good picture!

I reckon it is actually a scan. I did it ages ago and i don't remember.

> That transfer looks
>
> about a hundred times better than mine did too. On my double-sided
>
> boards, I'm supposedly dealing with 1oz of copper per side. The
>
> transitions look more troublesome than yours. The material is the less
>
> translucent greenish-brown colored stuff too, if that had any affect.

Usually the freshly etched epoxy takes toner very well, if it reaches it.  
So the material shouldn't matter.
I dunno why my boards are such strange material, i'm not sure if it is  
FR4, it sure has all the required glass but the resin might be something  
else.


>
> The Staples unit was supposed to have been the same one Pulsar bundles
>
> for PCB transfers (you probably already knew). I don't know if it has
>
> any rubber in it either. I've got a couple long rubber rollers here,
>
> one of which I've mounted by it's axles to a square aluminum bar via
>
> standoffs. That one was from a big Xerox machine. I use it with a drum
>
> finishing thing I made (manual feed between two sets of rollers). I
>
> know nothing about printer/laminator guts, but depending on where and
>
> how the heat source factors into that, I wonder if that idea would be
>
> half as functional as it is fun to think about.

If you put your board transfer up on a iron, and the "roll" a heat-proof  
rubber roller over the top of it it might just work.
Allow a bit higher temp and some time to heat through the PCB, maybe a  
second iron on top that is removed just before rolling.

I reckon a paper that releases without soak makes things easier here  
(althought the picture was made with normal inkjet i'm sure).


> I also wonder if the "wipe the back of the paper down with acetone-
>
> soaked cotton balls" method would work for that. I've always imagined
>
> that process blurring the prints, but it would have the same "squish"
>
> you describe with the rubber.
>
>
>                             -George

Well, that sure couldn't be done on a hot board as the acetone would cool  
it or instantly evaporate. I really don't think it would do much.
I have never heard of that method, what's it do?

But a dry balled-up towel or rag might be useable to squish the paper down  
on the upside-down iron.

ST

Hey again Stefan and all,

I think I do have that same color and type of board as you in some 
single sided stuff I was using. I've got some cheap single sided now 
that's more weird looking, but seems to do quite well. It's a 
totally opaque light beige, sort of a flesh tone, with a fairly tight 
weave of whatever's in it.

I'm not sure if I'd try that iron rolling. I'd be afraid of trying to 
get enough heat up through the board bottom to melt what was on the 
paper a few layers away. I saw the acetone thing mentioned a few 
times, but it could have been all for "toner to metal" transfers. I 
also remember one thread with someone who couldn't get any acceptable 
results from it and decided it was "toner dependant".

     -George (who still hasn't gotten his no-stick Reynolds wrap)

Here's some snipped info from a forum I frequent--

Align the paper on the metal sheet, design side down, and secure the 
edges with tape. Make sure the paper is flat against the metal.
Now the nasty part: Transfering the design from the paper to the 
metal. This is done by releasing the fused toner on the paper with 
Acetone. <-some acetone warnings snipped-> Completely wet the paper 
with acetone (the paper will turn translucent.) by rubbing it with a 
saturated cotton ball. Apply good pressure, this will help the 
transfer process. Wait a few minutes, remove the tape and carefully 
peel back the paper. Most of the design should now stick to the metal 
surface. Handle it with care because it will smudge off if you aren't 
careful. The design lasts long enough for me to pierce (drill) and saw 
(or punch) out the bits I don't want.  If you do accidentally wipe off 
the design, just clean the metal with a cotton ball and some acetone 
(did I mention the gloves and the ventilation?) wipe it dry and try 
again. It's quick, cheap, works pretty well and there's no annoying 
paper and glue gumming up the drill bits.

PS- I just noticed that I don't see any mention of our usual slick 
paper or anything in that acetone post. I guess it's just regular 
paper. If I can dig up any better info, I'll let you know.

