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Subject: 
Melting Point of ABS (Re: Strengthening Gears)
Newsgroups: 
lugnet.technic
Date: 
Tue, 5 Mar 2002 14:06:31 GMT
Viewed: 
6231 times
  
In lugnet.technic, David Schilling writes:
A quick search on Google shows that ABS (Acrylonitrile-butadiene-styrene)
has a melting point of 103-128°C.  Since water boils at 100°C, I don't have
any doubt that you would see some deformation by that point.

There are different grades of ABS, each having different mechanical
properties. I found an extensive resource on materials at: http://www.matweb.com

The ABS property data can be found here:
http://www.matweb.com/abspolymer.htm

I picked 3 grades of ABS that seemed likely to be the type(s) that Lego
uses, but I'm not sure:

ABS, Molded
http://www.matweb.com/SpecificMaterial.asp?bassnum=O1100
max service temp in air: 140 - 223 F
mold temperature: 109 - 149 F
processing temperature: 399 - 500 F

ABS, Impact Grade, Molded
http://www.matweb.com/SpecificMaterial.asp?bassnum=O1103
max service temp in air: 167 - 365 F
mold temperature: 111 - 149 F
processing temperature: 410 - 487 F

ABS, Extruded
http://www.matweb.com/SpecificMaterial.asp?bassnum=O1106
max service temp in air: 140 - 212 F
mold temperature: 136 F
processing temperature: 392 - 486 F

I'm not sure what the different terms mean, exactly. I can tell you all
about steel, but nothing about plastic :-)

What I think they indicate (please, someone correct me if I'm wrong) is that
the actual melting point is difficult to pick because of the gradual
softening of the material. I think the actual melting point, or rather the
point at which the material experiences permanent deformation, is dependant
on the applied stresses.

Obviously, there will be a point at which the material deforms under its own
weight, and that is perhaps the classic definition of melting. There will
also be a point at which the material can be safely molded by applied forces
without fracturing the material. This point is perhaps the "mold
temperature". The mold temperature will be much less than the "classic
melting point".

So, what use is this information? Will Lego pieces melt or not in boiling water?

The answer is: NO, they will not melt. However, they WILL permanently deform!

Boiling water (212 F) is much higher than the mold temperatures given above.
Therefore it is possible that the self weight of the material, and also
handling the material in and out of the water, will apply enough stress to
permanently deform (or "remold" if you like) the bricks.

The experiences that others have stated in the thread reinforces this.

TJ



Message has 3 Replies:
  Re: Melting Point of ABS (Re: Strengthening Gears)
 
The first one you cite is probably the right one for LEGO(R) Bricks. They're molded, not extruded and I don't believe they are impact grade. Thomas Avery <thomas.avery@intec-hou.com> wrote in message news:GsI76v.GED@lugnet.com... (...) have (...) (...) (22 years ago, 5-Mar-02, to lugnet.technic)
  Re: Melting Point of ABS (Re: Strengthening Gears)
 
The "service" temperature is the limit at what you should operate it at. The "mold" temperature is how LOW the mold has to be cooled to get a good shot. The "processing" temperature is the temperature the plastic has to be when it enters the mold. (...) (22 years ago, 5-Mar-02, to lugnet.technic)  
  Re: Melting Point of ABS (Re: Strengthening Gears)
 
Thomas: Lego uses primarily Bayer Novodur (and apparently to some extent Bayer Lustran) for its bricks. The exact composition of the Novodur is of course, like the recipie for Coke, is top secret, but it is probably closest to Bayer Novodur P2M-V A (...) (22 years ago, 6-Mar-02, to lugnet.technic)

Message is in Reply To:
  Re: Strengthening Gears
 
(...) A quick search on Google shows that ABS (Acrylonitrile-butad...e-styrene) has a melting point of 103-128°C. Since water boils at 100°C, I don't have any doubt that you would see some deformation by that point. -- David Schilling (22 years ago, 5-Mar-02, to lugnet.technic)

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