Homebrew PCBs

How do folks here tin their boards after they're etched?

tnx
jim

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

On Sun, 20 Nov 2005 18:54:47 +0100, Jim Miller <jim@...> wrote:

> How do folks here tin their boards after they're etched?
>
>
> tnx
>
> jim


There was a discussion about using paint-on plumbers soldering paste a  
while ago, which works really well i must say.

ST

Hi,

while we are at the subject, i want to buy some paste for this  
application. I have tried it with old (lead) paste and it works well, but  
i don't feel comfortable with the disposal problem (as some of the paste  
is washed off). Also i hope for a nicer finish with tin paste.

I have the choice of:

ROSOL 1S S-Sn96,Ag4 250g 15eur

ROSOL 3 S-Sn97,Cu3 250g 10eur

Now what is the difference between paste with copper and paste with  
silver? I don't really mind the price since it will go a long way.
I remember some leadfree solder (wire) has silver in it too?

Anyone doing the tinning, what paste is yours?

Thanks!

ST

I use Tinnit. The only drawback is having to keep it warmer than 120 deg. F 
in use. It precipitates into a white goo when it's cold.

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

From: "Jim Miller" <jim@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, November 20, 2005 11:54 AM
Subject: [Homebrew_PCBs] Tinning the board?


> How do folks here tin their boards after they're etched?

Now I'm really curious if you can just stick on the SMT packages at the same 
time. Would you use that paste without a solder mask? just slather it on 
like peanut butter?

Here's a link to some SynTech products. It's not nearly as pricey as I 
thought it would be.

http://www.stencilsunlimited.com/solder_products.php?source=google


----- Original Message ----- 
From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, November 20, 2005 12:44 PM
Subject: [Homebrew_PCBs] Tinning the board? silver/tin solder or copper/tin 
solder?

> Hi,
>
> while we are at the subject, i want to buy some paste for this
> application. I have tried it with old (lead) paste and it works well, but
> i don't feel comfortable with the disposal problem (as some of the paste
> is washed off). Also i hope for a nicer finish with tin paste.
>
> I have the choice of:
>
> ROSOL 1S S-Sn96,Ag4 250g 15eur
>
> ROSOL 3 S-Sn97,Cu3 250g 10eur

On Sun, 20 Nov 2005 20:05:59 +0100, Mike Young <mikewhy@...>  
wrote:

> Now I'm really curious if you can just stick on the SMT packages at the  
> same
>
> time. Would you use that paste without a solder mask? just slather it on
>
> like peanut butter?
>
>
> Here's a link to some SynTech products. It's not nearly as pricey as I
>
> thought it would be.
>
>
> http://www.stencilsunlimited.com/solder_products.php?source=google



That's really rather cheap, compared to the usual prices for SMD paste  
sold in syringes.

I'm not sure about the smd at the same time, you want to wash off the  
paste that was painted on the etched parts after reflow. So if you already  
have SMDs there it might be impossible to get it out from under them. With  
the smaller parts it would probably wick away, but with the larger ones  
probably not. Anyway you need to make larger "mounds" on the smd pads, so  
you don't really add work if you make it in two stages.


What i currently wonder about is component legend. Not sure if i can  
transfer on solder, but i guess so.

ST

jim- read message 10103- the dealer is mcmaster.com
mebo


--- Jim Miller <jim@...> wrote:

> How do folks here tin their boards after they're
> etched?
> 
> tnx
> jim
> 
> [Non-text portions of this message have been
> removed]
> 
> 



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

From: "Stefan Trethan" <stefan_trethan@...>
> I have the choice of:
>
> ROSOL 1S S-Sn96,Ag4 250g 15eur
>
> ROSOL 3 S-Sn97,Cu3 250g 10eur
>
> Now what is the difference between paste with copper and paste with
> silver? I don't really mind the price since it will go a long way.
> I remember some leadfree solder (wire) has silver in it too?