-George

On Thu, 08 Dec 2005 12:53:29 +0100, soffee83 <soffee83@...> wrote:

> Hey again Stefan and all,
>
>
> I think I do have that same color and type of board as you in some
>
> single sided stuff I was using. I've got some cheap single sided now
>
> that's more weird looking, but seems to do quite well. It's a
>
> totally opaque light beige, sort of a flesh tone, with a fairly tight
>
> weave of whatever's in it.
>
>
> I'm not sure if I'd try that iron rolling. I'd be afraid of trying to
>
> get enough heat up through the board bottom to melt what was on the
>
> paper a few layers away. I saw the acetone thing mentioned a few
>
> times, but it could have been all for "toner to metal" transfers. I
>
> also remember one thread with someone who couldn't get any acceptable
>
> results from it and decided it was "toner dependant".
>
>
>      -George (who still hasn't gotten his no-stick Reynolds wrap)


The really whitish board stuff is probably FR1, with only one layer of  
glass and phenolic paper in between. I've got some of this too.

I think our "not so transparent" but full glass material is G10 or XPC.  
Both have the usual 8 layers glass, XPC uses phenolic resin and G10 uses  
epoxy, but not the same as FR4. I don't think it matters much for homebrew  
projects, as i usually don't design for my boards to catch fire anyway ;-)

It should be possible to identify this via the logo in the middle layer,  
but i have not had any luck with that yet since it is red, which means  
FR4, but isn't FR4 at all....

Anyway, what i have found is that the real FR4 i have seems to take the  
toner badly, especially if you use single-sided stock and try to transfer  
on the smooth side.

ST

Stefan,

I believe that horribly stuff I have been having all the trouble with 
is FR4 material - this is the new stuff I got that wouldn't accept the 
toner transfer until I did the pre-etch.  However, I was also doing 
toner transfer of legends on the bare expoxy side too and it wouldn't 
take either until I sanded it with 600 grit paper and then polished it 
with 0000 steel wool.  After that, the toner stuck pretty good to the 
epoxy.  This was done using a magazine page and an iron.

Chris



> Anyway, what i have found is that the real FR4 i have seems to take 
the  
> toner badly, especially if you use single-sided stock and try to 
transfer  

> on the smooth side.
> 
> ST
>

On Thu, 08 Dec 2005 13:54:27 +0100, lcdpublishing  
<lcdpublishing@...> wrote:

> Stefan,
>
>
> I believe that horribly stuff I have been having all the trouble with
>
> is FR4 material - this is the new stuff I got that wouldn't accept the
>
> toner transfer until I did the pre-etch.  However, I was also doing
>
> toner transfer of legends on the bare expoxy side too and it wouldn't
>
> take either until I sanded it with 600 grit paper and then polished it
>
> with 0000 steel wool.  After that, the toner stuck pretty good to the
>
> epoxy.  This was done using a magazine page and an iron.
>
>
> Chris


I tried sanding it, but it still would not adhere as well as on the other  
material.

ST

I just looked up my email here. The solid beige stuff I bought is 
supposedly CEM1 @.047. The double-sided I was just trying to print on 
is the FR4 and it's .093 (yikes!). Either one seems rigid enough for 
what I'm doing though and everything will likely be supported on 
standoffs or something, especially stuff with controls.

I don't believe either of these has taken toner well, but I can 
probably find a working combo for printing the tops of the flatter 
single-sided etches. I'm looking at a CAT5 tester on that beige stuff 
I built here, which I printed a bunch of junk on and everything stuck 
but one letter. However, that was with Staples paper, so it has that 
nasty gray film on it. I coated it with a spray to darken it some, but 
it's still gray. Wetting that residue makes it a bit better looking, 
but then it dries out. I wonder if there's a paint, etc. that would 
keep it black? Weird thing is, transfers tend to fuse into the PCB 
material unlike the copper, so even the ones that didn't take have a 
leftover ghost if you try to wipe them off.

Sanding or leveling the top with something seems like it may help. A 
lot of mine has that "cloth" texture which probably doesn't encourage 
a good transfer. I don't know if sanding would just bring up more 
cloth though.

Anyone struggling with it may try a light spray before the toner goes 
on. Krylon "crystal clear" acrylic made a world of difference on 
aluminum with the JetPrint paper. It may even take less heat and 
heating time, as it sort of fuses into and "grabs" the toner.

To anyone here- 

Other than the obvious strength and copper thickness or quality 
factors, what exactly should be our concerns with the different types 
of PCB substrate? I'm not in danger of excessive heat either, but I 
don't think I would care for any "warping", etc.

