Bob asked: I just received my K2 today, serial# 4998. I was wondering if the Kester solder I have, 244-6337-8800 which is a 245 NO CLEAN FLUX CORE SOLDER, ALLOY-63/37, .031' can be used to build the k2?
______ The 245 is a good rosin core solder that a lot of builders have used just fine, Bob. The Kester 44 is listed in the manuals because it's the "traditional" activated rosin core solder. Its flux may produce slightly better cleaning action. About the size, 0.031 is the size I use most commonly. Some builders prefer an even smaller solder. The trick is to avoid over-filling the pads. Since the holes are plated through, there's no need for fillets and they can cause you grief. One common problem is over-filling the pads for crystals so a solder fillet occurs out of sight under the crystal, shorting the circuit to the grounded crystal case. When that happens in the I.F. filters the effect is a 'deaf' radio and it's really tough to figure out why! So whatever size solder you use, avoid pushing too much of it into a joint. For the record, here's what Kester has to say about their 245 and the 44 fluxes. "Kester 245 No-clean Cored Wire was developed to complement low residue liquid fluxes being used by the electronics industry. The chemistry is based on some of the same principles that have been safely used for years in mildly activated rosin fluxes. The use of 245 No-clean Cored Wire results in visually acceptable assemblies without cleaning, yet soldering quality and efficiency is comparable to that obtained with mildly activated rosin flux." (http://tinyurl.com/ach76) "Kester 44 Rosin Flux is an activated rosin formula for use in flux-cored solder wire. Kester 44 Rosin Flux has virtually dominated the field of activated rosin core solders for well over four decades. An outstanding performance feature of this flux is the "instant-action" wetting behavior. The high mobility and fast-spreading action of this flux results in more reliable production line soldering....When exposed to an elevated temperature and humidity environment (38°C, 94% RH) for 72 hours, there is no evidence of corrosion caused by the flux residue. Throughout its many years of wide usage, 44 Rosin Flux has produced many billions of soldered connections. In all these billions of solder joints, involving the most delicate and critical of electrical and electronic components, there has never been an authentic instance of corrosion by the flux residue under normal conditions of use." (http://tinyurl.com/8nqrx) Ron AC7AC _______________________________________________ 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
