Homebrew PCBs

Hi all,

I have been making some PCBs of late (just getting rolling with some 
projects as I learn about electronics).  The first few boards I 
etched were on the brown fiberglass type material - worked good but 
can dull a band saw blade in a heart beat.

I purchased some large boards from Kelvin and have been etching / 
drilling these for my most recent series of boards.  This material 
is whitish in color, crumbles when you try to cut it with a sheet 
metal shear (hand snips), however, cuts great on the band saw and 
doesn't seem to dull the blade.  

Having made a slight error on a couple of them, I needed to trim 
down the edge. As this wasn't discovered until the components were 
on, I couldn't just run it through the table saw again.  So I trried 
the snips - didn't work.  Ready to give up, I thought I would run it 
against my belt sander and bingo - this stuff sands just wonderful!  
Much easier to sand than the fiberglass products and stinks much 
less too.

Stefan has told me all about the various materials used for PCBs, 
and now I am wondering why there are so many different materials and 
what the advantages / diss-advantages are of them. 

In my very limitted experiences, I am really liking this white 
material but I suspect it is not the best material to use.

So, if you all don't mind, can we discuss the merits of the various 
materials?

Chris

In a message dated 10/16/2005 5:41:58 P.M. Central Daylight Time,  
lcdpublishing@... writes:

So, if  you all don't mind, can we discuss the merits of the various  
materials?<<



Chris:  
 
I use ONLY FR-4 (green fiber-glass epoxy impregnated).   Reason: It is THROWN 
away by the local PCB house when 4" or less (usually 4.5"  or less!).  A 
stack of 2" of that waste will last me years!  It WILL  nupper a bandsaw blade 
rapidly, but if you have to cut more than one or two, it  is worth the sacrifice. 
 Then I always disk-sand the edges before  attempting to etc.  Carbide 
router-bits for odd shapes or "square holes",  etc.  I can't even FIND phenolic 
("Bakelite") copper-clad!  I use ONLY  "PCB drill-bits" which are solid-carbide 
with 1/8" dia. shank, regardless of  drill-size.  These are available in various 
commonly-used diameters from  the usual mail-order vendors in standard boxes 
of 50 for about half or less the  usual "new price" of about $2.00 per bit.  I 
have a little home-brew CNC  X-Y drill (resting, now, until I can get a "PC" 
connected to it, as its  "master", a 1978 "PET" died a year back, and, well . 
. .).  
 
ONE caveat:  The "professional" stuff is usually only 1/2  oz. copper, as it 
is ALWAYS used for plated-through hole work, and that  increases the copper to 
1 oz. or more.  But if you work carefully, you can  "live with it" for the 
PRICE of the stuff!  
 
I just wish it were EASY to plate-through!  I'd MUCH  rather be able to do 
that than to use "jumpers" and "soldered-in vias"  etc.  BOO  HOO ! ! !
 
ONE thing about FR-4:  It is THE industry-standard, and  GOOD stuff!
 
Jan Rowland


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

----- Original Message ----- 

From: "lcdpublishing" <lcdpublishing@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, October 16, 2005 11:41 PM
Subject: [Homebrew_PCBs] Different PCB materials - open for discussion...


> Hi all,
>
> I have been making some PCBs of late (just getting rolling with some
> projects as I learn about electronics).  The first few boards I
> etched were on the brown fiberglass type material - worked good but
> can dull a band saw blade in a heart beat.
>
> I purchased some large boards from Kelvin and have been etching /
> drilling these for my most recent series of boards.  This material
> is whitish in color, crumbles when you try to cut it with a sheet
> metal shear (hand snips), however, cuts great on the band saw and
> doesn't seem to dull the blade.
>
> Having made a slight error on a couple of them, I needed to trim
> down the edge. As this wasn't discovered until the components were
> on, I couldn't just run it through the table saw again.  So I trried
> the snips - didn't work.  Ready to give up, I thought I would run it
> against my belt sander and bingo - this stuff sands just wonderful!
> Much easier to sand than the fiberglass products and stinks much
> less too.

That sounds like FCB 16:

"A fibre glass and paper composite laminate manufactured to the same high 
quality standards as Fotoboard but giving certain price and weight 
advantages. FPC-16 consists of two fibre glass outer layers with a paper 
composite in between. The 1 oz copper thickness and high quality Photoresist 
are the same as Fotoboard. The construction of FPC-16 makes it light, easy 
to cut and drill. It also costs less to manufacture making it cheaper than 
Fotoboard. Various single and double sided options are available all 
supplied as single sheets."

I prefer it to FR4 as it is much easier to cut and drill. It's also cheaper. 
A disadvantage is that one can't see through it like FR4.

Leon
 

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In a message dated 10/16/2005 9:19:07 P.M. Central Daylight Time,  
JanRwl@... writes:

. . .  attempting to etc.  Carbide 


Apparently my Spell Checker thinks "etch" is  "etc."


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

On Mon, 17 Oct 2005 00:41:30 +0200, lcdpublishing  
<lcdpublishing@...> wrote:

>
> In my very limitted experiences, I am really liking this white
> material but I suspect it is not the best material to use.
> So, if you all don't mind, can we discuss the merits of the various
> materials?
> Chris


It is a cheaper material, yes, but it is not going to give you any trouble.

FR4 is more mechanically stable and probably has better electrical  
characteristics as well, which you don't need to mind.
Also, you can only plate through holes on FR4, the paper does not produce  
acceptable holewalls. Not an issue for us.

FR1 and even phenolic boards are still widely used in industry, for  
"cheap" jobs like TV sets and other low-density stuff like that. Those are  
often done single-sided so the paper is no problem.