It's too late in the day for hard science, but here's the reader's digest 
version. Eutectic tin (liquidus, or molten, that is) alloys freely with many 
metals, including silver. Adding silver to the solder reduces the silver 
taken from the solderee in the intermetallic layer formed during soldering. 
Sn96Ag4 also melts at a higher temperature than Sn63Pb37. This is useful for 
reflowing boards with components on both sides. The first side is reflowed 
at a high temp profile using tin/silver. The second side is then populated 
and reflowed with a suitable paste on a lower temp profile. If lead-free is 
a concern (one presumes it is), tin/copper melts about 20^C lower than 
tin/silver, 220^C versus 240^C; tin/bismuth/silver is lower still. The more 
familiar tin/lead melts at about 180^C, much lower than any of the lead-free 
alloys.

Since the mechanical or electrical properties aren't the major concern for 
choosing between the two, tin/copper would work as well or better than 
tin/silver for our use. For that matter, I'm still using Kester 44. Just 
ordered another 1/2 lb., in fact. Nothing wets as well as that old crap.

> > I have the choice of:
> >
> > ROSOL 1S S-Sn96,Ag4 250g 15eur
> >
> > ROSOL 3 S-Sn97,Cu3 250g 10eur
> >
> > Now what is the difference between paste with copper and paste with
> > silver? I don't really mind the price since it will go a long way.
> > I remember some leadfree solder (wire) has silver in it too?
> 

Apart from the melting points, one of the things that has me really
concerned is tin pest. For most projects its probably not a big issue,
as few will see the outdoors or temperatures much below room
temperature. I would tend to think that either of those solders would
be subject to failure if exposed to low temperature (below 13 deg C)
due to tin pest. The silver version might be a bit better than the tin
copper version.

Ron

In a message dated 11/20/2005 12:21:12 P.M. Central Standard Time,  
jim@... writes:

How do  folks here tin their boards after they're etched?<<
 
Normally, one "tins" the desired pattern on the copper, then  uses an etchant 
that attacks copper, but NOT tin/lead, so the pre-tinned tracks  and pads 
stay.  But a solution made of a solid called "Tinnit" by one of  the mailorder 
PCB-stuff firms will "electrolessly tin" ANY copper dipped in it  (per 
instructions).  I do NOT know how the pro-houses "solder-plate" the  pattern on bare 
copper, if this is electroless or done with DC power.   Somebody?







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

Tinnit. Works fine, is simple, and cheap. About 4 bucks.

Hope this helps,

Ballendo

P.S. Circuit Specialists sells it; among many others.

--- In Homebrew_PCBs@yahoogroups.com, "Jim Miller" <jim@j...> wrote:

>
> How do folks here tin their boards after they're etched?
> 
> tnx
> jim
> 
> [Non-text portions of this message have been removed]
>

Hello to All,
   
  How can I create a mechanically etch style PCB?
  Can I do this using eagle?
   
  I'm still going to use Ferric Chloride  to etch it, but I want the mechanically etch style... any recommendations or suggestions?
   
  More power to this group.

		
---------------------------------
 Yahoo! FareChase - Search multiple travel sites in one click.  

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

On Mon, 21 Nov 2005, Ron wrote:

> Apart from the melting points, one of the things that has me really
> concerned is tin pest. For most projects its probably not a big issue,
> as few will see the outdoors or temperatures much below room
> temperature. I would tend to think that either of those solders would
> be subject to failure if exposed to low temperature (below 13 deg C)
> due to tin pest. The silver version might be a bit better than the tin
> copper version.

Tin whiskers also concern me, especially as more of us delve into
surface-mount components for our homebrews.

-- 
David Griffith
dgriffi@...

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

From: <JanRwl@...>
> instructions).  I do NOT know how the pro-houses "solder-plate" the 
> pattern on bare
> copper, if this is electroless or done with DC power.   Somebody?

Reading Think and Tinker's gives one the notion they can do this (almost) 
easily at home. Plating is deposited by electroplating at about 20A/sq.ft. 
Copper, bright tin, and solder are the typical platings, and differ only in 
the anode bars and electrolyte. For the small boards that I do, I think I 
can easily manage a DC supply to source 5A into the 20'ish milliohms in the 
bath.

Some evening this week, I think I'll have a walkabout through WalMart and 
see what tubs are easily available for making into plating baths. I think a 
wallpaper wetting trough might be too long, but perhaps there'll be 
something the right size in the garden center. Actually, a rectangular 
tupperware thing with a tight fitting lid will be ideal, I think.

