Sapphire 145 (Detail Solder) Sapphire 145 is 0.8mm diameter solder with no peaking and which flows absolutely brilliantly. It has a very narrow melt range which makes quick joints on detail parts a pleasure yet it flows exceptionally well for long seams on brass kits. Whilst we recommend that it is used with our Sapphire flux and no-clean flux it also has a multiple flux core to assist wetting and flow. This specially formulated solder for brass or nickel silver kit assembly is simply the very best available anywhere! Sapphire 145 used by some of the best professional loco builders in the world simply because it works better!