I've just looked up the assay of our main lead free bath and on average
it has been tested on a bi-monthly basis since 2007 which was the last
time we changed the alloy.
Dross recovery has been used during that period and I cannot attribute
any change to the bath in that period to the recovery process.
I cannot recall ever having to put in any correction alloy either!
Regards
Rex


Rex Waygood
Technical Manager

Hansatech EMS provides value manufacturing through engineering and
quality

Hansatech EMS Limited
Benson Road
Nuffield Industrial Estate
Poole
Dorset BH17 0RY
United Kingdom
[log in to unmask]
www.HansatechEMS.com 



-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Nutting
Sent: 17 September 2012 14:56
To: [log in to unmask]
Subject: Re: [TN] Recycled solder?

Mike,

In all my reading of notes here on Technet and in the trade mags and web
sites we are supposed to monitor our solder pots for levels of copper,
gold etc. that are "stripped off" the boards as they are soldered.  If
we simply squeeze out the "good" solder from the dross aren't we also
getting the higher levels of contaminants that would have been in the
solder pots?  So, do we really consider this recycled solder as pure as
the new stuff that comes from the likes of Metallic Resources, Kester,
Alpha Metals, et al.?

Phil Nutting

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Mike Fenner
Sent: Friday, September 14, 2012 4:23 PM
To: [log in to unmask]
Subject: Re: [TN] Recycled solder?

Oh, I think it's stretching a bit to call it recycling, but it was nice
of them to tell you.
Most people over-skim their pots and "dross" usually contains a
significant amount of good metal. There are a number of mechanical
devices which rely on this and work by squeezing out the metal to get it
back.
A little while back someone or other promoted a new chemical additive
for aiding this process. Bemusingly, at least for me, there was quite a
lot fuss about this as I remember, including on this forum. I think one
supplier even got an award for it. Actually none of this is new - just
another example of recycling. These products/techniques were common from
the earliest days of wave soldering.
Footnote.
Ironically, the money/credit they get for their dross will go down
dramatically, as it really will be dross. [Assuming their
recycler/supplier has been playing an honest game with them.]



Regards


Mike


-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Pete
Sent: Friday, September 14, 2012 2:56 PM
To: [log in to unmask]
Subject: Re: [TN] Recycled solder?

My understanding is that they will do the recycling themselves, on site.
They said the recycling would be mechanical, not chemical, so maybe it
is just squeezing out the droww.  They also said it was an effort to be
environmentally conscious, but they are in China, so I'd think it's
really cost.

We are among their smaller customers, so I can't make a lot of demands.
They asked if we would accept boards made with recycled solder.  I
suppose the best I can do is reply with a list of concerns and ask for
test results.

Thanks!

Pete



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