Hey all, poor EE student here.

I recently bought a cheap hot air rework station, and have been
harvesting all the useable SMD IC's from old boards which I have been
hoarding since the mid-80's.

Anyway, I can pull a typical IC in about 3 seconds, I am using a small
round tip with medium air pressure, 350 degree C air temp.

TWO Questions:

1) I have tested quite a few of the logic IC's and they seem fine
after removal, what are the chances that I have done some heat-related
damage and they will fail while I am using them to build random non-
critical projects?

2) I have scoured the internet and can't find a source for SMD/DIP
storage tubes. I would like to put them in clear ESD-safe storage
tubes for easy index/location, but can't seem to find any!

Thanks in advance,

Jake

Jake wrote in message
...
Hey all, poor EE student here.

I recently bought a cheap hot air rework station, and have been
harvesting all the useable SMD IC's from old boards which I have been
hoarding since the mid-80's.

Anyway, I can pull a typical IC in about 3 seconds, I am using a small
round tip with medium air pressure, 350 degree C air temp.

TWO Questions:

1) I have tested quite a few of the logic IC's and they seem fine
after removal, what are the chances that I have done some heat-related
damage and they will fail while I am using them to build random non-
critical projects?

2) I have scoured the internet and can't find a source for SMD/DIP
storage tubes. I would like to put them in clear ESD-safe storage
tubes for easy index/location, but can't seem to find any!

Thanks in advance,

Jake


Once a year or so I sort my years collection of similarly salvaged ICs on
leading first 2 digits. I use standard clear celluloid tubes, for storage,
that I've added a stripe of that window foil gummmed Al tape along each tube
for ESD purposes.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

On Sun, 27 Sep 2009 10:15:02 -0700 (PDT), Jake
wrote:

Hey all, poor EE student here.

I think the correct term is starving student.

I recently bought a cheap hot air rework station, and have been
harvesting all the useable SMD IC's from old boards which I have been
hoarding since the mid-80's.

Anyway, I can pull a typical IC in about 3 seconds, I am using a small
round tip with medium air pressure, 350 degree C air temp.

I used to do that clamping one end of the board in a vice, heating the
board with a propane torch, pulling back on the board, and launching
the components (and solder blobs) in the opposite direction. It
worked amazingly well, even for through hole components.

1) I have tested quite a few of the logic IC's and they seem fine
after removal, what are the chances that I have done some heat-related
damage and they will fail while I am using them to build random non-
critical projects?

Fairly small. 3 seconds at 350C isn't going to do much. You can
probably do some damage is you overheat, or thermal shock the parts,
but in general, they should survive. Whether the original components
are any good is subject to some speculation. After 20 years, you'll
start to see the effects of package leakage, vibration, broken wire
bonds, water incursion, etc. I suggest you use IC sockets on your
random non-critical projects.

2) I have scoured the internet and can't find a source for SMD/DIP
storage tubes. I would like to put them in clear ESD-safe storage
tubes for easy index/location, but can't seem to find any!

Google finds hundreds of hits under "IC tubes" and "package carriers".
For example:
http://store.staticspecialists.com/ictubeshippers.aspx

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Fairly small. *3 seconds at 350C isn't going to do much. *You can
probably do some damage is you overheat, or thermal shock the parts,
but in general, they should survive. *Whether the original components
are any good is subject to some speculation. *After 20 years, you'll
start to see the effects of package leakage, vibration, broken wire
bonds, water incursion, etc. *I suggest you use IC sockets on your
random non-critical projects.

Excellent, thanks for the advice. Most of the boards I am harvesting
from are old computer-related boards that were never used, or were
used very little. I have had many jobs in the IT industry and used to
snatch up any old (but new or nearly new) equipment I saw, regardless
of whether I needed it or not


Google finds hundreds of hits under "IC tubes" and "package carriers".
For example:
http://store.staticspecialists.com/ictubeshippers.aspx

Thanks, Jeff. I honestly can't explain why I didn't find any when
looking before, I think I was using the search term "ESD storage
tubes" maybe that was the reason!

Thanks again.

Fairly small. *3 seconds at 350C isn't going to do much. *You can
probably do some damage is you overheat, or thermal shock the parts,
but in general, they should survive. *Whether the original components
are any good is subject to some speculation. *After 20 years, you'll
start to see the effects of package leakage, vibration, broken wire
bonds, water incursion, etc. *I suggest you use IC sockets on your
random non-critical projects.

