So I’m guessing you googled, ‘How much resin do I need?’ and ended up here. Kudos for thinking about that now instead of when you’re halfway through your project. Mixing way too much or not nearly enough epoxy resin is frustrating.
But so is math.
I’ve got three options for you from easiest to hardest to answer the question how much resin do I need.
Option 1: Use water
Difficulty level: Easy
If you’re working with something with ‘sides,’ (like a mold or bezel), fill it with water. Then, pour the water into a measuring spoon or cup.
*1 teaspoon equals 5 mL
*1 ounce equals 30 mL
Know that you won’t catch every drop of water. Mix a little more resin to account for this.
Option 2: Resin Calculator
Difficulty level: Easy to intermediate
Measure the length, width, and height of your item or flat surface.
Put them into this calculator. (Yes, it really is that easy to answer how much resin do I need)
If you’re coating resin on a surface, use 0.07 inches as the height. (That’s the level that resin for art settles to.)
⭐️ BONUS: Learn more about calculating the amount of resin to cover a painting.
Option 3: Do the math yourself
Difficulty level: Hard to Insane
For you crazy people that busted curves throughout high school and college, this is for you.
Although, you probably already knew this was your answer for how much resin do I need.
And for us mere mortals, you can skip this part.
Let’s say a mold cavity is 1 inch square by 1/2 inch deep.
1 inch x 1 inch x 1/2 inch equals 0.5 cubic inches. Since 1 cubic inch equals 16.3871 milliliters, this mold cavity holds 8.189355 ml (the math is 16.3871 x .5). I would just round up to 9 ml from here. Or round up to 10 ml to make it even easier.
What do you do if you are casting into a cylinder or sphere?
Cylinder volume equals Pi (3.14) x radius2 x height. Sphere volume equals 4/3 x Pi (3.14) x radius3
Note: Radius is the distance halfway across. Diameter is the distance all the way across. To get the radius, you will need to divide the diameter by 2. Don’t even ask me where that Pi number came from.
Don’t forget, if you’re only using half of a sphere mold, divide your volume by two.
What if your center is hollow?
Let’s do the math with this bangle bracelet mold.
The dimensions are 2 5/8 inches inner diameter, 5/8 inches wide, 3/4 inches tall.
The volume of the ‘outer’ circle: 2 5/8 inches plus 5/8 inches times two (two because of each side), which equals 3 7/8 inches total diameter. Using the formula above, the volume of a cylinder that size equals:
3.14 x (3.875/2)2x .75 which equals 8.84 cubic inches.
But hold on, we need to subtract the inner cylinder. Otherwise, it’s like we’re filling up the entire bracelet without a hole for your wrist.
Inner cylinder volume equals:
3.14 x (2.625/2)2x .75 which equals 4.057 cubic inches.
That means the volume of the bangle is 8.84 cubic inches minus 4.057 cubic inches, which equals 4.783 cubic inches. Since 4.783 cubic inches equals 78.38 milliliters (4.783 x 16.3871), divide that number by 30, and you get approximately 2.6 ounces.
There are a few other things you need to know if you are asking how much resin do I need:
1. After you’ve figured out how much resin do I need, make sure that you are mixing between the recommended minimum and maximum mixing amounts. If you don’t mix the minimum, your resin won’t cure. If you mix more than the maximum, it will overheat and smoke.
⭐️ BONUS: We’ve got those mixing amount numbers for you in our resin buying guide.
2. Always err on the side of mixing a little more rather than a little less. If you have some extra resin, have some leftover resin projects ready to go.
3. Now that you’ve done the math, measure your parts A and B accurately. Use mixing cups with graduated lines to make sure your amounts are correct.
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