# pot melt into a square or retangle

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- This topic has 5 replies, 4 voices, and was last updated 7 years, 8 months ago by betnca.

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- January 27, 2014 at 10:22 pm #10083betncaParticipant
I need the formula for determining how much glass would go into a square or rectangular pot melt. know I saw a formula somewhere but can’t find it. For instance, if I wanted to make the slab 1/4 in thick and 6 x 4 inches. The formula involved determining how many grams of glass I would need. Thanks for anyone’s help.

January 28, 2014 at 7:38 pm #13219TheMacdonaldParticipantI am certain there is a simpler way to calculate, but here’s what I did:

6×4= 24 square inches

http://www.onlineconversion.com/ to calculate the diameter of a circle with an area of 24 square inches. 5.54 inch diameter

Then used Paul’s calculator above to estimate 9 ounces of glass.

SOMEBODY else might check the math and theory.

TAM

February 1, 2014 at 5:41 pm #13220JeaniceParticipantLength x Width x Height = Volume

6.00 x 4.00 x 0.25 = 6.00 cubic inches

Convert cubic inches to cubic centimeters. You MUST convert your volume to cubic centimeters or the calculation won’t work. It may be easier to just measure in centimeters.

6.00 cubic inches = 98.32 cubic centimeters (cc)

Now, mulitply that by 2.5, which is the specific gravity of glass.

98.32 x 2.5 = 245.8 grams. So you will need 245.8 grams of glass. (Might want to add extra to account for the glass that will stick to the pot.)

If you

**measure in centimeters**in the beginning the calculation is**VERY easy**.**Length x Width x Height x 2.5 = grams of glass needed**Now you can convert grams to ounces if you want or need to.

February 1, 2014 at 5:54 pm #13221JeaniceParticipantCircles have a different equation. Remember that a radius is half the diameter of the circle. An 8 inch circle has a 4 inch radius. A 10 inch circle has a 5 inch radius.

Volume of a circle = 3.14 x radius x radius x height

So if we want an 8 inch circle that is 1/4 inch thick…

3.14 x 4.00 x 4.00 x 0.25 = 12.56 cubic inches

Again we have to convert those pesky inches to centimeters

12.56 cubic inches = 205.82 cubic centimeters

Now mulitpy by 2.5 just like with rectangles

205.82 x 2.5 = 514.55 grams Tada!

Again, if you

**start with centimeters it is MUCH easier****3.14 x radius x radius x height x 2.5****= grams of glass needed**February 2, 2014 at 8:04 am #13222Stephen RichardParticipantLook at “tools” I. The menu bar at the top of the page. There is a calculator there.

Stephen Richard

blogs at: http://www.verrier-glass.blogspot.com/ and http://www.glasstips.blogspot.com/

February 7, 2014 at 5:27 pm #13223betncaParticipantThanks to everyone- I will try another potmelt.

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