# Thread: Weight per Foot for Alum Extrusion

1. ## Weight per Foot for Alum Extrusion

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I used to have a LISP that would calculate weight per foot of aluminum extrusions. Many of these extrusions were hollow shapes with complex surfaces. I lost track of this many years ago but so I was hoping someone here might know how I could get something like this working. The attached file shows one of the extrusions I'm working with. I can run MASSPROP on it and get some information but how would one determine how much weight for aluminum would be involved with this and how could I calculate it in a fairly accurate manner?

UPDATE:

OK I think I figured out this much. The MASSPROP command tells me this thing has an area of 2.0874 square inches. I found a website which lists the weights and specific gravities for materials and it shows aluminum weighs 165 lbs per cubic foot. Based on that information I calculate:

1 cubic foot = 1728 cubic inches

165 / 1728 = .095486 lbs per cubic inch

thus

2.0874 * 12 inches = 25.0488 cubic inches per foot for this shape

thus

25.0488 * .095486 = 2.39183 lbs per lineal foot for this shape

As extremely accurate measurements are needed for this exercise I used the above precisions for my calculations. I'm very rusty at this stuff so any comments or suggestions would be appreciated. I recall the LISP program I used for this years ago would actually draw a nice box around the text and it would make a informative print out next to the shape you ran this on in the model space. But that was way back in AutoCAD 10.

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