Excellent, thanks for the advice. Most of the boards I am harvesting
from are old computer-related boards that were never used, or were
used very little. I have had many jobs in the IT industry and used to
snatch up any old (but new or nearly new) equipment I saw, regardless
of whether I needed it or not


Google finds hundreds of hits under "IC tubes" and "package carriers".
For example:
http://store.staticspecialists.com/ictubeshippers.aspx

Thanks, Jeff. I honestly can't explain why I didn't find any when
looking before, I think I was using the search term "ESD storage
tubes" maybe that was the reason!

Thanks again.

Jake wrote:

Hey all, poor EE student here.

I recently bought a cheap hot air rework station, and have been
harvesting all the useable SMD IC's from old boards which I have been
hoarding since the mid-80's.

Anyway, I can pull a typical IC in about 3 seconds, I am using a small
round tip with medium air pressure, 350 degree C air temp.

TWO Questions:

1) I have tested quite a few of the logic IC's and they seem fine
after removal, what are the chances that I have done some heat-related
damage and they will fail while I am using them to build random non-
critical projects?

2) I have scoured the internet and can't find a source for SMD/DIP
storage tubes. I would like to put them in clear ESD-safe storage
tubes for easy index/location, but can't seem to find any!

Thanks in advance,

Jake

I just put mine in small paper bags ! The type used for confectionary
about 4" x 6".

--
Best Regards:
Baron.

"Jake" wrote in message
...
Hey all, poor EE student here.

I recently bought a cheap hot air rework station, and have been
harvesting all the useable SMD IC's from old boards which I have been
hoarding since the mid-80's.

Anyway, I can pull a typical IC in about 3 seconds, I am using a small
round tip with medium air pressure, 350 degree C air temp.

TWO Questions:

1) I have tested quite a few of the logic IC's and they seem fine
after removal, what are the chances that I have done some heat-related
damage and they will fail while I am using them to build random non-
critical projects?

2) I have scoured the internet and can't find a source for SMD/DIP
storage tubes. I would like to put them in clear ESD-safe storage
tubes for easy index/location, but can't seem to find any!

Thanks in advance,

Jake

I usually leave stuff on the board until I need it. It is too easy to lose
or damage off the board. Most stuff is protected as long as it is on the
board. Besides it takes too much labor and materials to deal with many
devices that no one needs for few that are worthwhile. It is good practice
for rework though.

On Tue, 29 Sep 2009 01:12:21 +1000, Bob Larter
wrote:

I stick mine on sheets of Velostat (black, conductive) foam, cut to fit
my parts drawers. It seems to work okay.

Bad idea. I did the same thing in the 1970's and 80's. Much later,
when I pulled out the IC's, the leads were gone. What happened is
that the foam absorbed moisture from the air, held onto it, and slowly
corroded the leads. In addition, some of the black foam deteriorated
into a crumbly mess. There are apparently different types (neoprene,
polyethylene, etc) of foam.

Black conductive foam is probably adequate for storing IC's for a few
years, but as I discovered, not for 20-30 years.

There was an article on the topic in May 1992 QST titled "Black
Conductive Component-Protection Foam Damages Parts (Mitchell): Feb, p.
75". If interested, I'll see if I can download or find a copy.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

In article
,
Jake wrote:
I recently bought a cheap hot air rework station, and have been
harvesting all the useable SMD IC's from old boards which I have been
hoarding since the mid-80's.

Respect. The idea of using SMD bits for home projects makes me sweat. ;-)

--
*Gaffer tape - The Force, light and dark sides - holds the universe together*

Dave Plowman London SW
To e-mail, change noise into sound.

On Tue, 29 Sep 2009 15:40:25 +1000, Bob Larter
wrote:

Jeff Liebermann wrote:
On Tue, 29 Sep 2009 01:12:21 +1000, Bob Larter
wrote:

I stick mine on sheets of Velostat (black, conductive) foam, cut to fit
my parts drawers. It seems to work okay.

Bad idea. I did the same thing in the 1970's and 80's. Much later,
when I pulled out the IC's, the leads were gone. What happened is
that the foam absorbed moisture from the air, held onto it, and slowly
corroded the leads. In addition, some of the black foam deteriorated
into a crumbly mess. There are apparently different types (neoprene,
polyethylene, etc) of foam.