                              -George

On Thu, 08 Dec 2005 22:03:42 +0100, soffee83 <soffee83@...> wrote:

> I just looked up my email here. The solid beige stuff I bought is
> supposedly CEM1 @.047. The double-sided I was just trying to print on
> is the FR4 and it's .093 (yikes!). Either one seems rigid enough for
> what I'm doing though and everything will likely be supported on
> standoffs or something, especially stuff with controls.
>
>
> I don't believe either of these has taken toner well, but I can
> probably find a working combo for printing the tops of the flatter
> single-sided etches. I'm looking at a CAT5 tester on that beige stuff
> I built here, which I printed a bunch of junk on and everything stuck
> but one letter. However, that was with Staples paper, so it has that
> nasty gray film on it. I coated it with a spray to darken it some, but
> it's still gray. Wetting that residue makes it a bit better looking,
> but then it dries out. I wonder if there's a paint, etc. that would
> keep it black? Weird thing is, transfers tend to fuse into the PCB
> material unlike the copper, so even the ones that didn't take have a
> leftover ghost if you try to wipe them off.

Ah, glad to hear i'm not seeing ghosts then ;-). It's the same here with  
the fused in toner.
About the white residue, i also thought it would go black with laquer, but  
the damn thing doesn't want to cooperate. You can get it black by  
polishing with abrasive kitchen cleaner or toothpaste and a rag. Nowadays  
i use silicone coated paper for legend to avoid the residue.

> Sanding or leveling the top with something seems like it may help. A
> lot of mine has that "cloth" texture which probably doesn't encourage
> a good transfer. I don't know if sanding would just bring up more
> cloth though.

Probably only on sides where no copper was etched away. The copper leaves  
about the roughest surface you can possibly get (for good adhesion), and  
the toner holds very well if kept oil-free.
The cloth texture doesn't seem to be a problem here, however don't try to  
peel boards apart in the middle and transfer on the _really_ cloth  
textured surfact then ;-)


> Anyone struggling with it may try a light spray before the toner goes
> on. Krylon "crystal clear" acrylic made a world of difference on
> aluminum with the JetPrint paper. It may even take less heat and
> heating time, as it sort of fuses into and "grabs" the toner.

I haven't tried that. It might just allow me to transfer to the blank side  
of FR4, which despite sanding doesn't work great for me.

> To anyone here-
> Other than the obvious strength and copper thickness or quality
> factors, what exactly should be our concerns with the different types
> of PCB substrate? I'm not in danger of excessive heat either, but I
> don't think I would care for any "warping", etc.

Mechanically the full glass materials are much the same strength i think,  
the CEM stuff with paper in between a bit less and real FR4 a tiny bit  
more stiff than the yellowish stuff. The rest is mostly fire retardancy  
and electrical properties that mostly don't matter.

ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
>The rest is mostly fire retardancy and electrical properties that 
>mostly don't matter.

Good to hear for a cheapskate like myself. I bought something like a 
12" square piece a while back locally, and it was like 15 or 18 
dollars. I got a lifetime supply (10pcs) of that beige CEM-1 in 
10"x24" from a guy that sells on eBay for 20 bucks. :)

FWIW- That was Chris from www.pcbmaterialworld.com
           -eBay name was ACGIII

I just looked at some of his completed auctions and he had FR-4 and 
CEM-3 bundles, but the pictures all had the same white edge like my 
CEM-1 (could just have used the same photo). Good guy to deal with 
regardless (I think he's in Illinois).

On the paper residue, it would seem like a mild water-based black 
latex would soak into that stuff and could be overcoated when dry. At 
the very least, I can't see it letting the gray reappear, even if it 
didn't make a really solid coat. It also might be weak enough that you 
could just wipe it on with a wet paper towel and have it mainly take 
to the paper, or you could wipe the black residue from the surrounding 
board afterward (don't know). It sure would be a nice trick, as that 
paper seems to transfer differently than most. Also would be great if 
it would absorb some more interesting colors too!

                              -George

PS- Just got my Reynolds "Release" foil, and was able to merely sit 
here on my a$$ and wait for it. ;) (there was a grocery run happening)