How do common model-making materials compare in strength? (i.e. Their resistance to becoming permanently bent out of shape)

Common model making materials? Well most kits are styrene plastic, which has varying levels of flexibility depending upon the company. Resin, has minimal flexibility. And the main metals: brass, white metal (a lead/tin alloy?), and aluminum, are all fairly malleable, with brass being the strongest.

From a mechanical /physics standpoint, your question is missing a few critical elements...such as whether you're talking about a momentary, sustained or repetitive force, and the length of the theoretical 1mm bar section involved.

It might save effort if you simply describe what it is you're trying to do. 

gregbale

From a mechanical /physics standpoint, your question is missing a few critical elements...such as whether you're talking about a momentary, sustained or repetitive force, and the length of the theoretical 1mm bar section involved.

It might save effort if you simply describe what it is you're trying to do.

I have yet to decide how long the non-magnetic pin needs to be - probably about 20mm. But that's not really the point as I have no need to optimise the design. I just need to build something over-engineered that works.  Like-for-like I want to know roughly how different materials compare. Yes some of the forces will be sustained, but the strongest forces will be short in duration.

with thanks

J

Hello. Are you a Turkish speaker? Just curious seeing "delme".

Without a deep dive into Hookes Law, all of the materials noted have some elasticity of deflection before permanent deformation.

The amount of deflection is partially due to the length of the part, hence coil springs which are made of a hard material but have a long length in a relatively small space.

Three of the materials you list are ferrous.

So by observation most springs are steel and that won't work for you.

A quick search of non-ferrous spring material suggests beryllium copper as a favorite, followed with nickel and brass.

Bill

Three questions spring to mind:

What range of force are you anticipating, and directed where?

Will the pin be secured between the cardboard layers in some fashion, or essentialy 'free floating?'

May one presume your critical point-of-force or 'weak point' is between the steel/magnet 'sandwich' and the cardboard edge, or somewhere else?

GMorrison

A quick search of non-ferrous spring material suggests beryllium copper as a favorite,

Based on your criteria, that was my choice too.

Be forewarned, stuff is an absolute nightmare to work with.

SHIP691

some of the forces will be sustained, but the strongest forces will be short in duration

I'm intrigued - what are you making?

Mild steel is very ferromagnetic.  Most stainless alloys are non-magnetic, a few aren't.  .  There are many alloys of aluminum, some are quite strong.  Carbon fiber is strong but brittle- does not bend well.

Many brass alloys can be hardened and made strong.  Also some bronze alloys are strong.  However, these alloys may not be readily available, and are hard to work with.  K&S brass is moderately strong.  They make a 1/8 inch tubing that is hardened and very stiff, but most is soft, not very ridged.

These two posts and then nothing...

Very mysterious - does anyone have any ideas about what the project might be?  A thin magnet sandwiched between two thin steel plates, attached by a hard, thin, bend-resistant rod to a piece of cardboard?  What would be the point of this (deliberately researched) very hard rod being fixed to a material that has very little strength itself and even disintegrates if it gets wet?

Well I did learn a few things doing a little research.

Deflection, deformation, harmonic vibration frequency, Hooke's Law. Takes me back to College Physics, earthquake design in architecture school.

The poster sparked my interest because he used the Turkish word for paddle; delme; in his sketch.

Oh well,

Bill

He posted the same question at Britmodeller...got the same range of replies...and remained just as cagey about what he had in mind:

"PS Background:
The design if part of a mad contraption that I am building (don't ask!)"

It's all Greek to me.