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

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  • Member since
    October 2020
How do common model-making materials compare in strength? (i.e. Their resistance to becoming permanently bent out of shape)
Posted by SHIP691 on Monday, October 12, 2020 5:39 PM

Hello

Where can I find out how the approximate comparative strength of various different model-making materials?

i.e. I need to know how much force I can apply to a material before it starts to be bending permanently.

e.g. Suppose I was trying to bend a 1mm square bar, how would the following materials compare?
- Titanium (Grade 5)
- Brass
- Aluminium (in whatever grades are commonly available =??)
- Mild steel
- Annealed high carbon spring steel
- Tempered high carbon spring steel

And what about some more obscure materials like:
- Carbon fibre?
- Beryllium copper??

Background

I am trying to find an extremely robust material that is not magnetic (i.e. not ferromagnetic). It doesn't matter if it flexes somewhat, but it must not become PERMANENTLY bent out of shape.  I am looking to buy a 1mm square bar (or 1mm diametre).  I am trying to avoid having to heat-treat/temper my material (but I could do so if I have to). 

e.g. I tried looking up MatWeb.com but it was too detailed, and I couldn't work out how to use it. 

J

  • Member since
    July 2004
  • From: Sonora Desert
Posted by stikpusher on Monday, October 12, 2020 8:47 PM

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.

 

F is for FIRE, That burns down the whole town!

U is for URANIUM... BOMBS!

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LSM

 

  • Member since
    March 2003
  • From: Towson MD
Posted by gregbale on Tuesday, October 13, 2020 6:04 AM

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. Whistling

Greg

 George Lewis:

"Every time you correct me on my grammar I love you a little fewer."
  • Member since
    October 2020
Posted by SHIP691 on Tuesday, October 13, 2020 8:51 AM

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 am trying to design a slim (1mm) magnet that is sandwiched between 2 steel plates (that are also 1mm thick), that is attached to some carboard by a non-magnetic pin, that is attached to the bottom steel. The whole thing needs to be 3mm thick. 

The top and bottom surfaces of the steels must be flush with the top and bottom surfaces of the cardboard.

Here is a simplified diagram.

magnetic paddle

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

  • Member since
    September 2012
Posted by GMorrison on Tuesday, October 13, 2020 10:04 AM

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

 

Modeling is an excuse to buy books

 

  • Member since
    March 2003
  • From: Towson MD
Posted by gregbale on Tuesday, October 13, 2020 10:33 AM

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?

Greg

 George Lewis:

"Every time you correct me on my grammar I love you a little fewer."
  • Member since
    May 2013
  • From: Indiana, USA
Posted by Greg on Tuesday, October 13, 2020 11:06 AM

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.

-Greg

  • Member since
    May 2020
  • From: North East of England
Posted by Hutch6390 on Tuesday, October 13, 2020 11:11 AM

SHIP691
some of the forces will be sustained, but the strongest forces will be short in duration

I'm intrigued - what are you making?

Vell, Zaphod's just zis guy, you know?

  • Member since
    November 2009
  • From: Twin Cities of Minnesota
Posted by Don Stauffer on Tuesday, October 13, 2020 12:38 PM

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.

 

Don Stauffer in Minnesota

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