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I want to solder a ground wire to the d-sub connector's metal shield( the bright color metal part of the connector), using tin-lead solder 60-40. I just wonder what kind of metal it is. I searched the web and couldn't find the answer.

This kind of connectors enter image description here

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    \$\begingroup\$ It's whatever metal the manufacturer of that particular connector decided to use. There is no definitive generic answer other than "Read the datasheet". \$\endgroup\$ – brhans Jul 6 '17 at 17:50
  • \$\begingroup\$ use some sandpaper and the conductive glue sold at radio shack; works with all metals \$\endgroup\$ – dandavis Jul 6 '17 at 19:23
  • \$\begingroup\$ Just get a big solder gun or iron and try it! (near the edges, you don't want the plastic to melt.) \$\endgroup\$ – George Herold Jul 6 '17 at 19:28
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Finding the datasheet or mechanical drawing of your part would be the best way of getting the answer.

Taking one connector at random on digi-key, http://www.assmann-wsw.com/fileadmin/datasheets/ASS_4884_CO.pdf you can find that the shell is SPCC. So soft steel. Not so fun to solder on.

Some (most?) shells are plated though, with copper, tin and/or nickel, which are much nicer to solder on.

The other factor is that the shell is basically a HUGE heat sink (in terms of soldering electronic components) so you might have a hard time getting it hot enough to have a good solder join.

Good luck.

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It is commonly nickel-plated steel.

Soldering to this requires an immersion flash-gold plating process, which is probably beyond your means.

Otherwise, HCl acid with ZCl and NH4Cl and cleaners with toxic fumes when soldering is also not recommended.

The recommended solution is to use a thin ring-term. lug on outside screw connection to chassis ground and crimp wire connection to lug.

One example might be to terminate a shield at one source only to circuit 0V to prevent ground fault currents yet provide 0V coupling to reduce noise. The shield area has a 1/4 wavelength of several GHz so it practically won't see any egress in normal applications but ingress might only come from arc welders nearby or more likely ESD discharge. In which case I would prefer 10kV insulation over a low impedance current path for ESD to go around a plastic shell screws with heat shrink. But you may have different requirements. Others might terminate to pin 7 ground, but then ESD tests to shell may induce a false start bit. This may be irrelevant to you but are real issues for commercial equipment.

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  • \$\begingroup\$ Huh, I've never had a problem soldering to DB9 connectors, nor to nickle plated brass stand-offs. I wouldn't think the steel underneath made much of a difference. Then again with the right flux I solder to stainless steel and Al. \$\endgroup\$ – George Herold Jul 6 '17 at 19:26
  • \$\begingroup\$ Even with standard rosin flux, nickel solders fine. The trick is to get it hot enough, which can be a problem with a fine-tip soldering iron, given the large size of the body. \$\endgroup\$ – WhatRoughBeast Jul 6 '17 at 19:54
  • \$\begingroup\$ Does it pass the 5lb pull test? or is it just tacked on, solderability is defined by this adhesion test. \$\endgroup\$ – Sunnyskyguy EE75 Jul 6 '17 at 20:14
  • \$\begingroup\$ @TonyStewart.EEsince'75 - Oh, tacked on for sure. But keep in mind the difference between military and hobbyist solder philosopy: hobbyist assumes solder has infinite strength, military assumes zero strength. I go with military, so any joint made by laying a wire on a surface and soldering should be assumed to fail under mechanical load. It's still useful, sometimes. \$\endgroup\$ – WhatRoughBeast Jul 6 '17 at 21:28
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They tend to be steel, sometimes plated with nickel. I have also seen some that are die cast zinc or nickel, too. The actual manufacturer will generally give you this information in their datasheets.

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In general, the d-sub connector housing material is SPCC, but there are also some SUS301 and SUS304 stainless steel.

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