As others said, FR4 can often be bought very cheap as cutoffs, so it is  
for me cheaper than FR1. Because of that i use the FR1 i have only for  
prototypes, which will not see permament service, not because it is  
inferior but becasue i have to use FR4 for most stuff anyway so better use  
it where the harder work has some lasting effect.

ST

Cool, then I will continue to work with it and save my band saw 
blades for cutting wood!

Chris



--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
>
> On Mon, 17 Oct 2005 00:41:30 +0200, lcdpublishing  
> <lcdpublishing@y...> wrote:
> 
> >
> > In my very limitted experiences, I am really liking this white
> > material but I suspect it is not the best material to use.
> > So, if you all don't mind, can we discuss the merits of the 
various
> > materials?
> > Chris
> 
> 
> It is a cheaper material, yes, but it is not going to give you any 
trouble.
> 
> FR4 is more mechanically stable and probably has better 
electrical  
> characteristics as well, which you don't need to mind.
> Also, you can only plate through holes on FR4, the paper does not 
produce  
> acceptable holewalls. Not an issue for us.
> 
> FR1 and even phenolic boards are still widely used in industry, 
for  
> "cheap" jobs like TV sets and other low-density stuff like that. 
Those are  
> often done single-sided so the paper is no problem.
> 
> 
> As others said, FR4 can often be bought very cheap as cutoffs, so 
it is  
> for me cheaper than FR1. Because of that i use the FR1 i have only 
for  
> prototypes, which will not see permament service, not because it 
is  
> inferior but becasue i have to use FR4 for most stuff anyway so 
better use  

> it where the harder work has some lasting effect.
> 
> ST
>

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
...
> FR1 and even phenolic boards are still widely used in industry, for  
> "cheap" jobs like TV sets and other low-density stuff like that.
Those are  
> often done single-sided so the paper is no problem.

I wish that were true of all TVs! Some brands have double sided with
traces following tortuous paths across many plated-through holes and
SMT jumpers.

Steve Greenfield

On Thu, 20 Oct 2005 18:45:21 +0200, Steve <alienrelics@...> wrote:

> I wish that were true of all TVs! Some brands have double sided with
> traces following tortuous paths across many plated-through holes and
> SMT jumpers.
> Steve Greenfield


You mean the more expensive sets, that would be worth repairing ;-)

I only buy the cheapest ones, and all 4 i have here now, of different  
brands and screen sizes, have the same board ;-)
One of them is faulty / no repair already so i have parts....


The more expensive TVs tend to have modules and smd / doublesided boards.  
I have found they are no more reliable than the cheap sets and i really  
don't need any of the fancy features they might offer (which i never know  
about anyway).


ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
>
> On Thu, 20 Oct 2005 18:45:21 +0200, Steve <alienrelics@y...> wrote:
> 
> > I wish that were true of all TVs! Some brands have double sided with
> > traces following tortuous paths across many plated-through holes and
> > SMT jumpers.
> > Steve Greenfield
> 
> 
> You mean the more expensive sets, that would be worth repairing ;-)

RCA... shudder.

> The more expensive TVs tend to have modules and smd / doublesided
boards.  
> I have found they are no more reliable than the cheap sets and i
really  
> don't need any of the fancy features they might offer (which i never
know  
> about anyway).

I worked at a shop that had the RCA warranty contract for the local TV
stores. It was not uncommon to see a TV come in 3 times for repair
-before- it got sold, at which point RCA junked the set. 99% of the
time: bad solder joints.

You might find one connection that on the schematic is just a wire
from one IC to another, on the board may cross from one side of the
board to another several times, passing through several SMT jumpers
(ie, "zero ohm resistors"). A nightmare to find a bad solder joint.

The owner of the shop made sure to find the one single joint he could
resolder to get the TV working again. His warranty reports would say
things like "soldered forward joint of J312".

Mine didn't come back. But my warranty reports said things like
"resoldered ~150 solder joints on SMT resistors and jumpers".

Steve Greenfield

On Sun, 23 Oct 2005 21:53:01 +0200, Steve <alienrelics@...> wrote:

> The owner of the shop made sure to find the one single joint he could
> resolder to get the TV working again. His warranty reports would say
> things like "soldered forward joint of J312".
> Mine didn't come back. But my warranty reports said things like
> "resoldered ~150 solder joints on SMT resistors and jumpers".
> Steve Greenfield


hehe, didn't yours come back because they were fixed or because the owner  
didn't want to risk a outrageous repair bill again ;-) ?

Those cheapo sets are so economized, there's just no money for stuff like  
zero-ohms. There are wire bridges however. There isn't much in there to go  
wrong.

The bloddy B on my keyboard is acting up today, requiring quite insane  
pressure to function. As if i wouldn't have enough work already that needs  
fixing too.....


ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
>
> On Sun, 23 Oct 2005 21:53:01 +0200, Steve <alienrelics@y...> wrote:
> 
> > The owner of the shop made sure to find the one single joint he could
> > resolder to get the TV working again. His warranty reports would say
> > things like "soldered forward joint of J312".
> > Mine didn't come back. But my warranty reports said things like
> > "resoldered ~150 solder joints on SMT resistors and jumpers".
> > Steve Greenfield
> 
> 
> hehe, didn't yours come back because they were fixed or because the
owner  
> didn't want to risk a outrageous repair bill again ;-) ?

I take it you haven't done warranty work. The shop gets paid a flat rate.

Mine didn't come back because I fixed them. The owner's came back
because he intentionally fixed them just enough to work. Yes, he said
this to me, that I was costing the shop money because mine didn't come
back.

> Those cheapo sets are so economized, there's just no money for stuff
like  
> zero-ohms. There are wire bridges however. There isn't much in there
to go  
> wrong.

Heh.... yep, more features means more things to go wrong.

Steve Greenfield