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I have an application where a small daughter board is elevated and needs very minimal support. The supports for the board need to be very thin, as stiff as possible, electrically conductive and solderable. The current is very minimal - say 50 mA tops, so thin wire could be a possibility.

Some different things come to mind.

Beryllium copper comes to mind but I'm that anxious to be manufacturing with toxic materials, plus probably expensive.

Piano wire might be a possibility but would probably require an acid flux. It's a possibility but would require careful cleaning after solder.

Stainless wire - which might be the leading candidate before doing any research. I was wondering about maybe getting steel or stainless wire plated for solderability.

Anyone done anything similar or got any starting points on the problem?

Editing this question to answer some questions. Sorry if there's a better protocol here. Please clue me in if there's a better way.

Thank you so much for all the answers! Really good suggestions!

Why do the supports "need to be very thin"? – Spehro Pefhany

Airflow is an issue. I want minimum turbulence / interference.

How long will each wire be, and how much resistance is acceptable? > What is the maximum acceptable thickness? "...as stiff as possible" > Bruce Abbott

It's part of an assembly / sandwich so mechanical issues come into play.

My "very thin" might be a foot across, or 1𝜇m, depending on my > background. What's "very thin" to you? Are you looking for existing > wires, or could you make something up? I'm thinking pre-tinned or > > copper-plated music wire should work nicely. – TimWescott

Sorry you're entirely correct. I'm guessing in the .015" to .022" range. .35mm - .55mm thickness. 45-75 mm long

Wire wrap pins. – user_1818839

Might work - not sure they're long enough. Sharp edges not a plus.

I think I'm looking for something that is "spring hard". Tin plating might be an option - thanks to whomever suggested that. Tin plus gold would be fabulous. Just a small project now. It's possible I'd get something plated down the line if the product is successful.

Pure and/or plated nickel electric guitar strings are readily available in gauges down to 0.008". Stop by any music shop. Usually you can buy individual strings, but you may need to lay down for a whole pack. Less than $10. I believe nickel is generally not as solderable as copper or gold, but way more so than stainless. If you can handle slightly thicker wire you can use bronze acoustic guitar strings (maybe around 0.020" because it's bronze wire wrapped on a steel core.) Not as thin or stiff as nickel, but for sure very solderable. (Bronze = copper and tin, basically.) Kyle B

Resistance might be an issue. Also not stiff enough I think.

Steel sewing pins - much stiffer than copper wires. – brhans

It's a thought - worth a quick google. I've seen needles, but not pins, gold plated.

Piano wire is a common name for a hardened steel wire. – Kartman

I'm aware. It also comes hardened. Plated would be ideal. Anyone have a source?

What's wrong with just really longer square header pins? – DKNguyen

I might end up there. Square edges not ideal. They are .025" in my memory.

Dress-making pins are about 30 mm long, thinner than header pins, stiff as they're steel, and most types I've met are easily solderable. Don't cut them with nice new cutters though as they will damage the blades, use the cutters you damaged last year. – Neil_UK

Worth an investigation Neil. Resistance might be an issue. Gold plated?

These pins are looking good. Thicker than I wanted but ticks a lot of the boxes.

Do the wires all have to be parallel to each other? Hopefully not, because if you can have them at angles to each other, you can probably come up with a design where each wire only has to resist tension and compression. If they all have to be parallel, then they'll have to resist shear, too. Is there enough airflow to produce significant forces? – Tanner Swett

Fastened to architecture - not such high wind speeds. I did think about not making them parallel so the module does not slew or vibrate. Lots of stuff to think about in this engineering business.

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    \$\begingroup\$ Why do the supports "need to be very thin"? \$\endgroup\$ Commented Jan 7, 2022 at 22:43
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    \$\begingroup\$ How long will each wire be, and how much resistance is acceptable? What is the maximum acceptable thickness? "...as stiff as possible" - Why? \$\endgroup\$ Commented Jan 7, 2022 at 22:46
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    \$\begingroup\$ My "very thin" might be a foot across, or 1\$\mu\$m, depending on my background. What's "very thin" to you? Are you looking for existing wires, or could you make something up? I'm thinking pre-tinned or copper-plated music wire should work nicely. \$\endgroup\$
    – TimWescott
    Commented Jan 7, 2022 at 23:02
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    \$\begingroup\$ In general, where you're using superlatives or other descriptive words, please edit your question with engineering units. At least give us starter values. \$\endgroup\$
    – TimWescott
    Commented Jan 7, 2022 at 23:04
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    \$\begingroup\$ Wire wrap pins. \$\endgroup\$
    – user16324
    Commented Jan 7, 2022 at 23:08

3 Answers 3

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Long pin-headers are solderable, conductive, thin and stiff. How high does it have to be? We use 1" / 25mm pins.

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papreclip wire, that is, wire from paperclips.

it's some sort of medium carbon steel with a solderable plating. (possibly zinc)

If you want industrial quantities try tin plated spring steel wire.

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  • \$\begingroup\$ The very first thing that crossed my mind was spring steel. Since we are in congruence, +1! \$\endgroup\$
    – jonk
    Commented Jan 8, 2022 at 6:05
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Tinned steel wire from 1/4 W resistors , doubled up at each location, ought to do the job for a penny and allow for 0.4" spacing or less if microwashers or high-temp plastic are used just soldering the wire endpoints.

Although not very serviceable, that could be done micro-threaded spacers and screwed at one end, using the wires as hinges for service.

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