Michael,
thanks for your reply and here are the answers, best I know:
1. What is the capacity of the solderpot?
This solder pot holds about 12 lbs.
2. What is the flux being used?
Almost exclusive to Kester 186-25, but a few drops of a kester OA might be
used in extreme circumstances. The exceptional use of OA is so infrequent
that I would rule it out all together, being used maybe once or twice every six
months.
3. What is the material the pot is made of?
I am almost completely sure that this is milled out of stainless, but the photo
copied manual that I have for this doesn't specify. It does not appear to be
magnetic.
4. Does the problem show up on a new pot charge or does it require time
to develop if so how long?
I have this problem today and it has been two weeks since I changed the
solder. We had a HUGE batch (for us) of parts go through this this week,
about six hundred soic's. These particular components were lead free and we
were having a difficult time getting them to reflow in the smt process without
pre tinning them.
5. What is your definition of "polarized metal stuff"? Are you saying
magnetic or are we getting into dipole moments and ligand field theory?
Well, often when we see this fine hairlike strand, we have to heat the lead and
scrape it off with an iron. It doesn't become molten in normal soldering
temperatures and it doesn't want to let go of the lead that it is attached to. If
we use braid, we often find ourselves chasing it up and down the lead.
Sometimes it seems to attracted to the soldering iron tip, as if magnetic and
somtimes not. We use metcal tips.
I changed this solder pot today and used a new lot/date code of solder. So, I
expect that this problem will appear to go away and I will assume that I have
solved the problem. Then, sometime in the future, I will rear it's ugly head
again. We had this problem in our Corfin tinning system and we blamed the
solder for several months. Finally, they removed the solder pot and replaced it
with a brand new lot of solder and the problem went away. The lot date
codes of solder that I am using have nothing to do with that story, but I
wonder if in the past, this pot could have been contaminated and there are
gremlins floating around in there that only show up on occasion???
Jack Evans,
Aeroflex Colorado
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