I use a 1.6 mm chisel tip on my Hakko 936 soldering station for 99.9% of my circuit board work including building and modifying the Elecraft K2, KX1, XV transverters, and a variety of mini-modules, homebrewing lots of stuff and repairing commercial gear.
The challenge is to transfer heat efficiently. Whoever wrote the Elecraft doc on soldering was trying to give readers some way to judge whether a given tip is "about right", but don't take 85%-95% of the trace width too seriously. Normally I place the flat side of the 1.6 mm chisel tip right against the joint to be soldered and then add solder. If the pad is extremely tiny, I just use the side of the chisel tip. Solder should flow around the joint in about three seconds if the heat transfer is correct. The danger to the pc board trace is in letting the iron sit on the trace too long. Eventually the heat will debond the trace from the board. That has very little to do with the temperature of the iron (as long as it's hot enough to melt solder) and almost everything to do with the length of time the iron is on the trace. Many folks make the mistake of using too low of an iron temperature, requiring a long "dwell" time on the trace, and are disappointed to see it debond even though the iron temperature was at 700F or below. I normally solder at 750F or 800F. I switch tips (or irons) when soldering to a large surface area of copper, such as the ground plane covering one side of some boards or a coaxial connector. A whole side of a pc board plated with copper or the big fittings on coax connectors will immediately absorb and dissipate the heat. A large tip helps transfer heat quickly, but you should still have an iron capable of delivering the calories of heat needed. For example, my favorite coaxial cable connector soldering iron, especially for soldering the braid to a SO-239 connector, is a Weller 275 watt D-550 soldering gun I've had since about 1955. (All I have to do is wave that big gun near most circuit boards and I'm sure I can see them cringe!) Ron AC7AC -----Original Message----- Hi gang, This document on the Elecraft web site, http://bit.ly/solderingtips says, "[Soldering iron] tip width will normally be in the range of 1/32" (0.79mm) through 1/8" (3.2mm), depending upon the width of the pad to which you are soldering. The width of the tip selected should be about 75% to 90% of the width of the pad." What would you estimate to be the median or modal (or just typical ;-) solder pad width on the K2's circuit boards? Or, to be more direct, which of the following soldering tip widths would be best for use in building a K2: 0.80 mm, 1.19 mm, 1.60 mm, or 2.40 mm? Or am I just splitting hairs? Thanks very much, 73 & 72, Jeff NE2J (formerly WB5GWB) ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
