Chuck Harris wrote:
Hi Mike,

The process of defluxing involved dipping or spraying the chassis
in carbon tetrachloride, or later trichlorethylene.

...and you don't want to fool with either with what we know these days.
Tricloroethylene is a carcinogen and is banned in many microelectronic
houses.

--
Brian Denley
http://home.comcast.net/~b.denley/index.html

Brian Denley wrote:
Chuck Harris wrote:

Hi Mike,


The process of defluxing involved dipping or spraying the chassis
in carbon tetrachloride, or later trichlorethylene.


..and you don't want to fool with either with what we know these days.
Tricloroethylene is a carcinogen and is banned in many microelectronic
houses.


So is gasoline, but there you are pumping it into
your car every week... sniffing the fumes that waift
up to your nose, wiping the spillage from the leaky
nozzles off of your hands.

I was involved in industry back in the hay day of
trichloroethylene. It was used in careless and ridiculous
ways. We had open jugs of the stuff everywhere.
We used it in vapor degreasers to remove solder flux,
photoresist, just about anything. There was nothing
in use before, or since that works as well as it
does.

Perhaps it is a carcinogen, perhaps it isn't. In any case,
banning it was a "knee jerk" over reaction. It would have
been better to encourage safer ways of using the solvent.

Instead, we have spent the last 30 years playing cat-and-mouse
games with the needs of industry for a good general purpose
solvent, and the needs of the regulatory agencies to ban
anything that has even a remote chance of being harmful.

Carbon tet was the king, it got dethroned, so they replaced one
of the chlorines with an ethylene molecule, and trichlor came
about. It was banned, so they changed the ethylene to an ethane,
and then a butylene, and then a butane, and then ... The latest
in the chain is pentachloroethylene. It will be banned one of
these days too. It won't take off solder flux, or much of anything
else.

As far as I can tell from my casual research on the subject, not
one single human has ever contracted a case of liver cancer
proven to be caused by exposure to trichloroethylene. Plenty
of rats have, but the amounts they were exposed to, or ingested
would never happen in real life.... well, not unless you were
trying to commit suicide with the stuff.

-Chuck Harris

Water soluable means the flux will absorb moisture from the air. On very
dry days everything will be fine, but leave the item in a humid evvironment
for a few days and just about every circuit will malfunction.

BTW, if you have a power supply with maybe 48 volts inside and a humid
environment, the flux will eventually cause a carbon track to form on the PC
board, and eventually it will arc over. Try it! It is repeatable, and will
cause a nice fire.

CLEAN OFF THIS FLUX!!


"Mike Knudsen" wrote in message
...
I just received the following from a friend who has been building
electronic
circuits for his home pipe organ (talk about boat anchors). He got shorts
in a
solid state circuit, so imagine what the new solder he describes would do
in
high-impedance tube gear!

Apparently some solder makers are using a new "organic" flux that cleans
off PC
boards easier, but is conductive. I quote:

At the point that I had completed 5 of these, I ran out of my usual spool
of
Kester solder and began using another (spool of Kester solder). I recall
that
the odor of the melting flux was strange and different than that of the
older
spool.

Now I discover that the flux residue on the new spool is CONDUCTIVE! It's
easy
to discern the difference between the old and the new: the earlier
"rosin"
material was yellowish and hard, and when you picked at the edges of it,
it
would break off in hard granules. The new residue is clear and soft,
about the
consistency of ear wax. (The label on the spool says that the flux is
"Organic," so perhaps it *is* ear wax.)
(end quote)
--Mike K.

Oscar loves trash, but hates Spam! Delete him to reply to me.

Chuck:
I, like you, worked back in those days with trich. I accidentally
'degreased' my hands more times than I care to remember. Boy, did that
sting! I do have a skin condition on my hands now and , while I don't know
what really caused it, it makes me wonder. We had great success also with
1544 flux and Freon TMS degreasers but we can't use those anymore because of
the ozone problem.

--
Brian Denley
http://home.comcast.net/~b.denley/index.html

Hi Brian,

I am probably going to go back to the Kester 331 water soluble flux
solder. I hate the stuff. It burns my nose, eats the tips off of my
irons, and just plain smells awful! But, it makes a pretty joint, works
nicely even on ugly looking wires, and washes off with nothing more than
a dip in warm sudsy water.

Isopropyl alcohol works, but only if you soak for 5 minutes, and then
scrub with a tooth brush. You have to clean with your first solution to
remove the solder flake, and most of the flux, then you have to dry and
rinse with fresh alcohol to remove any left over flux that went into
solution. One of these days, I am going to catch the place on fire.

-Chuck Harris

Brian Denley wrote:
Chuck:
I, like you, worked back in those days with trich. I accidentally
'degreased' my hands more times than I care to remember. Boy, did that
sting! I do have a skin condition on my hands now and , while I don't know
what really caused it, it makes me wonder. We had great success also with
1544 flux and Freon TMS degreasers but we can't use those anymore because of
the ozone problem.

"Chuck Harris" wrote in message
...
Brian Denley wrote:
Chuck Harris wrote:

Hi Mike,


The process of defluxing involved dipping or spraying the chassis
in carbon tetrachloride, or later trichlorethylene.


