I need to solder a very thin copper wire to a very thin stainless disk. Obviously regular rosin core electrical solder is not going to do it. Any suggestions without spending $25 for special flux just to apply .01 micrograms of solder?
An acid flux like Allstate Duzall 430 will work with the electrical solder.
Ned Simmons
HUH?
Any reasonable flux and good solder should have NO problems soldering to SS.
As a test I just took some SS I have (it's SS from hell, the old front of a dishwasher and harder than you'd believe) sanded it clean put a dab of Harris Stay-Clean flux on it and had no problems what so ever getitng a nice even flow of some Kester '44' (that's 63% SN Solder) with my good-ole Weller
260Watt The Harris Stay Clean (part number 40027) cost about 2 bucks for a 4 OZ plastic bottle is is just a super all around flux for soldering. It's intended for copper/brass but works wonders everywhere.--.- Dave
Try a tin-silver solder and ordinary soldering fluid for flux.
Email me your snailmail addy, and I'll send you a few inches of Harris Staybrite in an envelope. Staybrite melts at 430F, wets stainless (and copper) like tin-lead wets copper or brass, An ordinary soldering iron works fine.
I think Dan Caster once said that it doesn't work on some stainless alloys, but it's worked well on the alloys I've soldered with it.
Your solder should be fine, so long as you use the right flux. As a quick zero-cost hack, try using phosphoric acid as a flux. You probably have some around already for rust treatment. If it's clear or pink it's fine, but don't use it if it's opaque white - that's a better rust treatment (it has tannates in it too) but it's not a useful flux.
I've seen old "killed spirits" (Baker's Fluid / zinc in hydrochloric acid) flux used successfully as a flux for some grades of stainless, but neutralise it well afterwards (wash and rinse with bicarbonate of soda) as it's corrosive on thin copper wires.
If all else fails you might want to 'flash' copper over a stripe and then solder to it.
I have Kester 5% silver, tin-lead solder if needed.
Martin Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder
Glenn Ashmore wrote:
Abrading the stainless under an oxide cover of oil can get it clean enough to solder. You see, the problem with stainless is it contains chromium. And nickel, I think. The chromium oxides are really tough to dissolve, but if you remove them mechanically and don't allow air to contact the cleaned surface, the bare metal will take solder.
I haven't tried this on stainless or aluminum. It was recommeded here for aluminum, which is worse than stainless to solder.
Try an automotive AA cell powered paint chip grinder or a Dremel with a rubber abrasive (Cratex etc) tip.
Doug Goncz Replikon Research Falls Church, VA 22044-0394
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