How much resin do I need?

How much resin do I need

How much resin should I mix for a project?

Originally published October 2014.  Updated February 2019.

When it comes to making things with resin, one of the tricky parts is knowing how much mixed resin you’re going to need. It’s important to make sure you have enough, but of course, you don’t want to waste any when making your resin jewelry, crafts and paintings. If you find yourself asking ‘How much resin do I need?’, here are a few tips and formulas to help you figure out how much resin you’re going to need to mix for a project.

Option 1:

If you are working with something with ‘sides’, like a mold or bezel, the most straightforward way to figure out the amount of resin you’re going to need is to pour water into the item, then measure that volume of water. A few key measurements are:

*1 milliliter (mL) equals 1 cc (cubic centimeter)
*1 teaspoon equals 5 mL
*1 ounce equals 30 mL
*1 cubic inch equals 16.3871 milliliters

Know that you are not going to catch every drop of water as it comes out of your mold or bezel, so you may want to mix a little more resin to account for this.

Make sure your item are dry first before pouring in the resin.

Option 2:

For the times when you want to be more exact, or if you are trying to calculate the amount of resin to go on a flat surface like a painting, you can take measurements of the area and figure out the volume of resin needed by multiplying the length times width times height.

Here’s an example: 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 (from option 1), this mold cavity will hold approximately 8.189355 mL (the math is 16.3871 x .5). I would just round up to 9 mL from here.

This article explains more for calculating the amount of resin to cover a painting.

Option 3:

What do you do if you are casting resin into a cylinder or sphere?

We’re are getting deep into the math now.  🙂  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 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 casting a half sphere (like mold 429) or half cylinder (like mold 443), divide your volume by two.

resin bangle mold 414

Here’s an example I use quite frequently. I’m going to make a casting with with this chunky bangle bracelet mold. Here are the dimensions: 2 5/8 inches inner diameter, 5/8 inches wide, 3/4 inches tall.

Let’s get the volume of the ‘outer’ circle: 2 5/8 inches plus 5/8 inches times two (two because of each side) 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.

Like this post? You may be interested in  How to make resin jewelry

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 of resin needed for your project.

Other things you need to know if you are asking how much resin do I need:

1.  Resin needs a minimum amount of resin and hardener mixed together to generate enough heat to start the curing process.  Make sure after you have made your calculations that you are mixing the manufacturer’s recommended minimum mixing amount.  The flip side of that is true as well.  Make sure the amount you need doesn’t go over the manufacturer’s maximum recommended mixing amount.  If it does, you will need to divide that amount up into the appropriate number of castings so you don’t generate too much heat at once.

2.  Always err on the side of mixing a little more rather than a little less.  If you have some leftover resin, have some backup projects ready to go.  One of my favorites is turning your favorite scrapbooking papers into wearable jewelry using resin.

3.  To make sure you get accurate measurements, I always recommend using graduated cups.  We have them in the 1 ounce and 10 ounce size.  The 1 ounce cups have milliliter marks on them as well as ounce marks.

Phew! Now that I’ve made your head spin, go cast some resin!

 

Unpublished Blog Posts of Resin Obsession, LLC © 2019 Resin Obsession, LLC

 

13 Comments

Morgan

I was pouring a layer of clear cast 7050 over painted woof frames. I did give the hsrdener and resin a warm bath for about 5 minutes after coating the third one, it got like hard taffy and smoke actually stsrted to come from it. Did I give it too long of a bsth? Any help is much appreciated.

Reply
Katherine Swift

Yes, it sounds like it heated up quickly, which caused it to cure quicker than expected.

Reply
Carla

When measuring out resin and hardener I read that the cough syrup measuring cups are the best to use. Can they be reused? I literally threw away a stack of them several months ago… until I caught the “Resin jewelry bug”! I’m sure the answer is somewhere, but I have read and watched so many tutorials lately I’ve probably missed it! Thanks

Reply
Lili

Hi how much resin should I mix i f I need to create a big canvas (like your videos) , the measure is 1 milliliter of resin vs 1cc of area?. thanks a lot.

Reply
Katherine Swift

I would start with using the formula I show in the article.

Reply
Laurelgreenart

I want to buy a larger volume of Eli Chem’s resin. Will you be offering their Ultra Cast extended use resin in 7 liter volume?
I live in Texas.

Reply
tamara

all i need to know is how many ounces of resin / hardener do i use to do 2by2 sqare feet canvas? simple lamen terms please not math mumbo jumbo i just do not get it…

Reply
David Hands

I’m looking to make a diorama using a 36″ model submarine. I will be cutting the hull off below the water line so I’ll be needing approximately 42″ length by 7″ width and a depth of around 1-1.5″. I don’t want to buy way more than I need (and don’t want to run out part way through). What sort of weight would I need for this? (I’ve never used resin before). Thanks.

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