Measure Surface Area of 3D parts?

A. I think you are on the best and simplest track if the article is of constant thickness.

A. You could determine surface area by plating your sample together with a flat sheet with a known surface in an electroless nickel bath. You should weigh sample and sheet before and after plating and calculate the unknown surface by the simple relations.

! Thank you for this idea, Mr. Livshitz, it's a great one!

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2003

A. Certainly, Tom. Just divide the weight of the article by the density of the metal in question, and you have its volume. Divide the volume by the thickness and you have the area.

A. Three pretty good ways were proposed, KT -- I especially liked the one about plating the part with electroless nickel. A better way would be a camera and software that could inspect the part and calculate its surface area. It doesn't sound hopelessly difficult but I haven't seen such a thing marketed yet. Good luck.

A. Measure the surface of a given length of wire and then weigh that piece of wire to get surface area per gram.

A. The surface area of a steel stamping can be determined fairly readily mathematically. The surface area of the faces (in square feet per pound) is given by 0.04903 divided by the thickness in inches. To this can be added the edge area, determined by estimating (or calculating) the edge area as a percent of the face area. I won't go through the arithmetic, but it is quite straightforward. It is important to recognize that the stamping can be bent, shaped, twisted, or deformed in many ways without changing the surface area. So all you need to do is weigh the part and apply the formula. For other metals, you can adjust this formula by comparing the density of steel with the density of the metal from which the article was fabricated. For example, an article fabricated from 12 gage steel (thickness of 0.1046 inches) will have 0.4687 square feet per pound on the faces of the article. This is the easiest way to determine the surface area of the part, and this approach has many other derivative benefits, including the gravimetric determination of coating weight.

A. Silvio, I do not think your approach is viable. For example, consider two pieces of wire of the same weight. One has half the diameter of the other. Therefore it will have twice the surface area. Yet they will displace the same amount of water. The only thing your test will tell you is the density of the material tested, and, unless your technique is exceptionally good, it is unlikely that it will be as accurate as the densities you can look up in the Handbook of Chemistry and Physics or Machinery's Handbook or the like.

You might remember the story of Archimedes of Syracuse shouting 'Eureka!' when he discovered this approach while immersing himself in a bathtub. (This is a little different from Archimedes Principle.)

In my humble opinion, the best way to determine the surface area of an article fabricated from wire is to use this formula (which applies to steel): the surface area in square feet is given by 0.09805 divided by the diameter in inches. This assumes that the article is long enough to ignore the ends of the wire. I won't go through the arithmetic, but is is quite straightforward. So all you need to do is weigh the article and apply the formula. For example, an article fabricated from 24 gage steel (U.S. Steel Wire Gage; there are other gaging systems; check Machinery's Handbook for details) which has a diameter of 0.0230 inches, will have 4.263 square feet per pound. If the article were fabricated from copper (density 8.92 g/cc) instead of steel (approximately 7.75 g/cc) it would have 13.12% less surface area or 3.704 square feet per pound. You can make other adjustments for other metals or alloys. I believe that this approach is a lot easier and more accurate than plate-weigh-strip-weigh measurements.

This approach and formula has many other derivative benefits, including the gravimetric determination of coating weight.

A. Draw it, if possible, on Rhino and then calculate area.