Lesee... The design of clocks, especially mechanical watches, has always fascinated me. I built a 24-inch long model of the USS Constitution once with about half a jillion tiny knots in the rigging, all done by hand using tweezers.
With that background, I simply found the advent of SMC's "interesting". I already had an optivisor. My first experience was with removing and replacing them on pc boards with no specialized tools while repairing "land mobile" radios in the 80's. Later it was doing the same thing sitting cross-legged on a cold steel floor using a "porta-sol" butane iron and a small flashlight clamped in my teeth while servicing electronics on ships. At least in the land mobile shop I had a soldering station, comfortable bench and good light, but the shipboard experience proved that with enough practice one can get good results in very primitive conditions. Patience, good vision aids (if you're old enough that you can't focus on the tip of your nose any longer), a solder sucker or braid and sharp knife, and a pair of tweezers are the basics, in my experience. Oh, and a pair of soft-soled shoes helps. If you pick up a "pebble" on your shoe, you can be sure it's a resistor or a capacitor. Removing 'em, I use braid or a sucker to take all the solder off I can. Usually the part is still stuck by a tiny thin film of solder at each terminal bonding it to the board. A razor blade or very sharp hobby knife run along that seam will separate the part from the board without damaging either. Be sure to hold the part down with a small screwdriver or one blade of the tweezers when you remove the last bit of solder or you may have to pick it off of the bottom of your shoe eventually. Putting an SMC on, I hold the part in place with the tip of the tweezers, then "tack solder" one end using just the iron with a tiny amount of solder on it. Then I let go of the tweezers and properly solder the other end before going back to the first tack solder spot and finishing it, if needed. If the pad/part are tinned properly, just touching it with the iron the first time often solders it FB. You don't need a lot of solder. Make sure any solder on the pc-board pads is VERY thin. You don't want the part held off the board on islands of solder or stressing a terminal by pushing down on it after one end is soldered with the part not lying flat on the board. When replacing parts, I often use a bit of solder braid heated by the iron to "dry" the board pads as much as possible before installing the new part. Multi-pin transistors and I.C.s work just the same, but with more terminals. There are specialized irons that will heat both terminals on an SMC cap or resistor simultaneously, or even a whole I.C. If I were to do a lot of SMC work on my bench, I'd probably get one. Like any soldering, taking parts off cleanly is more work than putting 'em on. Frankly, most SMC's are too cheap to worry about much, unless I want to check the part out-of-circuit after it's off. So I worry about the board and I'm quick to sacrifice the part during removal if that makes things easier. In that regard, it's no different than replacing through-hole parts. Prefer Grandfather clocks to watches? Then at least through-hole and possibly vacuum tube stuff is likely a much more interesting project <G>. Ron AC7AC -----Original Message----- ...How hard is SMT soldering, really? I've been lusting after the TAPR Software Defined Radio kit,(http://www.tapr.org/tapr/html/Fdsp10.html) but it's majority SMT. I'm in my 30's, with fairly steady hands and decent vision... with the proper tools, should I be able to do this? Any experienced SMT builders out there got any pointers? Please respond to me directly - I'll summarize for the list later if there's interest. Now, for the other shoe - I just ordered a KX1 to go with my now almost 5 year old K2 (#668). This should be fun! 73 DE KF4BAL/V73 Richard Perry _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