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

From: <pinoy_nyc@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, November 20, 2005 11:46 PM
Subject: [Homebrew_PCBs] Mechanically Etch Style


>  How can I create a mechanically etch style PCB?
>  Can I do this using eagle?
>
>  I'm still going to use Ferric Chloride  to etch it, but I want the 
> mechanically etch style... any recommendations or suggestions?

Isolation etching? Dunno. Some of the guys reported doing so with Proteus. 
Do let me know if you find out how to do this in Eagle.

Hi Mike,
   
  Oh I see, it's isolation etching. Thanks.
   
  I just tried experimenting with photoshop and able to produce it Isolation etching in
  about 30 seconds from the original eagle board image.
  what I did is select all the non copper area (black color) and contract the selection
  into 8 pixels. by doing Select->Modify->Contract and the flooding the selection with
  white.  It looks ok though...
   
  I'm sure somebody has tried this before, and they may have a better idea.
   
  

Mike Young <mikewhy@...> wrote:

  ----- Original Message ----- 
From: <pinoy_nyc@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Sunday, November 20, 2005 11:46 PM
Subject: [Homebrew_PCBs] Mechanically Etch Style


>  How can I create a mechanically etch style PCB?
>  Can I do this using eagle?
>
>  I'm still going to use Ferric Chloride  to etch it, but I want the 
> mechanically etch style... any recommendations or suggestions?

Isolation etching? Dunno. Some of the guys reported doing so with Proteus. 
Do let me know if you find out how to do this in Eagle. 



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

Excellent! Post process the image. :) I'll give the magic wand a swing or 
two this evening, too.

8 pixels is probably just right for 600 dpi, a touch more than 13 mil. I 
might go a bit more generous on the bus side.

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

From: <pinoy_nyc@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, November 21, 2005 8:56 AM
Subject: Re: [Homebrew_PCBs] Mechanically Etch Style


> Hi Mike,
>
>  Oh I see, it's isolation etching. Thanks.
>
>  I just tried experimenting with photoshop and able to produce it 
> Isolation etching in
>  about 30 seconds from the original eagle board image.
>  what I did is select all the non copper area (black color) and contract 
> the selection
>  into 8 pixels. by doing Select->Modify->Contract and the flooding the 
> selection with
>  white.  It looks ok though...

Here's the procedure using Photoshop
  1.) Load the board image
2.) select magic wand - make sure anti-alias & contigous is disabled.
3.) click/select the black color (non copper area)
    this will select all the black color since contigous option is disabled.
4.) contract the selection/marque to 5 pixels. 
    From Menu: Select->Modify->Contract, then choose 5.
5.) Hit del key, to delete the selection/marque.
6.) Now etch the PCB with your favorite solution.
  
 
   
   
  STEP 1.) *** THE ORIGINAL BOARD FROM EAGLE ****
  

   
  STEP 4.) **** LOADED INTO PHOTOSHOP, MARQUE SELECTED AND CONTRACTED TO 5 PIXELS ***
  
   
   
  STEP 5.) *** DONE!!!! *** ISOLATED TRACES READY TO BE ETCH ***
   
    

   
   
   
   
  
Mike Young <mikewhy@...> wrote:
  Excellent! Post process the image. :) I'll give the magic wand a swing or 
two this evening, too.

8 pixels is probably just right for 600 dpi, a touch more than 13 mil. I 
might go a bit more generous on the bus side.

----- Original Message ----- 
From: <pinoy_nyc@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, November 21, 2005 8:56 AM
Subject: Re: [Homebrew_PCBs] Mechanically Etch Style


> Hi Mike,
>
>  Oh I see, it's isolation etching. Thanks.
>
>  I just tried experimenting with photoshop and able to produce it 
> Isolation etching in
>  about 30 seconds from the original eagle board image.
>  what I did is select all the non copper area (black color) and contract 
> the selection
>  into 8 pixels. by doing Select->Modify->Contract and the flooding the 
> selection with
>  white.  It looks ok though...



