Re: Fine wire tensile strengths?

Jul 31, 2010 2 Replies


I've been asked to 'light-up' aircraft models, such as,


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> It is suspended from a rope.
> I need to use very fine 120V wire (like magnetic wire), the model uses
> 8# test monofilament right now and weighs 1/2 # , but a strong wind
> requires that 8# test. Is there a table that gives wire gauge & tensile
> strength? The current will likely be a max of 1/2 amp. Ken

Resistance and stretch calculators for lots of materials can be found at . Eg, click the Steel button, submit, choose resistance calculator, put in wire area and length, etc. Or click the Young's Modulus button, put in area, length, and load, then observe Change in Length result.


Numbers in the ARRL handbook chart of breaking load for copper antenna wire work out to about 39000 psi for soft drawn copper wire and 65000 psi for hard drawn so perhaps use 2 strands of varnished #24 or #26 copper magnet wire. Those strength numbers are higher than Tim mentioned so run deadweight tests before testing with model. #26 is ok on ampacity. Copperclad steel antenna wire is two or three times as strong but only 40% as conductive.


Offhand, 60W of lighting within a model sounds like a lot. Have you considered low-voltage wiring with high-brightness LED's?

65 KSI is close to the ultimate tensile strength I saw; I specified = yield strength, which is a little lower of course.

The yield of dead soft copper is astonishingly low, it's like shiny pink = clay. Only that, after you push it around a bit, it hardens up, and = pretty soon it's so damn strong you can't bend it by hand anymore! = Copper provides a particularly dramatic illustration of work hardening.

Tim

--=20 Deep Friar: a very philosophical monk. Website:

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strength, which is a little lower of course.

clay. Only that, after you push it around a bit, it hardens up, and pretty soon it's so damn strong you can't bend it by hand anymore! Copper provides a particularly dramatic illustration of work hardening.

I got to much finer wire #39. But have a current limit (~18 mA) that nearly forces an all LED solution.

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