Hi Phil! I am guessing then that your components are Sn95/Pb5 in alloy
composition - if you use an aggressive flux (such as an H per JSTD-004) and
pretin the components prior to using them in assembly I would suspect that
you would have success. If the copper has migrated to the surface of the
wire finish then you will have oxidized copper/tin IMC which will be a bear
to pretin but can be accomplished.  I recommend you also have confidence
that your pretinning cleaning process eliminates any "bad" residues prior
to the components going to assembly. Good Luck.

Dave



                      Phil Nutting
                      <PNutting@KAISERS        To:       [log in to unmask]
                      YSTEMS.COM>              cc:
                      Sent by: TechNet         Subject:  Re: [TN] cleaning oxidized THT component leads
                      <[log in to unmask]>


                      02/26/2003 12:14
                      PM
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                      Forum."; Please
                      respond to Phil
                      Nutting






Dave,

From the manufacturer's spec sheet;
Leads... Tinned solid copper wire (medium lead content 5%)

I'm going to do some tests on solderability, both by hand and in the wave
to get a handle on production and repair solutions.

Phil

-----Original Message-----
From: Dave Hillman [mailto:[log in to unmask]]
Sent: Wednesday, February 26, 2003 11:03 AM
To: [log in to unmask]
Subject: Re: [TN] cleaning oxidized THT component leads


Hi Phil! I would echo Brian's comments about using an abrasive/mechanical
oxide removal procedure - too great of an opportunity to create
nonwetting/dewetting situations. There are a number of other chemical oxide
removal procedures (e.g. SolderNu, aggressive fluxes, acid treatments) but
realize that any chemical treatment has the potential for causing a
contamination issue of the component itself which could later be a latent
defect. What is the component finish composition - Sn63?

Dave Hillman
Rockwell Collins
[log in to unmask]




                      Phil Nutting
                      <PNutting@KAISERS        To:       [log in to unmask]
                      YSTEMS.COM>              cc:
                      Sent by: TechNet         Subject:  [TN] cleaning
                      oxidized THT component leads
                      <[log in to unmask]>


                      02/24/2003 10:58
                      AM
                      Please respond to
                      "TechNet E-Mail
                      Forum."; Please
                      respond to Phil
                      Nutting






I have some THT capacitors that seem to have an oxide layer preventing good
solder joints.  The parts were purchased about 5 years ago and are stored
loose in the stockroom bin.  Aside for changing our storage habits and
polishing each lead with Scotchbrite before soldering, is there a better,
faster or easier way of cleaning the leads before soldering?

Thanks in advance for your collective wisdom.

Phil Nutting

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