Hans,
I to have a vintage Hollis machine, GBS Mark II, that we run an oil blanket on. We clean
the sludge off the pot once a week using a slotted spoon. The sludge is sold with our
solder scrap for reclaiming.
Every day when the solder pumps are shut off, new old is added to the side of the pot
furthest from the overflow pipe. This is done to flush all to old oil off the pot.
I would only replace the solder based on the results of a solder analysis. If it is
showing that it is contaminated, I would drop half the pot and refill. Why half , you may
ask. Based on years of watching the contamination levels in our pot I observed the
following. After dropping the whole pot I would see the contamination levels climb quickly
for the first 2-3 months and then it would level out and start approaching the
contamination limits at an exponential rate. The exponential part can go on for months
and months, depending on how much solder you drag out of the machine when soldering.
By replacing only half, I don't suffer the quick rise in contamination, I save myself
about 425 lbs of solder, and I recharge the system quicker because I have hot solder to
melt the new into, rather than pulsing the heater till the solder melts (them immersion
heaters can really get glowing when they don't have solder melted around them to draw the
heat out).
Gary Camac
Hinners Hans Civ WRALC/LYPME wrote:
> Hi Everybody,
>
> I've been asked to troubleshoot a BIG problem with our wave flow soldering
> machine and I could use some advice. I'm in the beginning stages of
> learning about wave flow soldering.
>
> We use Tin Lead 63/37 solder with Kester-5738 Dross Inhibiting Oil and, to
> date, my solder analysis has come back fine.
> And recently, we've been getting alot of bridging on assemblies (multilayer
> FR-4). No surprise really, there is an embarrassing amount of scum
> (dross-?) and our Tinning oil is gunking up. We've only used this oil for a
> few months so it's the only reported process change. The joints look It's
> an old Hollis machine (bought in '83) that has seen better days. The first
> thing management said was, "Should we go and buy a new machine?" Showed
> Kester the pics and they said the oil was at the end of its life and broke
> down.
>
> I threw a couple of pictures on my public drive starting with the word
> 'Solder -'. I kept them fairly large (~500 k each) so people can get a good
> idea of what I'm up against. For the digital buffs, they're scaled down 60%
> from the originals using a Sony DSC-D700 camera.
>
> http://www.driveway.com/share?sid=a8f3cb1d.96df8&name=Pictures
>
> Thoughts, questions, suggestions, . . . . prayers?
>
> Do we just need to scoop the gunk out (that was my weekend) and keep going?
> Start over with a fresh bath of solder?
>
> The more I do, the more I learn . . . the hard way.
>
> Hans
>
> ~~~~~~~~~~~~~~~~~~~
> Hans M. Hinners
> Materials Engineer (Process & Manufacturing)
> Warner Robins Air Logistics Center
> Avionics Production Division
> Manufacturing Branch
> 380 Second Street, Suite 104
> Building: 640, Mail Stop: LYPME
> Robins AFB, GA 31098-1638
> Voice: (478) 926 - 1970 Fax: (478) 926 - 7164
> mailto:[log in to unmask]
> http://www.robins.af.mil
>
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