[sdiy] The case of the sticky solder pt. 2

[Scott Gravenhorst]

Try a test on a piece of board that can be discarded - use steel wool or emery paper
or even fine grade sand paper to burnish the copper first.  Then try to solder to
it.  If this works, then something has either tarnished or deposited (some oily
based material) on the boards you are having problems with.  Not getting the piece
hot enough may also be a problem.  If copper is clean and hot enough, the solder
should flow on it.  A certain amount of tip-to-work pressure is required to transfer
enough heat energy from the iron to the work to get the work hot enough so make sure
you are pressing down on the board with the iron.

I've never had "bad" solder.  If it flows on the iron - it's melting point is good
so it should flow on the copper - if the copper is clean and sufficiently hot.


Sam Ecoff <secoff at execpc.com> wrote:
>So, I did a little soldering tonight, this time at the correct  
>temperature (700 degrees F). I had previous set the iron to only 350,  
>so things went considerably better tonight. However, the solder is  
>still misbehaving. It's still more interested to stick to the iron's  
>tip than to components and pads on the board.
>
>Ken Stone suggested in a private e-mail that the pads may have become  
>dirty or oxidized, but I can't see how that could have happened as I  
>keep the boards wrapped in anti-static plastic when I'm not working  
>on them in a temperature and humidity controlled environment (68  
>degrees F, 30-35% relative humidity). I wash them each time I finish  
>soldering a few more components and use a gentle nylon brush which  
>means that each board is getting scrubbed 5-6 times, which I would  
>guess is enough to remove oil left by my hands. I've had these boards  
>in my possession for maybe 3 months, and none of them are copper  
>boards. All stuff from Tom Gamble, Ray Wilson, and Ken Stone. Have I  
>missed something here which could have caused the boards to get dirty  
>or oxidized? I suppose I could wear latex gloves to keep oil from my  
>hands completely off the pads, but that seems a tad anal. I just  
>can't figure how they would get dirty otherwise.
>
>While I appreciate the tips on soldering technique, I know that I  
>haven't changed what I'm doing, but the result has changed. I used to  
>be able to go down a row of pins on an IC socket zip-zip-zip, and now  
>it's 10+ minutes of work to get the solder to stay on the pads.
>
>I just upgraded my Rat Shack iron to an entry level weller, which has  
>helped the problem a bit, but the solder is still more interested to  
>stick to the iron's tip than to pads and component legs. The only  
>other thing that I can think that has changed since I began my  
>current projects is that I used up the batch of Kester 331 that I had  
>originally purchased from John Blacet while building his excellent  
>kits, and I am now using a reel of 331 I purchased from Mouser. So  
>here's a question... does solder go bad? Has anyone ever gotten a bad  
>reel? I'm just left scratching my head here, because I'm eliminating  
>variables but haven't seen much improvement yet. I guess the next  
>step will be to try some of the Kester 245 I bought and see if things  
>are different. I'm planning to solder up a few pots tomorrow night,  
>so I'll use the 245 and then report back. If anyone has any ideas as  
>to what the hell is going wrong (or what I'm doing wrong) please feel  
>free to chime in.
>
>As always, I'm grateful for all of the help and suggestions I've  
>received.
>
>Kind regards,
>
>Sam E.
>_______________________________
>Sam Ecoff
>Secret Society Productions
>5307 S. 92nd St. Suite 105
>Hales Corners, WI 53130
>(414) 427-0615
>www.samecoff.com
>
>

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-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
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