Black conductive foam is probably adequate for storing IC's for a few
years, but as I discovered, not for 20-30 years.

There was an article on the topic in May 1992 QST titled "Black
Conductive Component-Protection Foam Damages Parts (Mitchell): Feb, p.
75". If interested, I'll see if I can download or find a copy.

Please do, I'd be interested in reading it.

See:
http://802.11junk.com/jeffl/crud/QST_Feb_1992_p75.pdf
If you don't believe it, I have my pile rotting foam and rusted IC's
in the closet. I'll post a photo when (and if) I recover from my
latest culinary disaster.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote in message
...
On Tue, 29 Sep 2009 01:12:21 +1000, Bob Larter
wrote:

I stick mine on sheets of Velostat (black, conductive) foam, cut to fit
my parts drawers. It seems to work okay.

Bad idea. I did the same thing in the 1970's and 80's. Much later,
when I pulled out the IC's, the leads were gone. What happened is
that the foam absorbed moisture from the air, held onto it, and slowly
corroded the leads. In addition, some of the black foam deteriorated
into a crumbly mess. There are apparently different types (neoprene,
polyethylene, etc) of foam.

Black conductive foam is probably adequate for storing IC's for a few
years, but as I discovered, not for 20-30 years.

There was an article on the topic in May 1992 QST titled "Black
Conductive Component-Protection Foam Damages Parts (Mitchell): Feb, p.
75". If interested, I'll see if I can download or find a copy.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

seconded
This is my experience, from my tips files. When I ran a shop I had the
example of this hanging up, 0.1 inch spaced rust marks in the foam
and ICs with rusted through legs

Note of caution for long-term storage of ICs
Some black conductive foam is hygroscopic in the long term and can
cause complete corrosion of the legs of ICs and trannies etc in an
ordinary storage situation ,not necessarily a damp garden shed.


The storage I use is 6 inch long x 1 inch diameter clear celluloid tubes
with polythene lids
I was lucky to be the only bidder for one lot in an auction , it was 5,000
unused tubes with lids. If you go into a habberdashers they always seem to
be used for storing buttons, ask someone there, where they get them from. As
I said with a strip of Al stuck along each one seems good enough for ESD


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

On Mon, 28 Sep 2009 23:22:47 -0700, Jeff Liebermann
wrote:

See:
http://802.11junk.com/jeffl/crud/QST_Feb_1992_p75.pdf
If you don't believe it, I have my pile rotting foam and rusted IC's
in the closet. I'll post a photo when (and if) I recover from my
latest culinary disaster.

Here's an example. My guess is about 15 years in the back of the
closet. I'll confess to having a roof leak about 10 years ago, which
may have aggravated the problem:
http://www.11junk.com/pics/drivel/slides/black-foam-rust.html

I don't have a sample of the foam that crumbled. Just visualize the
black foam turning to anything between dust and crumbs when moved.


--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote in
:

On Mon, 28 Sep 2009 23:22:47 -0700, Jeff Liebermann
wrote:

See:
http://802.11junk.com/jeffl/crud/QST_Feb_1992_p75.pdf
If you don't believe it, I have my pile rotting foam and rusted IC's
in the closet. I'll post a photo when (and if) I recover from my
latest culinary disaster.

Here's an example. My guess is about 15 years in the back of the
closet. I'll confess to having a roof leak about 10 years ago, which
may have aggravated the problem:
http://www.11junk.com/pics/drivel/slides/black-foam-rust.html

I don't have a sample of the foam that crumbled. Just visualize the
black foam turning to anything between dust and crumbs when moved.



you need to use some silica gel packs to remove the moisture from the
containers.

--
Jim Yanik
jyanik
at
localnet
..com

On Tue, 29 Sep 2009 22:21:46 -0500, Jim Yanik
wrote:

Jeff Liebermann wrote in
:
Here's an example. My guess is about 15 years in the back of the
closet. I'll confess to having a roof leak about 10 years ago, which
may have aggravated the problem:
http://www.11junk.com/pics/drivel/slides/black-foam-rust.html

Note the big 24 pin chip in the center of the photo and the two 14 pin
DIPs to its left. Those were gold plated IC leads. So much for
corrosion proofing.

you need to use some silica gel packs to remove the moisture from the
containers.

