A Learning Adventure in the Workshop

Surface Mount Device (SMD) Soldering

The Nixie clock project is requiring me to learn a new skill - Surface Mount Device (SMD) soldering.

An SMD is a small electronic component with many small pins down to 0.5mm that need to be individually attached to contact pads on the surface of a printed circuit board.   The pads are very close together, and you must be very careful to not cause solder "bridges" between the pads.

For a machine, this installation is an easy job.  For a human it is more difficult...and for me it is VERY difficult.  But that's why this blog is called "A Learning Adventure."  Soldering SMDs is my "adventure" for the Nixie project.

The following two web sites have SMD hand-soldering tutorials.  Several different methods exist for soldering SMDs, and I will try a couple of them on this project.

This website has three different methods:

http://www.infidigm.net/articles/solder/

This website shows the "flood and suck" method that Peter recommends for the Nixie kit:

http://warmcat.com/milksop/soldering.html

The Nixie kit has two driver chips that require SMD soldering, and I successfully used the "flood and suck" method to install the first one, but I permanently damaged the second driver chip using this method. I learned that you NEVER use a sharp, pointed instrument to scrape out a solder bridge...you will destroy the chip (or at least "I" will).  Always use the copper braid removal method instead.

So, I've ordered a replacement driver chip from Peter Jensen, and when it arrives I will try again.

Nixie Tube Clock Project

The latest issue of Make Magazine featured another Nixie Tube clock maker maker and his kits.  His name is Peter Jensen and he operates www.tubeclock.com. 

A good definition of a Nixie tube is found on Wikipedia (click here).   According to Wikipedia:

"The Nixie display was developed by a small vacuum tube manufacturer called Haydu Brothers Laboratories, and introduced in 1954 by Burroughs Corporation, who purchased Haydu and owned the name Nixie as a trademark. Similar devices that functioned in the same way were patented in the 1920s, and the first mass-produced display tubes were introduced in the late 1930s by National Union Co. and Telefunken. However, their construction was cruder, and they failed to find many applications until digital electronics reached a suitable level of development in the 1950s."

"Nixie tubes were superseded in the 1970s by light-emitting diodes (LEDs), often in the form of seven-segment displays. LEDs are better suited to the low voltages that integrated circuits used, and are much smaller and sturdier without needing a sealed glass tube. Nixie tubes now only exist as a novelty for electronics hobbyists."

Regardless of their history or practicality, they look really cool, and I couldn't resist building one of Peter's clock kits for my office. 

I ordered one from Peter, and the kit is of excellent quality with well labeled parts and great instructions.   I began the kit a couple of night ago and will report again as I make progress.  Peter's kits use new (but old-stock from the space race era) Russian made Nixie tubes, and they definitely have that cold-war aura about them.

Changes!

Once again, its been a while since I have posted.

A lot has changed recently, not the least of which is that I have changed jobs.  I am now the Executive Director of a new research center called CenSCIR at Carnegie Mellon University.  This has been a great change for me, and I am really enjoying the University atmosphere and the increased exposure to fellow tinkerers.  Although, I have to admit that they are all at a significantly higher level of "tinkering" than I am!   Enough about that, this blog is not about work!

The new job has kept me out of the workshop a bit more than usual (plus it has been to sunny in Pittsburgh to spend time inside), but I'm getting the itch to get back to my projects.

I did spend some time trying to cut the decorative ebony plugs for the Greene & Greene desks.  I am trying to use a method that was explained in a recent issue of Fine Woodworking Magazine.  This method allows you drill traditional round holes into the mahogany and then insert square ebony pegs with short round dowels attached to the backs into the round holes.  Thereby reducing some of the gaps that may show in a traditional "mortised"peg hole (at least when done by an amateur like me).

On paper, this method looks good, but I am breaking about 50% of the ebony pegs during the final steps of making them, and this is just too much breakage (I need to make about 28 of these plugs).  I need to work on this method a bit more.