Homebrew PCBs

Using pieces of wire, resistor legs, or header pins for hidden vias
(under surface mount parts; something I need to do often) is not
really workable.  Even for exposed vias, I find the method a pain and
the results ugly.  Is it possible to actually buy real vias and some
cheap tool to insert them?  For me, vias are the main reason on some
boards to not bother DIYing and outsourcing it.

On Thu, 07 Dec 2006 12:10:24 +0100, bobysgotguns <bdt@...> wrote:

> Using pieces of wire, resistor legs, or header pins for hidden vias
> (under surface mount parts; something I need to do often) is not
> really workable.  Even for exposed vias, I find the method a pain and
> the results ugly.  Is it possible to actually buy real vias and some
> cheap tool to insert them?  For me, vias are the main reason on some
> boards to not bother DIYing and outsourcing it.


vias are chemically plated, you can not buy them as components. There are  
a few ways to make fake ones though, none that great IMO.

ST

http://www.bungard.com/seiten/p-favorit.htm

Marcel

Stefan Trethan wrote:

> On Thu, 07 Dec 2006 12:10:24 +0100, bobysgotguns <bdt@...> wrote:
> 
>> Using pieces of wire, resistor legs, or header pins for hidden vias
>> (under surface mount parts; something I need to do often) is not
>> really workable.  Even for exposed vias, I find the method a pain and
>> the results ugly.  Is it possible to actually buy real vias and some
>> cheap tool to insert them?  For me, vias are the main reason on some
>> boards to not bother DIYing and outsourcing it.
> 
> 
> vias are chemically plated, you can not buy them as components. There
> are a few ways to make fake ones though, none that great IMO.
> 
> ST
> 
> 
> Be sure to visit the group home and check for new Links, Files, and
> Photos: http://groups.yahoo.com/group/Homebrew_PCBs
> 
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
> 
> 
>

I'm referring to something like this:
http://www.megauk.com/through_hole_rivets.php
They are simple copper rivets, which can be fitted with a standard punch 
tool -- no need to buy the kit, just the refills.  The problem is, I 
can't find anything like this in North America.  The only similar item I 
  found was far more expensive at $80 per bag of thousand, compare to 15 
pounds (<$30) (and I don't really need bags of thousand for each size...)


Stefan Trethan wrote:

> On Thu, 07 Dec 2006 12:10:24 +0100, bobysgotguns <bdt@...> wrote:
> 
>> Using pieces of wire, resistor legs, or header pins for hidden vias
>> (under surface mount parts; something I need to do often) is not
>> really workable.  Even for exposed vias, I find the method a pain and
>> the results ugly.  Is it possible to actually buy real vias and some
>> cheap tool to insert them?  For me, vias are the main reason on some
>> boards to not bother DIYing and outsourcing it.
> 
> 
> vias are chemically plated, you can not buy them as components. There are  
> a few ways to make fake ones though, none that great IMO.
> 
> ST
> 
> 
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
> 
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
> Yahoo! Groups Links
> 
> 
> 
> 
>

Borislav Trifonov <bdt@...> writes:
> compare to 15 pounds (<$30)

So, what's stopping you from buying the UK$15 refills?  Or call
their USA distributor.

> (and I don't really need bags of thousand for each size...)

For vias at least, you only need one size (holes for pins is a
different story), and 1000 seems reasonable.  I just checked a recent
4.5x3.5" board and it had nearly 300 vias (12 mil) all by itself, plus
168 pin holes, a majority of which were close enough in size (28/35/40
mil) that I could probably get away with one size for all of them.

Hmmm... I wonder if we can use standard copper tubing for this.  The
issues would be (1) getting small enough sizes, and (2) cutting them
without destroying them.

