Drag soldering

A big tip o’ the hat to Chris N2YYZ for passing along a new-to-me technique for soldering tiny SMD parts.

I’ve heard of the hot air flow method and the heat-it-in-a-skillet method with solder paste as well as a few other techniques but drag soldering? That’s a new one on me and I must say, it looks impressive.

I’ve never heard this method mentioned in all the reading of various groups over the years so maybe it’ll be new to others as well.

As Chris says, the flux does all the work for you as far as keeping the solder contained to where it’s needed. I wish I’d known about it prior to those tiny chips I just finished soldering old school but now, sure as the sun comes up in the east, I’m going to be shopping for a new kit just to implement this method. Thanks Chris – just what I needed!

There are several videos on YouTube and elsewhere of soldering SMD chips with solder paste by squirting the paste across the pins of the chip – I know it works but it seems counterintuitive to me to purposely spread conductive solder across pins. I don’t think I could bring myself to do it.

But gel flux? Seems safer and accomplishes the same thing via a different method, even though the physics is the same in how the solder bonds to where it’s needed and is wicked away from where it’s not.

Enough talking – check out the video, courtesy of Howard Electronic Instruments:

.

.

  3 comments for “Drag soldering

  1. Chris N2YYZ
    March 26, 2012 at 9:25 pm

    Glad to pass this along to you, John, and really quite flattered to see this tip result in a full-fledged blog post!

    Here’s a few more good resources on SMD soldering.

    Sparkfun, a hobbyist electronics site that serves the “maker” community, has a good series of tutorials on SMD soldering:

    http://www.sparkfun.com/tutorials/category/2

    If you have a bit more time, there’s a really good 40 minute video published by Dave of EEVblog, all about SMD and SMD soldering:

    http://www.youtube.com/watch?v=b9FC9fAlfQE

    Well worth a look.

    vy 73! de Chris N2YYZ

    • March 27, 2012 at 5:50 am

      Chris, I’ve never heard of this technique mentioned even among SMD kit-builders on the ATS YahooGroup and similar. Maybe it will remove a bit of the hesitation some have regarding these types of kits. I wish I’d known about it 2 weeks ago!

      Thanks for the additional links.

  2. March 27, 2012 at 1:15 pm

    A query to QRP-L on non-ATS kits using SMD chips yielded the following:
    http://www.qsl.net/k5bcq/Kits/Kits.html

    http://www.radio-kits.co.uk/hunter/index.htm

Leave a Reply

Your email address will not be published.