Sure, but it's a bit late for these chips. I think they were in the
closet for at least 15 years. Any desiccant would have been saturated
with water after a few years unless sealed everything in an airtight
container. I could need to renew the silica gel by baking off the
moisture, but that would require I setup a proper maintenance
schedule. These daze, I just use storage tubes and use the black foam
only for short term storage.

Also, I use rice for desiccant in pill bottles, salt shakers, and
hygroscopic component containers. Not great, but good enough.



--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS

Jeff Liebermann wrote:
Also, I use rice for desiccant in pill bottles, salt shakers, and
hygroscopic component containers. Not great, but good enough.

To ratchet up the paradigm,
Minute Rice works better than the never-been-cooked rice.

On Wed, 30 Sep 2009 16:35:18 +1000, Bob Larter
wrote:

Well, it hasn't happened to me yet, but then the parts I have in foam
have only been there for a maximum of about 3 years.

3 years and a dry storage area is not going to cause problems. Add a
roof leak in my storage closet, and it probably won't last a few
months.

I wonder if it's a
general problem, or whether it's only a problem for particular brands of
foam?

The crumbling to dust problem certainly varies with type and
manufactory. I have some that are at least 30 years old and are in
perfect condition. Others have crumbled to dust. As near as I can
tell, the stuff that is fairly brittle and breaks when you bend it has
survived. The stuff that is fairly flexible, and bends easily, has
crumbled.

As for moisture abosorption, I'll guess(tm) that there some kind of
chemical reaction between the graphite impregnated foam and the
condensed water. It must be something rather strong because, as is
evident in my photo at:
http://www.11junk.com/pics/drivel/slides/black-foam-rust.html
it even corroded gold plated IC leads. I have a difficult time
imagining foam and water creating any acid that strong, but it's
possible.



--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com
# http://www.LearnByDestroying.com AE6KS

On Oct 1, 10:45*pm, Jeff Liebermann wrote:
On Wed, 30 Sep 2009 16:35:18 +1000, Bob Larter
wrote:

Well, it hasn't happened to me yet, but then the parts I have in foam
have only been there for a maximum of about 3 years.

3 years and a dry storage area is not going to cause problems. *Add a
roof leak in my storage closet, and it probably won't last a few
months.

I wonder if it's a
general problem, or whether it's only a problem for particular brands of
foam?

The crumbling to dust problem certainly varies with type and
manufactory. *I have some that are at least 30 years old and are in
perfect condition. *Others have crumbled to dust. *As near as I can
tell, the stuff that is fairly brittle and breaks when you bend it has
survived. *The stuff that is fairly flexible, and bends easily, has
crumbled.

As for moisture abosorption, I'll guess(tm) that there some kind of
chemical reaction between the graphite impregnated foam and the
condensed water. *It must be something rather strong because, as is
evident in my photo at:
http://www.11junk.com/pics/drivel/slides/black-foam-rust.html
it even corroded gold plated IC leads. *I have a difficult time
imagining foam and water creating any acid that strong, but it's
possible.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
#http://802.11junk.com* * * * * * *
#http://www.LearnByDestroying.com* * * * * * * AE6KS

Perhaps the corrosion is from the left over flux salts attacking the
metal in the presence of moisture?
al

On Sat, 3 Oct 2009 05:57:53 -0700 (PDT), mickgeyver
wrote:

Perhaps the corrosion is from the left over flux salts attacking the
metal in the presence of moisture?
al

http://www.11junk.com/pics/drivel/slides/black-foam-rust.html
Good theory, but probably not. All of the IC's on the tray in my
photo are new and have never been soldered. I also use non-corrosive
rosin flux and am fairly good about cleaning off any flux with solvent
after soldering (and de-soldering). My photo is from one of the trays
of IC's that remained after I tossed about 5 other black foam pads
full of rotted IC's. Every IC had severely corroded leads. Bend the
lead and it just breaks. Except for the gold plated leads, the other
IC's were only damaged where they contacted the black foam.

It's not easy to see on my photo, but when I pull out an IC from the
foam, some of the foam comes with the leads. It's not unusual to pull
out a small chunk of foam with the IC. I'm not sure of the
significance, but it does indicate that whatever chemical reaction was
involved also causes the foam to harden.

I'm still mystified what would attack gold plated lead.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558