(humor: I googled for "tiny copper" and half the sponsored links were
for a "mini cooper" :)

On Fri, 08 Dec 2006 14:49:53 +0100, DJ Delorie <dj@...> wrote:

>
> For vias at least, you only need one size (holes for pins is a
> different story), and 1000 seems reasonable.  I just checked a recent
> 4.5x3.5" board and it had nearly 300 vias (12 mil) all by itself, plus
> 168 pin holes, a majority of which were close enough in size (28/35/40
> mil) that I could probably get away with one size for all of them.
> Hmmm... I wonder if we can use standard copper tubing for this.  The
> issues would be (1) getting small enough sizes, and (2) cutting them
> without destroying them.
> (humor: I googled for "tiny copper" and half the sponsored links were
> for a "mini cooper" :)


And how much fun would it be to place 300 vias a board, manually? Not to  
speak of the other problems like them being much larger than regular vias  
and they protrude a bit from the board which may be impossible under SMD  
parts. Also, with 300 vias a board you only get 3 boards out of your 1000  
pieces pack, for 15 pounds? I don't think so, you can almost have the  
boards made for that in places.

You can also use ferrules, but the smallest size i could find is still  
rather large. Thin copper tubing is also used for capillary lines  
(thermostats etc.), but you'd need to cut that, and it doesn't have a  
flanged end, and it's probably still large, or too thick walled.
Those eyelets were useful to some extent before SMD, because you could use  
throughhole parts on non-pth boards that could not be soldered top side  
and still have a via there. But now, with the small sizes, there just  
seems little to no point in them.


I'm _very_ cheap, and very much in favor of homebrewing, but the whole  
eyelets thing has always struck me as rather nonsensical from a  
price/reliability/effort/usefulness perspective. If you are going to make  
that sort of compromise, you are much better off putting the extra effort  
into layout to get away with no or very few (solderable) vias. If you  
can't do that, it seems better to have the board made than using any of  
the commercial fake via solutions.

Anyway, just my opinion.

ST

Where did you find the rivets for $80/1000 in North America?  I'm 
paying almost $30/100 at Circuit Technology (circuittechctr.com). John



--- In Homebrew_PCBs@yahoogroups.com, Borislav Trifonov <bdt@...> wrote:
>  The only similar item I 
>   found was far more expensive at $80 per bag of thousand, compare to 
15 
> pounds (<$30) (and I don't really need bags of thousand for each 
size...)

On Fri, 08 Dec 2006 15:48:05 +0100, jpanhalt <janhalt@...> wrote:

> Where did you find the rivets for $80/1000 in North America?  I'm
> paying almost $30/100 at Circuit Technology (circuittechctr.com). John


that's 30c a rivet. what makes you do that?

ST

DJ Delorie wrote:
> Hmmm... I wonder if we can use standard copper tubing for this.

Someone I know wraps copper foil around solid wire, and after soldering 
trims it and pulls out the wire.  But in this case as well as the tube 
one, I don't like that there is no mechanical support, just the solder; 
compare that to the rivets.

The only version of this in the US I found is what I quoted at $80.  I 
didn't find any US distributor that has the exact UK parts, let alone 
the price.

"Stefan Trethan" <stefan_trethan@...> writes:
> And how much fun would it be to place 300 vias a board, manually?

More fun than soldering in 300 1/8" long wires.

> Also, with 300 vias a board you only get 3 boards out of your 1000
> pieces pack, for 15 pounds?

A thought I had... #30 wire wrapping wire is only 10 mils diameter; an
easy fit in a 13 mil hole.  If you can cut it so that the end is
essentially flat (or flat enough), what you do is turn the board
component side down on a flat surface and clamp/tape it down.  Then,
insert #30 wire into each via hole, solder, trim.  When you flip the
board over, the wires should be flush with the surface, and you may be
able to solder them to the pads with minimal bump-out.  Not sure if
it's flat enough for smd, but a copper braid may help to remove
excess.

