pot melt into a square or retangle

Home Forums Glass Fusing General Fusing Discussion pot melt into a square or retangle

Viewing 6 posts - 1 through 6 (of 6 total)
  • Author
  • #10083

    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.


    I 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.



    Length 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.


    Circles 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

    Stephen Richard

    Look 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/


    Thanks to everyone- I will try another potmelt.

Viewing 6 posts - 1 through 6 (of 6 total)
  • You must be logged in to reply to this topic.

People Who Like Thisx