Homebrew PCBs

OK folks, I have decided to take the plunge into building PCB's with SMD
components. I have been putting this off for about 3 years now, but the
availability of new parts in through hole configurations is undeniably
reducing.

Having watched many youtube videos, it seems the most important part of
the process is the flux, however, having never bought flux outside of flux
cored solder, I am at a loss for what I should be looking for in a flux.
It appears that while no-clean flux has the appeal of not needing a clean
up step, activated solder is easier to use. Should I be looking at a
liquid or paste flux?

I realize that there are probably as many opinions about this as there are
list members, but I would like to draw on the experience of the group and
hear suggestions...

Thanks

Anthony

I went with a $20 syringe of no clean solder paste. I find I can put adequately controlled dobs of paste on 0805,SOIC,SOT-23 pads by hand. The dobs merge together during soak anyway and then split back apart during reflow. It's neat to watch.

I use a skillet at 220 deg F for soak and a hot air gun for reflow. My buddy doesn't bother with the heat gun, he just cranks the temp all the way up on the skillet and gently lifts the board after reflow. Both methods seem to work fine, but both take a few tries to get comfortable with.  One day we'll make a toaster that does the whole profile thing.

Good luck!




--- In Homebrew_PCBs@yahoogroups.com, toftat@... wrote:

>
> OK folks, I have decided to take the plunge into building PCB's with SMD
> components. I have been putting this off for about 3 years now, but the
> availability of new parts in through hole configurations is undeniably
> reducing.
> 
> Having watched many youtube videos, it seems the most important part of
> the process is the flux, however, having never bought flux outside of flux
> cored solder, I am at a loss for what I should be looking for in a flux.
> It appears that while no-clean flux has the appeal of not needing a clean
> up step, activated solder is easier to use. Should I be looking at a
> liquid or paste flux?
> 
> I realize that there are probably as many opinions about this as there are
> list members, but I would like to draw on the experience of the group and
> hear suggestions...
> 
> Thanks
> 
> Anthony
>

My opinion is you should use plain old colophony resin flux. It
doesn't need cleaning in most circumstances and is very cheap and
reliable. And since it is a tree resin, it ought to be environmentally
friendly. You can dissolve it in a little methylated spirits for easy
application.

But you don't necessarily need flux for SMD work any more than for
throughhole work. I rarely use mine for SMD, mostly for tinning wires
and stuff. Solder wire or paste contains enough flux as it is. Only if
I change components very often using hot air and no fresh solder I add
flux.

ST

On Wed, Jul 7, 2010 at 8:11 PM,  <toftat@...> wrote:
> OK folks, I have decided to take the plunge into building PCB's with SMD
> components. I have been putting this off for about 3 years now, but the
> availability of new parts in through hole configurations is undeniably
> reducing.
>
> Having watched many youtube videos, it seems the most important part of
> the process is the flux, however, having never bought flux outside of flux
> cored solder, I am at a loss for what I should be looking for in a flux.
> It appears that while no-clean flux has the appeal of not needing a clean
> up step, activated solder is easier to use. Should I be looking at a
> liquid or paste flux?
>
> I realize that there are probably as many opinions about this as there are
> list members, but I would like to draw on the experience of the group and
> hear suggestions...
>
> Thanks
>
> Anthony
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>

I was sooo surprised how easy SMD is compared to how tough it looked.
The key to my success so far is to use *SOLDER  PASTE*.  Look for it
through google and/or Ebay. Pay attention to what you order because some
solder flux's are labeled "Solder Paste Flux". As I understand it, there
is liquid flux, flux paste (sticky flux) , and solder paste.  The solder
paste consist of a flux paste with tiny solder balls inside. I'm
currently using a solder paste from overseas. It's called something like
"Mechanics Solder Paste" and its model number is MCN-300. This stuff
rocks !  I've bought a few 50 gram jars, had my wife stuff some in a big
fat syringe and screw on a 19 gauge *blunt tip* needle. I remember
reading that the solder paste must be kept in the refrigerator while
not being used. I think it's something to do with the flux.

 

Also be sure to purchase a 20x - 45x  magnifier:
http://www.mpja.com/prodinfo.asp?number=17930+LN   

 

 

 and check out the guides on curiousinventor.com

 

 

 

 

Best Regards,

Steve Maroney

 

Business Computer Support, LLC

Mobile Phone:504-914-4704

Office Phone: 504-904-0266

Fax: 866-871-7797

From: Homebrew_PCBs@yahoogroups.com
[mailto:Homebrew_PCBs@yahoogroups.com] On Behalf Of toftat@...
Sent: Wednesday, July 07, 2010 1:12 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] Flux suggestions

 

  

OK folks, I have decided to take the plunge into building PCB's with SMD
components. I have been putting this off for about 3 years now, but the
availability of new parts in through hole configurations is undeniably
reducing.

Having watched many youtube videos, it seems the most important part of
the process is the flux, however, having never bought flux outside of
flux
cored solder, I am at a loss for what I should be looking for in a flux.
It appears that while no-clean flux has the appeal of not needing a
clean
up step, activated solder is easier to use. Should I be looking at a
liquid or paste flux?

I realize that there are probably as many opinions about this as there
are
list members, but I would like to draw on the experience of the group
and
hear suggestions...

Thanks

Anthony





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

On 07/07/2010 19:11, toftat@... wrote:
> OK folks, I have decided to take the plunge into building PCB's with SMD
> components. I have been putting this off for about 3 years now, but the
> availability of new parts in through hole configurations is undeniably
> reducing.
>
> Having watched many youtube videos, it seems the most important part of
> the process is the flux, however, having never bought flux outside of flux
> cored solder, I am at a loss for what I should be looking for in a flux.
> It appears that while no-clean flux has the appeal of not needing a clean
> up step, activated solder is easier to use. Should I be looking at a
> liquid or paste flux?
>
> I realize that there are probably as many opinions about this as there are
> list members, but I would like to draw on the experience of the group and
> hear suggestions...

I use solder with a no-clean flux core, but the flux isn't very active. 
I coat the pads with additional no-clean flux using a flux pen. It seems 
more active than the stuff in the solder. For drag-soldering fine-pitch 
devices I use Warton Metals' jelly flux, it comes in a convenenient syringe.

Leon
-- 
Leon Heller
G1HSM