0
\$\begingroup\$

Is it possible to solder Nichrome wire (30AWG) to stainless steel and then the steel to a PCB?

\$\endgroup\$
  • \$\begingroup\$ If you solder nichrome, won't it melt when it heats up? \$\endgroup\$ – pjc50 Jul 21 '16 at 13:04
  • 1
    \$\begingroup\$ Such connections are usually crimped or welded, not soldered. \$\endgroup\$ – Dave Tweed Jul 21 '16 at 15:35
  • \$\begingroup\$ What Dave said. Spotwelding (many sorts to investigate, some can be done DIY) is reliable but ultrasonic welding may be used on certain cases, crimping probably most common. While I have not tried it I have considered a convenient termination method for such cases, take the wire, fold double, slip into thin (perhaps tinned) copper or brass tube and crush under a screw terminal. \$\endgroup\$ – KalleMP Jul 31 '16 at 6:40
1
\$\begingroup\$

Nichrome is very refractory- it melts at around 1400°C- so that's not a problem.

Both stainless steel and Nichrome have oxide layers that render them impossible to soft solder. It's possible to silver solder (braze) them with high temperatures (eg. a propane torch), silver solder and brazing flux but that's not a lot of use if you want to connect to a PCB since the stainless steel is not soft solderable (the silver solder itself is soft solderable, if I recall correctly).

Pressure contact is one possibility (a terminal strip or a threaded stud) or you could spot weld or silver solder the Nichrome wire to a copper wire that could then be soft soldered.

\$\endgroup\$
  • \$\begingroup\$ Spehro...I've had very good results soldering stainless steel. As I remember, I used a little dilute hydrochloric acid for flux, but "acid" flux solder might work as well. Clean the joint well. Never tried Nichrome \$\endgroup\$ – Robert Endl Jul 21 '16 at 14:29
  • \$\begingroup\$ Also, I don't think the solder alloy has any affect, only the flux. \$\endgroup\$ – Robert Endl Jul 21 '16 at 16:10
  • \$\begingroup\$ @RobertEndl Sure. You also can get special solder/flux for stainless steel from (for example) McMaster. It works okay, not as nice as bright copper. I was just trying to simplify it for the OP- regular fluxed solder won't work at all. Of course if the OP tries HCl, it needs to be thoroughly cleaned afterward as it's corrosive and ionic (so it will conduct and can cause severe problems). \$\endgroup\$ – Spehro Pefhany Jul 21 '16 at 16:11
  • \$\begingroup\$ P.S. Acid core (plumbing solder) apparently uses analine hydrochloride, at least Kester's stuff does. It's reportedly also hygroscopic so it will absorb moisture from the air to cause electrical problems if traces remain. \$\endgroup\$ – Spehro Pefhany Jul 21 '16 at 16:19
  • \$\begingroup\$ HCl flux is not something you want to use everyday. But, it can't be much worse than water-soluable flux. \$\endgroup\$ – Robert Endl Jul 21 '16 at 20:00

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.