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Subject: Re: [Homebrew_PCBs] Solder paste advice

From: "Stuart Schaffert" <stuart@...>
Date: 2008-04-23

I have a customer that uses our temperature monitoring equipment to make sure their solder paste never gets colder that 37 degrees or warmer than 45 degrees fahrenheit during storage.

Stuart


----- Original Message -----
From: Dylan Smith
To: Homebrew_PCBs@yahoogroups.com
Sent: Wednesday, April 23, 2008 2:15 PM
Subject: [Homebrew_PCBs] Solder paste advice


Hi list,

For the first time today I used solder paste. Much nicer way of soldering
fine pitch SMD - using the soldering iron to do it was getting old rather
fast. My method was to lay down a bead of paste on each row of pads, place
the chip, then use a hot air gun. It was nice not to have to spend 15
minutes carefully lining up a big LQFP then bodging it when trying to tack
the first pin and starting again. I had read that the component will try
and centre itself thanks to surface tension, and this turned out to be a
good tip.

My main problem at the moment is putting down to much paste rather than
too little... but I had far less solder to wick up after soldering than
doing it by hand and the result is much neater.

The paste I got is Edsyn CR44 - it seemed reasonably easy to apply. I
bought a syringe of the stuff.

What's the best way of making the solder paste keep for as long as
possible? I had heard that it had to be kept refrigerated, and that it
would only be sent same day frieght and all this sort of thing but as far
as I could tell, Farnell didn't treat the order any differently than any
other component (it certainly didn't go with any priority - took 2 days to
get to me!)





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