I think if you have clearance issues under SMD parts, the solutions
could include (1) not putting vias there, or (2) pre-soldering all the
pads to raise the part up some.  Maybe smashing the #30 so it's
thinner might help too.  Or build a home electroless plating tank ;-)

On Fri, 08 Dec 2006 16:44:24 +0100, DJ Delorie <dj@...> wrote:

>
> A thought I had... #30 wire wrapping wire is only 10 mils diameter; an
> easy fit in a 13 mil hole.  If you can cut it so that the end is
> essentially flat (or flat enough), what you do is turn the board
> component side down on a flat surface and clamp/tape it down.  Then,
> insert #30 wire into each via hole, solder, trim.  When you flip the
> board over, the wires should be flush with the surface, and you may be
> able to solder them to the pads with minimal bump-out.  Not sure if
> it's flat enough for smd, but a copper braid may help to remove
> excess.


You should consider the reliability of such a joint.

ST

jpanhalt wrote:
> 
> Where did you find the rivets for $80/1000 in North America? I'm
> paying almost $30/100 at Circuit Technology (circuittechctr.com). John

http://www.lpkfusa.com/Store/ProductList.asp?Category=Through-Hole%20Plating%20-%20EasyContac

But for me $80 is still too much.  I want to pay an equivalent to the UK 
price.  If there's a Brit among the members planning to visit North 
America, make sure to bring some over :P

>Using pieces of wire, resistor legs, or header pins for hidden vias
>under surface mount parts; something I need to do often) is not
>really workable.

Very workable here. I do it all the time. However, To make a good 
solder joint with less than a 5 thou bump does require some practice 
and know-how. Those lacking the latter have deemed it impossible.

http://www.pbase.com/eldata/image/65408722

http://www.pbase.com/eldata/image/65448015

--- In Homebrew_PCBs@yahoogroups.com, "bobysgotguns" <bdt@...> wrote:
>

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

From: "DJ Delorie" <dj@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, December 08, 2006 3:44 PM
Subject: Re: [Homebrew_PCBs] Making hidden vias?


>
> "Stefan Trethan" <stefan_trethan@...> writes:
>> And how much fun would it be to place 300 vias a board, manually?
>
> More fun than soldering in 300 1/8" long wires.
>
>> Also, with 300 vias a board you only get 3 boards out of your 1000
>> pieces pack, for 15 pounds?
>
> A thought I had... #30 wire wrapping wire is only 10 mils diameter; an
> easy fit in a 13 mil hole.  If you can cut it so that the end is
> essentially flat (or flat enough), what you do is turn the board
> component side down on a flat surface and clamp/tape it down.  Then,
> insert #30 wire into each via hole, solder, trim.  When you flip the
> board over, the wires should be flush with the surface, and you may be
> able to solder them to the pads with minimal bump-out.  Not sure if
> it's flat enough for smd, but a copper braid may help to remove
> excess.
>
> I think if you have clearance issues under SMD parts, the solutions
> could include (1) not putting vias there, or (2) pre-soldering all the
> pads to raise the part up some.  Maybe smashing the #30 so it's
> thinner might help too.  Or build a home electroless plating tank ;-)

I try to avoid putting vias under SMD parts with homemade PCBs, but if I 
have to use them wire-wrap wire bent over doesn't cause too many problems 
provided I don't use too much solder.

Leon

Borislav Trifonov <bdt@...> writes:
> But for me $80 is still too much.  I want to pay an equivalent to
> the UK price.  If there's a Brit among the members planning to visit
> North America, make sure to bring some over :P

Have you tried calling these folks?
http://www.megauk.com/distributors/usa.php

I emailed him.  Hopefully he'll ship to Canada.


DJ Delorie wrote:

> 
> 
> 
> Borislav Trifonov <bdt@... <mailto:bdt%40shaw.ca>> writes:
>  > But for me $80 is still too much. I want to pay an equivalent to
>  > the UK price. If there's a Brit among the members planning to visit
>  > North America, make sure to bring some over :P
> 
> Have you tried calling these folks?
> http://www.megauk.com/distributors/usa.php 
> <http://www.megauk.com/distributors/usa.php>