Hi The first problem in soldering is the iron itself. Although a K2 can be built with a simple soldering iron the problem with most of them is they get too hot to make up for the lack of capacity. These simple irons have elements that must reach a reasonable temperature and hold that temperature. With out any switching or feed back to regulate the iron they tend to be too hot when not being used and too cold when you try to make a joint. A soldering station on the other hand has a high capacity heater and a control circuit or mechanical switch that can sense the tip temperature and apply the correct amount of power to the tip to keep it at the correct temperature. I highly recommend buying a temperature controlled soldering station.
The next mistake is selecting too cold of a tip temperature. This goes against what you would think as you would expect a hot tip would be more likely to damage the board but this not the case, within reason. A 700-750 degree iron will heat the joint quicker and allow you to get on make the joint and get off of the board faster than a 600 degree tip. It is the dwell time on the board that is more important than the temperature when it comes to board damage. The recommended solder is 60/40 rosin core or better yet 63/37 rosin core solder. Multicore or Kester 44 fit these requirements. 0.031 or preferably 0.025 diameter should be used. Silver solder is NOT recommended because it is harder to remove in case of a mistake or rework required to install options. If you have some experience soldering then no-clean flux will make the board look better but it is harder to make good joints with this solder because of the low amount of flux in the core. Of course acid core or water soluble solders should never be used and will void the warranty. As far as technique this takes some experience. Building one or two of the mini kits is a good way to start. Every K2-K1-KX1 owner needs a dummy load so build the DL1 to practice your soldering. Remember to heat the joint not the solder. The joint should be hot enough to melt the solder when the fresh solder is applied. Each joint should take about 2-3 seconds to make and the iron should be removed. If it does not look good allow a few seconds to cool and retouch the iron for 1 or 2 seconds to reflow the joint do not add more solder. One of the other problems is too much solder. Using 0.025 diameter solder will help here. The pads are plated through so it is not necessary to fill the hole so it comes through to the other side. Just a smooth fillet on the bottom of the board is all that is needed. The solder should not be mounded up into a ball on the pad. The something else is tinning toroid leads. This is still the number one problem. The wire needs to be tinned all the way up to the core so when the wire is pulled tight you are not pulling the insulation down into the pad. There are many ways to strip and tin the wires. Just make sure you do a good job here and you will avoid many problems. Don Brown KD5NDB ----- Original Message ----- From: "Craig Rairdin" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Tuesday, February 28, 2006 10:36 AM Subject: [Elecraft] Poor soldering (was: Does build quality affectperformance?) > However, since the biggest problem that beginners seem to have is > poor soldering, sometimes a beginner's rig may have poor joints > that don't cause problems immediately. With that in mind, what are the most common soldering problems? Could we head off errors by discussing them here or beefing up the material on the Elecraft Web site on this topic? Is it: * Iron too hot/cold * Wrong tip * Too much heat applied (damaging part or pad) * Bad technique * Wrong solder * Too much/little solder Or something else? Depending on what the symptoms of the problems are, this would also help new owners choose a builder and help purchasers of used units inspect the work before buying. When I decided to build a K1 I spent a lot of time reading the material on the Elecraft Web site, then I bought a suitable solder station rather than resurrect my old Radio Shack iron. Both my K1 & K2 turned out great with no problems in checkout, alignment, or everyday operation, but you have me worried that I might have screwed up in ways I haven't discovered yet. :-) Craig NZ0R K1 #1966 K2/100 #4941 _______________________________________________ Elecraft mailing list Post to: [email protected] 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
