## Thursday, July 12, 2012

### How many rhinestones will I need? Method#2: Calculating the surface area of each rhinestones

In the previous post, I've talked about how to determine the number of rhinestones needed by knowing the number of rhinestones to cover one square inch. Today, I'll show another method to estimate the number of rhinestones needed for a project.

Last passage, I've talked about the Stone Size, let's recap as follows:
ss5 (1.70-1.90mm)
ss6 (1.90-2.10mm)
ss8 (2.30-2.50mm)
ss10 (2.70-2.90mm)
ss12 (3.00-3.20mm)
ss16 (3.80-4.00mm)
ss20 (4.60-4.80mm)
ss30 (6.32-6.50mm)
ss34 (7.07-7.27mm)

EXAMPLE:

To estimate the number of crystals needed, we will need to know the Surface Area of the stones, I'll take SS12 rhinestones as an example:

Formula to calculate a surface area of a circle: 3.14 X (Diameter/2) Square
Surface Area of ss12:  3.14 X 1.5 X 1.5 = 7.07 mm sq.

For example, if we are going to cover a iphone case by rhinestones ss12,
the iPhone surface area will be: 58.6 mm X 118.2 mm = 6750 mm sq.

Then, number of stones needed = 6750 / 7.07 = 954 rhinestones.

This method can be useful if you want to know a very accurate number of rhinestones needed for your project. By using this formula, you're assuming your item are 100% covered by the rhinestones, not like the #1 method we talked yesterday.

However, it's unlikely to the item 100% covered without any spaces in between the stones, So, the actual number of rhinestones needed maybe slighlty less than the number you got from the calculation.