Tim NZ8J, Your roll of Kester solder would appear to be "44" Rosin Core Solder. I have a roll in front of me which contains the following codes, Sn63Pb37, 66, .75 mm (.030") and is identified definetly as "44" Rosin Core Solder made by Litton/Kester Solder, Brantford, Ontario, Canada I have used it to assemble two K2's, a KPA100, etc. Go for it! 73, Bob VE3XM