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

WOOT!... the 3 images didn't attached succesfully... 
  I've uploaded the 3 images, pls see
   
  Photo Section - ISOLATED ETCHING - TIPS & TRICKS
   
   - PHOTO SECTION LINK - 
   
   
  

"pinoy_nyc@..." <pinoy_nyc@...> wrote:
  Here's the procedure using Photoshop
  1.) Load the board image
2.) select magic wand - make sure anti-alias & contigous is disabled.
3.) click/select the black color (non copper area)
    this will select all the black color since contigous option is disabled.
4.) contract the selection/marque to 5 pixels. 
    From Menu: Select->Modify->Contract, then choose 5.
5.) Hit del key, to delete the selection/marque.
6.) Now etch the PCB with your favorite solution.
  

   
   
  STEP 1.) *** THE ORIGINAL BOARD FROM EAGLE ****
  

   
  STEP 4.) **** LOADED INTO PHOTOSHOP, MARQUE SELECTED AND CONTRACTED TO 5 PIXELS ***
  
   
   
  STEP 5.) *** DONE!!!! *** ISOLATED TRACES READY TO BE ETCH ***
   
    

   
   
   
   
  
Mike Young <mikewhy@...> wrote:
  Excellent! Post process the image. :) I'll give the magic wand a swing or 
two this evening, too.

8 pixels is probably just right for 600 dpi, a touch more than 13 mil. I 
might go a bit more generous on the bus side.

----- Original Message ----- 
From: <pinoy_nyc@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, November 21, 2005 8:56 AM
Subject: Re: [Homebrew_PCBs] Mechanically Etch Style


> Hi Mike,
>
>  Oh I see, it's isolation etching. Thanks.
>
>  I just tried experimenting with photoshop and able to produce it 
> Isolation etching in
>  about 30 seconds from the original eagle board image.
>  what I did is select all the non copper area (black color) and contract 
> the selection
>  into 8 pixels. by doing Select->Modify->Contract and the flooding the 
> selection with
>  white.  It looks ok though...



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  SPONSORED LINKS 
        Electrical engineering degree online   Electrical engineering degree   Printed circuit board     Electrical engineering   Electrical engineering course   Electrical engineering graduate school 
    
---------------------------------
  YAHOO! GROUPS LINKS 

    
    Visit your group "Homebrew_PCBs" on the web.
    
    To unsubscribe from this group, send an email to:
Homebrew_PCBs-unsubscribe@yahoogroups.com
    
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[Non-text portions of this message have been removed]



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

On Tue, 22 Nov 2005 04:57:40 +0100, pinoy_nyc@...  
<pinoy_nyc@...> wrote:

>  WOOT!... the 3 images didn't attached succesfully...
>
>   I've uploaded the 3 images, pls see
>
>
>   Photo Section - ISOLATED ETCHING - TIPS & TRICKS
>
>
>    - PHOTO SECTION LINK -
>


That's a cool way of making a copper pour, not every PCB software can do  
it and it might be a solotion for those...

ST

--- In Homebrew_PCBs@yahoogroups.com, "Jim Miller" <jim@j...> wrote:
>
> How do folks here tin their boards after they're etched?
> 
> tnx
> jim
> 
> [Non-text portions of this message have been removed]

Years ago, I used to use an electroless Tin plating solution 
based on Stannous Chloride, Sodium Hydroxide, and Sodium Cyanide.
It produced a beautiful plating, but was a bit of a pain to work
with.  If you left it exposed to air, it would oxidize fairly
quickly.  If you splashed in a bit of acid, it would evolve
Cynaide gas, which would rapidly kill everyone in the room.
If you didn't have the temperature quite right, it wouldn't 
give you a good plating.

I've since given up on it, and usually just solder the boards
now.

Dave

On Tue, 22 Nov 2005 16:40:51 +0100, Dave <wa4qal@...> wrote:

> Years ago, I used to use an electroless Tin plating solution
>
> based on Stannous Chloride, Sodium Hydroxide, and Sodium Cyanide.
>
> It produced a beautiful plating, but was a bit of a pain to work
>
> with.  If you left it exposed to air, it would oxidize fairly
>
> quickly.  If you splashed in a bit of acid, it would evolve
>
> Cynaide gas, which would rapidly kill everyone in the room.
>
> If you didn't have the temperature quite right, it wouldn't
>
> give you a good plating.
>
>
> I've since given up on it, and usually just solder the boards
>
> now.
>
>
> Dave
>


The current electroless solutions aren't that much better, containing  
thiurea which is a known carcinogenic substance.

ST