[sdiy] Moving to Surface Mount - lots of questions

[Mike Beauchamp]

Thanks Tom,
seems like the next big project might be a good time to take the
plunge into SMT.

Mike


On Tue, Dec 6, 2011 at 9:13 PM, Tom Arnold <xyzzy at sysabend.org> wrote:
> On Tue, Dec 06, 2011 at 02:45:09AM -0500, Mike Beauchamp wrote:
>> after assembling a few PCB's with a few hundred resistors, I've been
>> thinking about moving to Surface Mount for my next project. Please
>> convince me, or talk me out of it :)
>
> I can manually stuff a board with 1206 resistors using a soldering iron with
> a small tip much faster then I can stuff through hole.  Enough so that I'm
> slowly switching in that direction.  The large parts are quite easy to deal
> with.  I touch the pad with solder, nail one end of the part down, then hit
> the other end.  no fliping and trimming, no worries about leveling the parts
> when I'm stuffing a bunch of parts between solder passes.  At the very least
> I'd try that.  I think you'd be surprised how easy it is.
>
>> Speed: Having never done it before, how much faster is it to
>> stencil-place-oven as opposed to insert-solder-clip?
>
> Its at least on par if not faster to do the SMD parts.
>
>> Reliability: I know that repairing a through-hole board is easier for
>> most people, but is the reliability of SMT stuff on par with TH?
>
> Seems to be the same.  Rework is a little more difficult but only because I
> havent had enough failures to really get good at it.
>
>> Storage: Those SMD resistors are tiny! What are some good ways to
>> store 30-40 different values so they can easily be grabbed for
>> populating?
>
> I buy reels.  Usually find the values I want for a few dollars a reel
> surplus.  I havent found a great method for storing small quantities.  Right
> now I use little plastic bags in a compartmented plastic box.
>
>> Toxicity: Soldering irritates my asthma, although my fume extractor
>> helps heaps. Does sticking solder paste into an oven cause similar
>> fumes?
>
> I would not use your home oven.  At the very least a cheap toaster oven you
> can run in the garage.  I've been using the skillet method.  If you just
> place the board in an electric skillet you can heat it up quite nicely.
> http://www.sparkfun.com/tutorials/59
>
> With the skillet method you can use your normal smoke filter.
>
> I've done BGAs with the skillet method.  Lots of fun to place several
> hundred little solder balls by hand...
>
> --
>  -----------------------------------------------------------------
>  - Tom Arnold       -  Free Synth DIY webspace http://www.sdiy.org
>  - SynthGeek        -  "...is it a virus, a drug, or a religion?"
>  - K6AET            -  Juanita Shrugs. "What's the difference?
>  --------------------         -- Neal Stephenson,  Snow Crash
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-- 
[mike]