Does anyone know if the weight is the same as the ano’d versions, or is it heavier?

# Nickel Summit

**jupdyke**#3

The following is preformed by a trained professional. Don’t try this at home.

# First the short answer

The annodized yoyo will weight about a half of a gram more.

# The long answer

Constants:

6061 Aluminum has a density of 2.70 g/cm^3

Aluminum Oxide (Al2O3) has a density of 3.95 g/cm^3

Assumptions:

- The typical hard coat anodizing is approx 0.002" of an inch thick. This in split between half penetration and half build up. I actually just talked to an annodizing company about this for a work project and the 0.002" is straight from them.
- Typical volume of an aluminum yoyo is between 10-12 cm^3
- Typical surface area is approximately 150-200 cm^2
- Volume of the Al2O3 can be calculated as surface area x thickness (not 100% true, but close enough for our calculations)
- Weight of the dye is negligible.

Some math using values from one of the CAD models of a yoyo that I am working on machining:

Volume from CAD 22.06 cm^3

Surface area from CAD 162.92 cm^2

Weight if Solid Aluminum = Volume* Density = (22.06 cm^3) * (2.70 g/cm^3) = 59.562 g

Weight with Aluminum Oxide layer =

(Total Volume - Volume converted to Al2O3) * density of Al

- (Volume grown of Al2O3) * density of Al203 =

(22.06 cm^3 - 162.92cm^2 * 0.001in * [2.54cm/1in]) * 2.70 g/cm^3 +

(162.92 cm^2 *0.001in * [2.54cm/1in]) * 3.95 g/cm^3 =

(22.06 cm^3 - 162.92cm^2 * 0.00254cm) * 2.70 g/cm^3 +

(162.92 cm^2 * 0.00254cm) * 3.95 g/cm^3 =

(22.06 cm^3 - 0.4138168 cm^3) * 2.70 g/cm^3 +

(162.92 cm^2 * 0.4138168 cm^3) * 3.95 g/cm^3 =

21.6461832 cm^3 * 2.70 g/cm^3 + 0.4138168 cm^3 * 3.95 g/cm^3 =

58.44469464 g +1.63457636 g = 60.079271g

That is a difference of 0.517271 grams.

Keep in mind that aluminum oxidizes naturally and creates a Al2O3 layer if exposed to air, specifically oxygen. That is why if you cut piece of aluminum in half it will be a very shiny silver, but after some time turns a matte gray color. The shiny surface is aluminum, the dull gray is aluminum oxide. My calculations ignore this layer because it is very thin. The natural aluminum oxide layer is about 4 nanometers or 4.0 × 10-7 centimeters thick.

Annodizing it first strips this layer off and then grows a thicker layer of Al2O3 with acid and electricity. The Annodized layer is about 12700 times thicker than a naturally formed Al203 layer.

Josh

P.S. my trained professional comment was a joke. I fully encourage you to do math at home. Don’t forget to show your work.

**jupdyke**#4

Just for fun I decided to prove that calculating the volume of the shell by multiplying the surface area by the thickness was close. I used my cad software to shell the hubs. This is what I got:

Volume = 0.4129175 cm^3.

The value I calculated was 0.4138168 cm^3.

Good enough for the girls I date.

Josh

**SloppyBinds**#5

I have had both nickel and anodized versions of the Y-Factor and Code 2. In both cases, the nickel version was heaver by at least half a gram.

**dirty_birdy**#6

Nickel plated versions are always a tad heavier than the regular ano’d versions…(and yes, this answer does take into effect the incredibly small yoyo to yoyo variations that exist in any precision machining operation). I do have “a couple” of nickel One Drops, and the difference is as stated.

db

**jupdyke**#7

Crap, I thought you were asking if an anodized yoyo would weigh more than one that is not annodized.

Density of nickel is 8.908 g·cm^3 and assuming the thickness of the nickel plating is the same as annodized then it would weigh about 2.05 grams more.

Josh