..and you don't want to fool with either with what we know these days.
Tricloroethylene is a carcinogen and is banned in many microelectronic
houses.


So is gasoline, but there you are pumping it into
your car every week... sniffing the fumes that waift
up to your nose, wiping the spillage from the leaky
nozzles off of your hands.

I was involved in industry back in the hay day of
trichloroethylene. It was used in careless and ridiculous
ways. We had open jugs of the stuff everywhere.
We used it in vapor degreasers to remove solder flux,
photoresist, just about anything. There was nothing
in use before, or since that works as well as it
does.

Perhaps it is a carcinogen, perhaps it isn't. In any case,
banning it was a "knee jerk" over reaction. It would have
been better to encourage safer ways of using the solvent.

Instead, we have spent the last 30 years playing cat-and-mouse
games with the needs of industry for a good general purpose
solvent, and the needs of the regulatory agencies to ban
anything that has even a remote chance of being harmful.

Carbon tet was the king, it got dethroned, so they replaced one
of the chlorines with an ethylene molecule, and trichlor came
about. It was banned, so they changed the ethylene to an ethane,
and then a butylene, and then a butane, and then ... The latest
in the chain is pentachloroethylene. It will be banned one of
these days too. It won't take off solder flux, or much of anything
else.

As far as I can tell from my casual research on the subject, not
one single human has ever contracted a case of liver cancer
proven to be caused by exposure to trichloroethylene. Plenty
of rats have, but the amounts they were exposed to, or ingested
would never happen in real life.... well, not unless you were
trying to commit suicide with the stuff.

Something like when they banned sacharin as a sugar substitute. They fed
the rats an equivalent of 500 cups of coffee a day and .01% more rats got
cancer than if they had not been fed sacharin. But the people pushing
the new stuff got the old stuff banned.

-Chuck Harris

Thinker wrote:


Something like when they banned sacharin as a sugar substitute. They fed
the rats an equivalent of 500 cups of coffee a day and .01% more rats got
cancer than if they had not been fed sacharin. But the people pushing
the new stuff got the old stuff banned.

I think you mean cyclamates. Saccharin is still in use, and sold as
"Sweet-N-Low".

Bob Weiss N2IXK

As far as I can tell from my casual research on the subject, not
one single human has ever contracted a case of liver cancer
proven to be caused by exposure to trichloroethylene. Plenty
of rats have, but the amounts they were exposed to, or ingested
would never happen in real life.... well, not unless you were
trying to commit suicide with the stuff.



Up in Woburn Mass there was a company that made production line machinery
for the pharmaceutical industry. They would sometimes take greasy gears out
back and clean them off with trich and dump the residue on the ground. Not
much, maybe 50 gallons over several years. Unfortunately, there was an
underground aquifer that ran there and led to a town well. In the
neighborhood the well fed, there was an extremely high incidence of leukemia
in children. Big time incidence. This was very real and a great tragedy
for many families.

I worked next door (Cummings Industrial Park) and used to watch the hazmat
crews digging the whole place up. We wouldn't drink the town water even
after they said it was cleaned up.

Just because your "casual research" doesn't come up with something doesn't
mean there isn't something there.

Peter

Hi Peter,

Now that is a horse of a different color! In the case of industrial
use, exposure doesn't include ingesting the stuff... unless you are
suicidal, I suppose.

But, in the case of contaminated ground water, the poor residents were
drinking the stuff on a continual basis. The same problem exists where
buried gasoline storage tanks leak into the ground water. Yet, gasoline
the king of carcinoma is in general and rather casual use.

Trichlor is a real problem for ground water. It is about twice as
dense as water, so if it hits the ground, it can travel anywhere water
can, only faster. Trichlor poured onto the ground always ends up in
the ground water.

Banning trichlor because it is a carcinogen in high doses, doesn't make
sense. It is too useful a solvent. Regulating its use and disposal is
what should have been done.

-Chuck Harris


Peter Gottlieb wrote:

Up in Woburn Mass there was a company that made production line machinery
for the pharmaceutical industry. They would sometimes take greasy gears out
back and clean them off with trich and dump the residue on the ground. Not
much, maybe 50 gallons over several years. Unfortunately, there was an
underground aquifer that ran there and led to a town well. In the
neighborhood the well fed, there was an extremely high incidence of leukemia
in children. Big time incidence. This was very real and a great tragedy
for many families.

I worked next door (Cummings Industrial Park) and used to watch the hazmat
crews digging the whole place up. We wouldn't drink the town water even
after they said it was cleaned up.

Just because your "casual research" doesn't come up with something doesn't
mean there isn't something there.

Peter

As far as I can tell from my casual research on the subject, not
one single human has ever contracted a case of liver cancer
proven to be caused by exposure to trichloroethylene. Plenty
of rats have, but the amounts they were exposed to, or ingested
would never happen in real life.... well, not unless you were
trying to commit suicide with the stuff.

-Chuck Harris
I know about someone who died, he used to get high on the stuff and
one day fell into a tank of trichloroethylene. 7 foot X 2 foot x 5 foot deep
heated tank with cooling coils. That was 15 years ago.
We used to call it trico and you would not have a drink after working on it
all day
instant drunk!


Great for removing grease and dry straight away.

Lee.