Has anybody had any success soldering nipples onto stainless steel control cables? I've tried using phosphoric acid from a tatooist as flux but the solder just doesn't want to flow into the cable.
Does the solder need to flow into the cable? I mean, if the end of the cable is splayed to prevent it pulling back through and the brass nipple is filled with solder, the cable can't go anywhere?
David, I would recommend talking to the guys at Warton Metals about suitable solders and fluxes for this job. I found them very helpful. For my cables(zinc plated steel) they suggested their 96S solder (96% tin, 4% silver) with acid core flux. I believe this will work on stainless as well. Warton can be contacted on 01706 218888. Unless the solder "wets" the wire you won't get the capillary attraction that draws the solder into the nipple.
I've had no problems with galvanised cables and I would expect the solder to flow into the cable to effect a proper job. The various threads on other websites seem to fight shy of the stainless steel issue though some do talk about a solder pot and dipping the cable into a small pot of molten solder. I haven't tried that yet There is a fine line between heating the wire to get solder to melt (and run off) and getting the wire red hot. I have tried phosphoric acid used by tatoo artists for piercings and Bakers fluid seems to fail as well. Some in the cycling fraternity swear by superglueing their nipples on (cable nipples that is) which sounds a bit iffy to me.
Stainless gets brittle with work-hardening from flexing so galvanised is probably preferable, but if you are keen to use it, silver solder works with S/S.
I should think it's the flux that needs to be identified as usable rather than the type of solder Tom. Just dip the ends in a lead/acid battery eh?
The neatest soldering I have seen was in a back street bike shop in Dundee. Bar solder was melted in an old ladle over a small gas stove and the cable end and nipple dipped in. Worked beautifully. If you are soldering a nipple onto an old cable, I can recommend cleaning the cable with electrical switch aerosol cleaner, then coating in flux. Works a treat. As for stainless control cables, I have used stainless cable inners on my mountain bike for years with no breakages.