I either use 64-035 .015 diameter "silver bearing solder" from Radio Shack, or Kester no wash paste. My favorite
wick is Tech-Spray 1809-10F but most any good super fine wick will do. I also use a small butane torch to remove most
SMT components. Once you get the hang of it it's easy to pop off a 100+ pin flat pack with the torch and reuse it or
the board it came from. I've got a Hakko hot air wand but never use it. I prefer the torch. I hardly ever remove the flux
on a board. Never had any problems even in harsh and moist environments. For commercial stuff I have them assembled
and conformal coated for industrial environments. When I do remove flux it's usually with standard rubbing alcohol or some
Denatured alcohol.
I tried one of those Intel Play USB microscopes for a while. The delay between moving something under it and it showing
up on the monitor was to slow to be useable.
Yes the SMT microscopes are stereo. I can't imagine using a mono microscope.
I use a Hakko 703 solder station at home with a Hakko 493 smoke sucker. Most of the stuff at work is Metcal which is ok
I just prefer the Hakko gear.
I've never had any problems with pinholes using the Press N Peel blue and an HP 2100 laserjet. Before that I used it with an
NEC 850 laser and that also worked fine. I've done several transparencies on an HP 1000C inkjet, an Epson 1520 and now the Epson C80.
Also no problems with any of them. The C80 will do finer traces than the older printers would but I still prefer the laser for either photo
or iron on.
I did mechanical etching for years with a big CNC router I have but have gone on to smaller and smaller parts that routing traces for
just won't work. Or I guess I should say the industry is dragging me kicking and screaming to smaller and smaller parts.
The first PC board I ever made was done with rub on transfers and all hand routing. Now I use high end EDA tools and board shops
or the limited complexity double sided boards at home.
later,
Larry E.
----- Original Message -----
From: dg140@...
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, September 12, 2002 8:38 PM
Subject: Re: [Homebrew_PCBs] making SMT boards
Hi Larry. Interesting work. Do you find that the Laser printer leaves
tiny holes in the foil pattern?
Which solder gauge do you use for SMT (and copper wick if used for
desoldering)?
My hands are now increasingly unsteady because of an undiagnosed muscle
tic, so my precision tinkering days are over for now. The actual assembly
work and repair work I can send out to a friend, and we share the returns.
He simply follows my instructions. Being blind, I would use a small
stainless steel needle to solder when I worked on PCBS; solder would be
fed through the needle to the work, and I'd follow the needle to the work
with the iron. A very good system (not my idea), and completely
successful. It is irnonic that I, a blind person, must now buy a
magnifying device.
Do you find that cleaning flxu from boards does any damage, or is it no
problem? I've heard of everything being used to clean. Some use ethanal,
others acetone, or distilled water and mild dish soap, or electrosolve. What
do folks use on list to clean any excess flux?
Charles
--
>I've been doing surface mount for many years.
>
>Until the last year or so, I've been able to do without a microscope. But now, my eyes have started the process of
>decreasing near vision. Super small stuff, I just can't get close enough to focus on anymore.
>
>I had been using standard reading glasses you can get at the discount stores. Get the highest magnification
>pair that you can wear without getting dizzy. You would be surprised just how much you can do with just those.
>
>I picked up a great Meiji microscope off Ebay for $600. Now that might sound like a lot, but it's at least a $4000 setup.
>
>I've always had access to microscopes at work, but now I have one in my home shop as well. It really makes a difference.
>
>I can readily do 6 mil traces on 6 mil spaces with Press N Peel Blue or positive photoresist boards and an HP laser printer.
>I've done 5 on 5 but had to hand touch up too many traces. 8 x 8 is a very easy range to hit. Once you start working 6 x 6
>the typical 10 by 10 starts looking BIG! ( these are trace widths and spaces between traces )
>
>I use a .010 drill and Kynar wire wrap wire to bring vias across the two sides. Components that have through hole leads can
>be soldered on both sides with solder paste and small stand off spacer. Flush cutting pliers even let you put vias under
>IC's. Just cut the solder bumps off as close as you can to the board.
>
>TQFP packages are very easy with a microscope or just reading glasses if you use solder paste and a toaster oven to reflow
>the board.
>
>BGA packages are also easy to do. Just use good flux and the toaster oven to reflow them. But solder mask really is needed
>to keep bridging from happening with BGA's. So those boards really need to be sent out to have the blank boards made with
>a good solder mask applied. Most BGA designs will need more than two sides anyway and the escape routing can be a pain even
>on 4 layers. I don't try to make more than 2 layer boards in the home shop.
>
>I usually hand solder all my surface mount boards. If there's a lot of components I'll put all the parts on with paste and
>toaster oven reflow them.
>
>later,
>Larry E.
>
>
>
> ----- Original Message -----
> From: dg140@...
> To: homebrew_pcbs@yahoogroups.com
> Sent: Wednesday, September 11, 2002 11:38 PM
> Subject: [Homebrew_PCBs] making SMT boards
>
>
> Anyone etched surface-mount technology PCBs? How did it go? Simply
> soldering the odd component or touching up an IC or small part seems
> difficult enough. YOu'd think I could find a cheap microscope with all of
> the high tech companies closing and moving herre in Ottawa, but no such
> fortune so far.
>
> Charles
>
>
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