AVR-Chat

----- Original Message ----- 
From: "arhodes19044" <spamiam@comcast.net>
To: <AVR-Chat@yahoogroups.com>
Sent: Tuesday, June 14, 2005 1:28 PM
Subject: [AVR-Chat] Re: Any ideas on socket for ATmega128/64 ? - Drag 
soldering


> --- In AVR-Chat@yahoogroups.com, Don Ingram <don@l...> wrote:
>> It amazed me when I started as to how your muscles etc 'servo' to
> what
>> your eyes can see. if you have the magnification for the eyes, the
> hands
>> can do some extremely fine work. On protos I often ended up
> soldering
>> bits of kynar wire onto fine legs of IC,s to add a quick logic
> analyser
>> test socket or the like.
>
>
> yes, I have done some extremely fine work with sufficient
> magnification.  The finest work I ever did was dissecting one layer
> of nerve cells from another in a retina.  I forget what
> magnification it was, but it was quite tedious.
>
> I also found that fine motor tremor was noticeably worse if I had
> even one beer the night before.  Since I did that work on weekends
> (in college), it put a crimp in my partying.
>
> The loupes I currently use have much less magnification, but with my
> crude soldering iron.....  it has more than enough mag.
>
> I was considering getting a 1/64" tip for an iron, but now I think
> that something slightly wider (chisel tip shape) may be better
> for "drag soldering".
>
> I still have not found a good reference on the technique of drag
> soldering?  I t seems as if the technique is to make a blob of
> solder and drag it across all the pads on one side of the chip.  I
> guess the solder mask prevents bridging?  I would have thought that
> all the pins would just get shorted together in one big glom of
> solder....

The trick is to use plenty of liquid flux. It helps if you have a special 
tip like Metcal's 'mini-hoof' which is made specifically for drag soldering:

http://www.metcal.com/tips/minhoof2.html#fine

Leon 


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